Thermal Interface (TIM) Calculator
θ of any thermal paste, pad or liquid-metal joint from thickness, conductivity and area — and what it costs you in °C.
Thickness beats conductivity: halving the bond line helps as much as doubling k. Paste exists to fill ~10 µm machining valleys, not to be a layer — “more is better” is exactly wrong. Pads are convenient and insulating but 5–10× worse than thin paste; liquid metal is superb but conductive and corrodes aluminium — copper/nickel surfaces only.
Thermal Paste Calculator computes the thermal resistance of any interface material layer and the °C it costs — free, instant and private in your browser. PC builders, power-electronics designers and anyone choosing pad vs paste vs liquid metal use it to skip the datasheet algebra: type your numbers, read the answer with the substituted formula shown step by step, and share an exact permalink of the calculation.
About Thermal Interface (TIM) Calculator
Thermal Paste Calculator computes the thermal resistance of any interface material layer and the °C it costs using the standard engineering relation: θ = t/(k·A) — bond-line thickness over conductivity times contact area. Worked live: 50 µm of decent paste (4 W/mK) on a 15×15 mm tab adds just 0.06 °C/W; a 500 µm pad at 3 W/mK adds 0.74. The result recalculates on every keystroke, the worked-example panel shows your numbers substituted into the formula, and the Copy permalink button encodes the inputs in the URL so a colleague opens exactly your calculation. Everything runs client-side — nothing you type leaves your device.
How to use Thermal Interface (TIM) Calculator
- 1Enter your values — the tool starts with realistic defaults for this exact use case, so the worked example is meaningful immediately.
- 2Read the live result and the worked-example panel, which substitutes your numbers into the formula step by step.
- 3Adjust any input to compare scenarios, then use Copy result or Copy permalink to share the calculation.
Why use Thermal Interface (TIM) Calculator?
- ✓Implements the real formula — θ = t/(k·A) — bond-line thickness over conductivity times contact area — with the substitution shown, not a black box
- ✓Built for PC builders, power-electronics designers and anyone choosing pad vs paste vs liquid metal
- ✓Copy result and permalink buttons — share the exact calculation in a README, forum answer or design review
- ✓100% free, no sign-up, runs entirely in your browser (works offline once loaded)
Frequently asked questions
How do you calculate thermal paste?+
The thermal resistance of any interface material layer and the °C it costs follows θ = t/(k·A) — bond-line thickness over conductivity times contact area. For example, 50 µm of decent paste (4 W/mK) on a 15×15 mm tab adds just 0.06 °C/W; a 500 µm pad at 3 W/mK adds 0.74. The calculator applies the same relation and shows the substituted arithmetic so you can verify every step.
Is expensive thermal paste worth it?+
Less than thin application is. Halving bond-line thickness helps as much as doubling conductivity — paste should fill microscopic valleys, not form a layer. The difference between a 4 and 12 W/mK paste applied properly is typically 1–3 °C on a CPU.
When must I use a pad instead of paste?+
When you need electrical isolation (TO-220 tab to grounded sink), gap-filling across uneven heights, or assembly without mess. Accept 5–10× the interface resistance of thin paste, and pick pad thickness as the MINIMUM that fills your gap.
Is the Thermal Paste Calculator free and private?+
Yes — completely free with no sign-up or usage limits, and it runs entirely in your browser: the values you enter are never uploaded or stored on a server.
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