Newton's Law of Cooling Calculator

Free Newton's Law of Cooling Calculator solves T(t) = T_env + (T₀ − T_env)·e^(−k·t) for any variable.

844.1K uses Updated · 2026-05-12 Runs locally · zero upload
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How to Use Newton’s Law of Cooling Calculator

  1. Pick the variable to solve for — T(t), t, k, T₀, or T_env.
  2. Enter the four known values with consistent units.
  3. Read the answer in the result panel.

Formula & Theory - Newton’s Law of Cooling Calculator

dT/dt = − k · ( T − T_env )

Integrated form:
  T(t) = T_env + ( T₀ − T_env ) · exp(−k · t)

Inverse for t:
  t = − ln[(T(t) − T_env) / (T₀ − T_env)] / k

Inverse for k:
  k = − ln[(T(t) − T_env) / (T₀ − T_env)] / t
SymbolMeaning
T(t)Temperature at time t
T₀Initial temperature
T_envAmbient temperature
kCooling constant (1/time)
tElapsed time

Assumptions and Limits

  • Lumped-capacitance: object has uniform internal temperature (small Biot number).
  • Constant T_env and constant k over the interval.
  • Convection dominates; radiation is negligible.

Use Cases for Newton’s Law of Cooling Calculator

  • Forensics — Estimate time of death from body temperature decay.
  • Food safety — Predict cooling time of cooked food to safe storage.
  • Engineering — Quick check of quench or warm-up curves.

The Newton’s Law of Cooling Calculator rearranges the exponential model for any unknown.

Frequently asked questions about Newton's Law of Cooling Calculator

What is Newton's law of cooling?

An object's rate of cooling is proportional to the difference between its temperature and the ambient temperature. The Newton's Law of Cooling Calculator integrates this to an exponential decay.

What is the cooling constant k?

A lumped coefficient (1/time) that depends on convection coefficient, surface area, mass and specific heat: k = h·A / (m·c).

Does the equation work for heating?

Yes — if T₀ < T_env the object heats up toward T_env; the same formula applies.

Is my data stored?

No. All calculations happen in your browser; nothing is sent to a server.