Thermal paste is spread between two faces and pressed thin; a thermal pad is a pre-cut sheet. The sources say paste has better thermal performance and works as a thin layer, while a pad is easy to fit and can fill a larger gap. The difference is whether the material is spread on and pressed thin, or cut first and pressed in.
In this article, thermal paste means what the sources call thermal paste (also written thermal grease); thermal pad means thermal pad; phase-change sheets and liquid gap-filler compounds are outside its scope. It is divided into 4 points of comparison:
Point 1 | Gap and thickness: the sources say a pad fills a large gap and paste works as a thin layer, but one article says paste can also fill a larger gap.
Point 2 | Application and rework: a pad is easy to fit and paste is harder to apply; statements on reuse after taking apart disagree.
Point 3 | Insulation and mess: most pad types are insulating; paste depends on its composition, and spill-out may get onto the surroundings.
Point 4 | Thermal performance and long-term change: the sources say paste conducts heat better and a pad is more stable; some sources also remind readers not to look at thermal conductivity alone.
The sources and the basis for each are in the notes at the end; this article does not replace the material maker’s data sheet. This is the general case; individual cases still have to be judged on their own.
Figure 1: The four points of comparison between thermal paste and thermal pad: gap and thickness, application and rework, insulation and mess, thermal performance and long-term change (illustration, not to scale).
Point 1 | Gap and thickness: the sources say a pad fills a large gap and paste works as a thin layer, but one article says paste can also fill a larger gap
How to look at it:
Write down first: how large the gap between the two faces is, and how flat they are. The thickness figures differ by source: Source 4 writes paste at most 0.1 mm and pad 0.3 mm to 5 mm or more; Source 6 writes pad 0.2 to 20 mm; the figures are not converted into each other.
Whether paste can fill a larger gap: the statement of Source 2 and those of Sources 4, 5, and 6 disagree.
What the public sources say:
A blog article from a precision die-cut parts company (Source 1; October 8, 2014, personal byline, maker’s statement, with promotion, older) writes: both are used to fill the gap between a heat-generating component and a heat sink; a pad is a pre-formed rectangular or square solid material.
An article from a PCB design software company (Source 2; created March 31, 2017, updated July 27, 2021, personal byline, with promotion) writes: paste is liquid, and when the surface is uneven it can fill a larger gap more evenly than a pad; pads are almost all thicker than paste; the thinner the interface material layer, the better the heat conduction.
An article from a die-cut and component company (Source 3; metadata showing published October 31, 2019 and updated August 28, 2024, no byline, with promotion) writes: if the paste does not fully cover the surface of the component, heat cannot be removed effectively.
An article from an electronic parts store (Source 4; April 1, 2026, no byline, distributor’s statement, with promotion) writes: paste cannot fill a large gap of more than 0.1 mm, while a pad can fill the height differences between components.
An article from a PCB maker (Source 5; September 11, 2026, author named in the metadata alone, maker’s statement, with promotion) writes: for a very thin interface between two closely mating faces, paste is the more usable; when a defined gap has to be bridged, a pad is better; a pad that is too thin may leave an air gap.
A website article from a thermal materials company (Source 6; no date, no byline, maker’s statement, with promotion) writes: pad thickness is 0.2 to 20 mm and its applications are wide; paste as a gap-filling material is “limited” (Note Table 1).
Point 2 | Application and rework: a pad is easy to fit, paste is harder to apply, and statements on reuse after taking apart disagree
How to look at it:
Write down first: whether the part will be taken apart for service later, and whether the site can control the amount of paste applied.
Whether a removed pad can be reused: Sources 4 and 6 write that it can be fitted again, and Source 5 writes that it carries a risk; all are talking about reusing a removed pad, and the statements disagree.
Whether paste is easy to redo after taking apart: Source 1 writes it can be reworked easily, and Source 6 writes it is not easy to re-apply; Source 3 writes that the mess of paste makes later service difficult; all are talking about redoing or servicing paste, and the statements disagree.
