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Specific Heat Calculator

Computes the heat energy needed to change the temperature of a mass of material by a given amount from Q = m·c·ΔT, using the specific heat capacity of liquid water (4186 J/(kg·K)) by default.

When to use

You need how much energy heats or cools a known mass of water, metal or another substance by a given number of degrees, without a phase change.

Do not use when: The substance melts, boils or freezes within the range (latent heat is not included), or you need the final temperature when two bodies are mixed (calorimetry is not implemented).

Formula

heat_j = mass_kg × specific_heat_j_kg_k × temperature_change_k; kJ = J / 1000; kcal = J / 4184; kWh = J / 3,600,000

Assumes a constant specific heat over the temperature range and no phase change; water's value varies by under 1 % between 0 and 100 °C.

Inputs

Parameter	Type	Unit	Required	Description
`mass_kg`	number	kg	yes	Mass of the substance in kilograms (1 L of water ≈ 1 kg). Range: > 0
`specific_heat_j_kg_k`	number	J/(kg·K)	default 4186	Specific heat capacity: water 4186, ice 2090, steam 2010, aluminium 897, iron 449, copper 385, air ≈ 1005, ethanol 2440. Range: > 0
`temperature_change_k`	number	K	yes	Temperature rise in kelvin (identical to the °C difference); negative when the substance cools and releases heat.

Outputs

Output	Type	Unit	Description
`heat_j`	number	J	Q = m × c × ΔT; negative means heat released.
`heat_kj`	number	kJ	Heat in kilojoules.
`heat_kcal`	number	kcal	Heat in kilocalories (thermochemical calorie, 4184 J).
`heat_kwh`	number	kWh	Heat in kilowatt-hours (J ÷ 3,600,000).

Example

Heat 2 kg of water by 30 K: {"mass_kg":2,"temperature_change_k":30} → {"heat_j":251160,"heat_kj":251.16,"heat_kcal":60.0287,"heat_kwh":0.069767}

Heat 0.5 kg of aluminium (897) by 50 K: {"mass_kg":0.5,"specific_heat_j_kg_k":897,"temperature_change_k":50} → {"heat_j":22425,"heat_kj":22.425,"heat_kcal":5.3597}

GET https://tttkmbb.com/api/v1/calculate/specific-heat?mass_kg=2&temperature_change_k=30

Machine access

API: GET https://tttkmbb.com/api/v1/calculate/specific-heat (query parameters) or POST with a JSON body {"inputs": {...}}
Schema: https://tttkmbb.com/api/v1/calculators/specific-heat · Markdown: https://tttkmbb.com/physics/specific-heat.md · JSON definition: https://tttkmbb.com/physics/specific-heat.json
MCP: server https://tttkmbb.com/mcp, tool run_calculator with calculator_id="specific-heat"
OpenAPI operationId: calculate_specific_heat_energy
Freshness: static. Authentication: none. Rate limit: fair use (see rate limits).

Sources

HyperPhysics – Specific heat (reference)
Wikipedia – Table of specific heat capacities (reference)
NIST Special Publication 811 – Guide for the Use of the SI, Appendix B (conversion factors) (standard)

FAQ

Is a temperature change in °C the same as in K?

Yes. A difference of 30 °C is a difference of 30 K, so ΔT can be entered from Celsius readings directly.

How long does heating take with a given heater?

Divide the heat in joules by the heater power in watts: 251,160 J with a 2000 W kettle takes about 126 s at 100 % efficiency.

Related calculators

Electric Power Calculator — Energy delivered by an electric heater over time.
Energy Converter — Convert the result between J, kcal, kWh and BTU.
Temperature Converter — Convert temperatures between °C, °F and K.