Calculator
Saved calculations
| Timestamp | Solved for | Inputs | Result | Heat flux (W/m²) | R (K/W) |
|---|---|---|---|---|---|
| No saved runs yet. | |||||
Formula used
This tool uses the one‑dimensional, steady‑state conduction form of Fourier’s law:
- Q = heat transfer rate (W)
- k = thermal conductivity (W/m·K)
- A = cross‑sectional area (m²)
- ΔT = temperature difference across thickness (K)
- L = thickness along heat flow (m)
Assumptions: steady conditions, uniform material, 1‑D heat flow, negligible contact resistance, and constant properties over the temperature range.
How to use this calculator
- Select what you want to solve for (k, Q, L, A, or ΔT).
- Enter the remaining known values and choose their units.
- Use a temperature difference across the material thickness.
- Press Submit to view results below the header.
- Optionally save runs, then export CSV or PDF.
Example data table
Sample runs showing typical lab-style inputs and computed conductivity.
| Q | L | A | ΔT | Computed k |
|---|---|---|---|---|
| 12 W | 0.02 m | 0.01 m² | 15 K | 1.6 W/m·K |
| 35 W | 0.01 m | 0.02 m² | 20 K | 0.875 W/m·K |
| 90 W | 0.005 m | 0.03 m² | 10 K | 1.5 W/m·K |
Use your own measurements for reliable design decisions.
FAQs
1) What is thermal conductivity?
Thermal conductivity measures how easily heat moves through a material. Higher values mean faster heat transfer for the same area, thickness, and temperature difference.
2) Which equation does this tool apply?
It uses steady, one‑dimensional Fourier conduction: Q = (k·A·ΔT)/L. The tool rearranges this equation to solve for your selected unknown.
3) Can I calculate heat flow instead of conductivity?
Yes. Choose “Heat transfer rate (Q)” in the solve-for list, then provide k, A, L, and ΔT with their units.
4) Should I enter absolute temperatures or a difference?
Enter a temperature difference across the material. A difference in K equals a difference in °C. For °F differences, the tool converts automatically.
5) Why does my result look too large or too small?
Check unit selections, thickness direction, and measured area. Large contact resistance, edge losses, and non‑uniform heating can also distort steady‑state results.
6) Is this valid for transient heating?
No. This calculation assumes steady conditions. For transient cases you typically need thermal diffusivity and time‑dependent models, not just Fourier’s steady form.
7) How do exports work?
After you submit, the tool can save the run in a table. Use the Download CSV or Download PDF buttons to export your saved calculations.
8) What measurement tips improve accuracy?
Measure thickness along heat flow, use the true contact area, and stabilize temperatures before recording ΔT. Insulate edges and minimize convection to reduce losses.