What the public sources say:
Source 1 writes: a pad is easy to handle and simple to install, with less room for assembly error; paste is hard to apply, and spreading it evenly in manufacturing is often difficult; paste has high thermal conductivity and can also be reworked easily.
Source 2 writes: paste needs a lot of pressure to transfer heat effectively; a pad can be cut to an exact shape, is easy to apply, and is usually placed by hand.
Source 3 writes: paste is squeezed from a tube and is easy to apply on almost any product; when the product needs service later, the mess of paste makes the service difficult; a pad is supplied as sheet and can be die-cut to fit the component.
Source 4 writes: for ease of application, paste is “medium (needs skill)” and pad is “easy (cut and stick)”; for reuse, paste is “no (must be re-applied)” and pad is “yes (if not torn).”
Source 5 writes: a pad is “clean, reworkable, but the thickness has to be right”; reuse carries a risk, and the reason it gives is that a removed pad may tear, be contaminated, be permanently compressed, or no longer line up.
Source 6 writes: a pad can be cut freely, the protective film peeled off and stuck on directly, and it is easy to fit again; paste has to be spread out evenly with care, and is not easy to re-apply after taking apart (Note Table 2).
Point 3 | Insulation and mess: most pad types are insulating; paste depends on composition, and spill-out may get onto the surroundings
How to look at it:
Write down first: whether there are bare traces or contacts around.
Insulation has to be read from each model’s own specification: for pads, Sources 4 and 5 write “most types” and “many,” not every kind; Source 6 writes that a pad has good insulation.
Whether paste conducts electricity: the statements of Source 4 and Source 6 cover different ranges.
What the public sources say:
Source 1 writes: a pad does not dirty the environment; paste is messy and hard to apply.
Source 3 writes: paste is very messy.
Source 4 writes: “most types” of pads are electrically insulating; paste comes in non-conductive (ceramic) and high-performance (metal) versions.
Source 5 writes: many ceramic-filled silicone or acrylic pads are electrically insulating, but not every thermal pad is.
Source 6 writes: a pad has good insulation; paste has poor insulation, and the reason it gives is that metal powder is added; paste has to be spread with care, or it easily gets onto the surrounding components, causing short circuits and scratches (Note Table 3).
Point 4 | Thermal performance and long-term change: the sources say paste conducts heat better and a pad is more stable; some sources also remind readers not to look at thermal conductivity alone
How to look at it:
Write down first: compare the thermal resistance of the whole joint, not just the marked thermal conductivity.
Pump-out means the paste moving away from the contact surface under temperature cycling (Source 4); the lifetime in years and the thermal resistance figures come from Source 4 alone.
Thermal performance: Sources 2, 3, 4, and 6 write that paste is better; Source 5 reminds readers not to compare thermal conductivity alone.
What the public sources say:
Source 1 writes: paste has high thermal conductivity.
Source 2 writes: paste usually has ideal heat transfer performance; a pad has no risk of pump-out, which boards under rapid temperature cycling can run into; drying out is listed as a drawback of paste.
Source 3 writes: on the surface, paste conducts heat better than a pad, but a pad’s heat removal is much more consistent; at high temperature paste may liquefy and move, and then remove heat worse; a pad has no risk of degrading or moving inside the product.
Source 4 writes: for thermal resistance, paste 0.05 to 0.2 and pad 0.5 to 3.0 (unit °C·cm²/W); for lifetime, paste dries out in 3 to 5 years and pad is stable for 10 years or more; under temperature cycling paste pumps out and a pad does not.
Source 5 writes: do not change material just because the marked thermal conductivity is higher; compare the thermal impedance at the intended thickness and pressure; the amount of paste and pump-out must be controlled; the problems of a pad include aging, tearing, and pump-out of paste next to it.
Source 6 writes: at the same thermal conductivity, paste has the lower thermal resistance and works better; a pad needs a higher thermal conductivity to reach the same effect (Note Table 4).
Comparison table: the four points at a glance
| Item | Thermal paste | Thermal pad |
|---|---|---|
| Gap and thickness | The sources say a thin layer and a limited gap it can fill; one says it can fill a larger gap | The sources say it fills a larger gap; thickness figures differ by source |
| Application and rework | Harder to apply; statements on redoing it after taking apart disagree | Easy to fit; statements on reusing it after removal disagree |
| Insulation and mess | Depends on composition; spill-out may get onto the surroundings | Most types insulating |
| Thermal performance and long-term change | The sources say better conduction; may dry out or pump out | The sources say more stable; higher thermal resistance figures |
Sources: Note Tables 1 to 4 (Sources 1 to 6). These are the statements of each source, not selection thresholds.
How to choose: when to look at paste, and when at a pad
By the public sources, the two can be viewed like this (the sources’ statements divided into four situations; this is our own compilation):
When to look at thermal paste: the two faces mate closely and the interface is very thin (Sources 4, 5, 6); better thermal performance is wanted (Sources 2, 4, 6; Source 3 writes that it holds if the surface is fully covered (and not otherwise)); the site can control the amount and is not afraid of getting onto the surroundings (Sources 3, 6).
When to look at a thermal pad: the gap is larger or the heights of two places differ (Sources 4, 5, 6); easy fitting and a cleaner job are wanted (Sources 1, 3, 4, 6); there are bare traces around and insulation matters (Sources 4, 5, 6); drying out or pump-out is a worry (Sources 2, 3, 4).
Where to look carefully: whether paste can fill a larger gap, where the statement of Source 2 and those of Sources 4, 5, and 6 disagree; whether a removed pad can be reused, and whether paste is easy to redo or service after taking apart, where the sources disagree; insulation has to be read from each model’s own specification; the lifetime and thermal resistance figures come from Source 4 alone; all 6 sources are manufacturers, distributors, or website articles, with no neutral body’s direct comparison; Source 6 has no date.
Near the boundary: the gap is around a few tenths of a millimeter (the figures of Source 4: paste up to 0.1 mm, pad from 0.3 mm, with nothing written in between), or the two faces are uneven but there are bare traces around; the sources give no boundary, so go by the material maker’s data sheet.
This is what the public sources say, not a conclusion for your site; which kind to choose depends on your gap, heat load, and assembly method.
What Jiahon can offer
On the thermal paste side:
Thermal Heat Dissipation Paste: the page is marked “thermal paste” and “heat dissipation paste”; for price and stock, please ask.
On the thermal pad side:
Thermal Pad / Heat Dissipation Pad: the page is marked “thermal pad” and “heat dissipation pad”; for price and stock, please ask.
When the type needs to be matched, first prepare six items: the component to be cooled and its heat load; the gap between the two faces and their flatness (measured values); whether there are bare traces around and whether insulation is needed; whether the part will be taken apart for service later; the mounting pressure and operating temperature; and the material currently used and the problem met (temperature too high, drying out, spill-out).
Notes: sources and exceptions
This is for people who need to check; skipping it does not affect the method above. Where the material maker’s data sheet and the equipment’s instructions differ from this article, go by those.
Where each point comes from
| Source | Where it is used and where it comes from |
|---|---|
| Source 1 | Points 1, 2, 3, 4: the shared purpose and form of the pad, easy to fit and hard to apply, rework, mess, thermal conductivity. From a blog article of a precision die-cut parts company (Mari Inc.; October 8, 2014; personal byline; maker’s statement, with promotion, older) |
| Source 2 | Points 1, 2, 4: larger gap and thickness, pressure and hand placement, thermal conductivity, pump-out and drying out. From an article of a PCB design software company (Altium; created March 31, 2017, updated July 27, 2021; personal byline; with promotion) |
| Source 3 | Points 1, 2, 3, 4: coverage, spreading and service, mess, thermal conductivity and stability. From an article of a die-cut and component company (Cohesive Components; no visible date on the page, metadata showing published October 31, 2019 and updated August 28, 2024; no byline; with promotion) |
| Source 4 | Points 1, 2, 3, 4: figures for gap and thickness, ease of application and reuse, insulation, thermal resistance and lifetime, pump-out. From an article of an electronic parts store (zbotic; April 1, 2026; no byline; distributor’s statement, with promotion) |
| Source 5 | Points 1, 2, 3, 4: thin interface and known gap, rework and reuse, insulation, comparing thermal impedance. From an article of a PCB maker (BestPCBs; September 11, 2026 in the footer; author named in the metadata alone; maker’s statement, with promotion) |
| Source 6 | Points 1, 2, 3, 4: thickness and gap filling, cutting and re-fitting, insulation, thermal conductivity and thermal resistance. From a website article of a thermal materials company (T-Global; FAQ page; a Taiwan company; no date; no byline; maker’s statement, with promotion) |
| Jiahon material | “What Jiahon can offer.” From the names and wording of Jiahon’s product pages |
Note Table 1 | Gap and thickness
| Item | What the public sources say |
|---|---|
| Shared purpose and form | Both are used to fill the gap between a heat-generating component and a heat sink; a pad is a pre-formed rectangular or square solid material (Source 1) |
| Larger gap and thickness | Paste is liquid, and when the surface is uneven it can fill a larger gap more evenly than a pad; pads are almost all thicker than paste; the thinner the interface material layer, the better the heat conduction (Source 2) |
| Coverage | If the paste does not fully cover the surface of the component, heat cannot be removed effectively (Source 3) |
| Gap and thickness | Paste cannot fill a large gap of more than 0.1 mm, while a pad can fill the height differences between components; the table lists paste at most 0.1 mm and pad 0.3 mm to 5 mm or more (Source 4) |
| Thin interface and known gap | For a very thin interface between two closely mating faces, paste is the more usable; when a defined gap has to be bridged, a pad is better; a pad that is too thin may leave an air gap (Source 5) |
| Thickness and gap filling | Pad thickness is 0.2 to 20 mm and its applications are wide; paste as a gap-filling material is “limited” (Source 6) |
Sources: 1, 2, 3, 4, 5, 6.
Note Table 2 | Application and rework
| Item | What the public sources say |
|---|---|
| Application and rework | A pad is easy to handle and simple to install, with less room for assembly error; paste is hard to apply, and spreading it evenly in manufacturing is often difficult; paste has high thermal conductivity and can also be reworked easily (Source 1) |
| Pressure and placing | Paste needs a lot of pressure to transfer heat effectively; a pad can be cut to an exact shape, is easy to apply, and is usually placed by hand (Source 2) |
| Spreading and service | Paste is squeezed from a tube and is easy to apply on almost any product; when the product needs service later, the mess of paste makes the service difficult; a pad is supplied as sheet and can be die-cut to fit the component (Source 3) |
| Ease of application and reuse | For ease of application, paste is “medium (needs skill)” and pad is “easy (cut and stick)”; for reuse, paste is “no (must be re-applied)” and pad is “yes (if not torn)” (Source 4) |
| Rework and reuse | A pad is “clean, reworkable, but the thickness has to be right”; reuse carries a risk, and the reason it gives is that a removed pad may tear, be contaminated, be permanently compressed, or no longer line up (Source 5) |
| Cutting and re-fitting | A pad can be cut freely, the protective film peeled off and stuck on directly, and it is easy to fit again; paste has to be spread out evenly with care, and is not easy to re-apply after taking apart (Source 6) |
Sources: 1, 2, 3, 4, 5, 6.
Note Table 3 | Insulation and mess
| Item | What the public sources say |
|---|---|
| Mess | A pad does not dirty the environment; paste is messy and hard to apply (Source 1) |
| Mess | Paste is very messy (Source 3) |
| Insulation | “Most types” of pads are electrically insulating; paste comes in non-conductive (ceramic) and high-performance (metal) versions (Source 4) |
| Insulation | Many ceramic-filled silicone or acrylic pads are electrically insulating, but not every thermal pad is (Source 5) |
| Insulation and getting onto the surroundings | A pad has good insulation; paste has poor insulation, and the reason it gives is that metal powder is added; paste has to be spread with care, or it easily gets onto the surrounding components, causing short circuits and scratches (Source 6) |
Sources: 1, 3, 4, 5, 6.
Note Table 4 | Thermal performance and long-term change
| Item | What the public sources say |
|---|---|
| Thermal conductivity | Paste has high thermal conductivity (Source 1) |
| Thermal conductivity and pump-out | Paste usually has ideal heat transfer performance; a pad has no risk of pump-out, which boards under rapid temperature cycling can run into; drying out is listed as a drawback of paste (Source 2) |
| Thermal conductivity and stability | On the surface, paste conducts heat better than a pad, but a pad’s heat removal is much more consistent; at high temperature paste may liquefy and move, and then remove heat worse; a pad has no risk of degrading or moving inside the product (Source 3) |
| Thermal resistance and lifetime | Thermal resistance: paste 0.05 to 0.2, pad 0.5 to 3.0 (unit °C·cm²/W); lifetime: paste dries out in 3 to 5 years, pad is stable for 10 years or more; under temperature cycling paste pumps out (moves away from the contact surface) and a pad does not (Source 4) |
| How to compare, and problems | Do not change material just because the marked thermal conductivity is higher; compare the thermal impedance at the intended thickness and pressure; the amount of paste and pump-out must be controlled; the problems of a pad include aging, tearing, and pump-out of paste next to it (Source 5) |
| Thermal conductivity and thermal resistance | At the same thermal conductivity, paste has the lower thermal resistance and works better; a pad needs a higher thermal conductivity to reach the same effect (Source 6) |
Sources: 1, 2, 3, 4, 5, 6.
This is the general case; individual cases still have to be judged on their own.
Exceptions and limits
What we saw and what we did not see: What this article read is 1 blog article from a precision die-cut parts company (October 8, 2014, personal byline, maker’s statement, with promotion, older), 1 article from a PCB design software company (created March 31, 2017, updated July 27, 2021, personal byline, with promotion), 1 article from a die-cut and component company (no visible date, metadata showing published October 31, 2019 and updated August 28, 2024, no byline, with promotion), 1 article from an electronic parts store (April 1, 2026, no byline, distributor’s statement, with promotion), 1 article from a PCB maker (footer showing September 11, 2026, author named in the metadata alone, maker’s statement, ending with an invitation to send details for a quote), and 1 website article from a thermal materials company (no date, no byline, just the copyright year in the footer, maker’s statement, with promotion). All 6 sources are statements of manufacturers, distributors, or software companies; we found no neutral body’s direct comparison of thermal paste and thermal pad, and no text of a standard. Source 6 is an English page of a Taiwan thermal materials company and carries no price or supply data; we found no measured data for the two on the same assembly; an item that Note Tables 1 to 4 do not list was not seen in what was read, which does not mean the source text does not write it.
The figures in the text: The figures quoted are: pad thickness 0.2 to 20 mm (Source 6); paste at most 0.1 mm and pad 0.3 mm to 5 mm or more (Source 4); thermal resistance of paste 0.05 to 0.2 and pad 0.5 to 3.0 (unit °C·cm²/W), and lifetime of paste 3 to 5 years and pad 10 years or more (Source 4); and the dates of each article. Units follow the sources and were not converted by us.
Differences between sources: Whether paste can fill a larger gap: Source 2 writes that paste can fill a larger gap more evenly than a pad, Source 4 writes that paste cannot fill a large gap of more than 0.1 mm, Source 5 writes that for a thin interface between two closely mating faces paste is the more usable and when a defined gap has to be bridged a pad is better, and Source 6 writes that paste as a gap-filling material is limited; all are talking about the gap-filling ability of paste, and the statements disagree, with Source 2 giving no figure. Uneven surfaces: Source 2 writes paste is better, and Sources 5 and 6 write a pad is better; Source 5 is writing about which is better under different situations, and does not write that paste cannot fill. Pad thickness range: the figures of Source 4 (0.3 mm to 5 mm or more) and Source 6 (0.2 to 20 mm) differ, and are not converted. Whether a removed pad can be reused: Source 6 writes it is easy to fit again, Source 4 writes it can be reused if not torn, and Source 5 writes that reuse carries a risk; all are talking about reusing a removed pad, and the statements disagree. Whether paste is easy to redo after taking apart: Source 1 writes it can be reworked easily, Source 6 writes it is not easy to re-apply after taking apart, and Source 3 writes that the mess of paste makes later service difficult; all are talking about redoing or servicing paste, and the statements disagree. Whether paste conducts electricity: Source 6 writes that paste has poor insulation, and the reason it gives is that metal powder is added, while Source 4 writes that paste comes in non-conductive (ceramic) and high-performance (metal) versions; both are talking about whether paste conducts, and the ranges they cover differ. They are set side by side in the text, and not merged into one rule.
Single-source claims: the thermal resistance figures and lifetime in years (Source 4); paste’s poor insulation because of added metal powder (Source 6); paste needing a lot of pressure to transfer heat effectively (Source 2); comparing thermal impedance at the intended thickness and pressure (Source 5).
Sources with a stance: All 6 sources are statements of manufacturers, distributors, or software companies (Sources 1 to 6 all carry promotion); we found no neutral body’s direct comparison of thermal paste and thermal pad and no text of a standard, so the statements can be taken as illustrative examples. Source 1 is an older article (2014), so for products go by current data; the update date of Source 2 is 2021; Source 6 has no date.
The sources’ originals are in English: the wording here is our translation, not the sources’ own sentences; units follow what the sources wrote and were not converted by us.
Scope: Thermal paste here means what the sources call thermal paste (also written thermal grease); thermal pad means thermal pad; phase-change sheets and liquid gap-filler compounds are outside the scope; model-by-model comparison, price, and lead time are not covered; no standards were checked.
A selection summary: This article is a selection summary, not a system design, and does not replace the material maker’s data sheet; it relays the statements of public data and a way of thinking about selection, and does not write “which is better.” The gap, heat load, and assembly method go by the site and the maker’s data.
Equipment and products: “What Jiahon can offer” takes just the names and wording of the product pages, and does not quote the product pages’ specifications, thermal conductivity, insulation, or any “non-conductive” claim; for the price and stock of each model, please ask, and go by the data confirmed by sales.
Our own compilation: Each statement can be found in the sources in the notes. The “How to choose” section (which states at its start that it is our own compilation) divides the sources’ statements into “when to look at thermal paste,” “when to look at a thermal pad,” “where to look carefully,” and “near the boundary”; this is our own compilation, not the sources’ own sentences, and it states that the sources give no boundary for gap and conditions of use. The “how to look at it” points (the items to write down first) are a way of working, not source statements. The opening sentence, “Thermal paste is spread between two faces and pressed thin; a thermal pad is a pre-cut sheet. The sources say paste has better thermal performance and works as a thin layer, while a pad is easy to fit and can fill a larger gap,” is compiled from Sources 2, 3, 4, 6 (thermal performance), Sources 4, 5, 6 (gap and thin layer), and Sources 1, 3, 4, 6 (easy to fit); “whether the material is spread on and pressed thin, or cut first and pressed in” is summarized from the points; the scope statement is this article’s own explanation; the “few tenths of a millimeter” mentioned under “near the boundary” sets the two figures of Source 4 (paste up to 0.1 mm, pad from 0.3 mm) side by side and points out that nothing is written in between; this is compilation, not a source statement; the rows of the tables are compiled by point.