Heat Capacity Calculator
Use this calculator to solve any variable in the heat transfer equation Q = mc DeltaT. Select what you want to find, enter the remaining three values, and pick from 50+ material presets or type your own specific heat. Unit switches cover kilograms, grams, pounds, Celsius, Fahrenheit, Kelvin, Joules, kilojoules, calories, and BTU.
Formula
Worked example
How much heat is needed to warm 500 g of water from 20 °C to 100 °C? Q = 0.5 kg * 4186 J/(kg*K) * 80 K = 167,440 J = 167.4 kJ. The heat capacity of that cup of water is 0.5 * 4186 = 2093 J/K.
What is specific heat capacity?
Specific heat capacity (c) is the amount of heat energy required to raise the temperature of one kilogram of a substance by one Kelvin (or one degree Celsius). Water has one of the highest specific heats of common substances at 4,186 J/(kg*K), which is why it is used as a coolant, why oceans moderate coastal climates, and why a cup of tea stays hot for a long time. Metals like copper (385 J/(kg*K)) or gold (129 J/(kg*K)) have much lower values, so they heat up and cool down rapidly. The unit can also be written J/(kg*°C) because the size of a Kelvin and a Celsius degree are equal - only the zero point differs.
The heat transfer formula Q = mc DeltaT
The fundamental equation linking heat, mass, and temperature is Q = m * c * DeltaT, where Q is the heat transferred in joules, m is the mass in kilograms, c is the specific heat in J/(kg*K), and DeltaT is the change in temperature in Kelvin or Celsius. Rearranging gives you the other three variables: m = Q / (c * DeltaT) to find the mass needed, DeltaT = Q / (m * c) to find how much the temperature changes, and c = Q / (m * DeltaT) to measure an unknown material. Heat capacity of the whole sample (C, capital C) is simply m * c, giving the total joules needed per degree of temperature change without dividing by mass.
Difference between heat capacity and specific heat
Specific heat (c, lowercase) is an intrinsic property of the material independent of how much of it you have - water is always about 4,186 J/(kg*K) whether you are heating a drop or a lake. Heat capacity (C, uppercase) is an extrinsic property of a particular object and depends on both the material and the amount: C = m * c. A 2 kg pot of water has a heat capacity of 2 * 4,186 = 8,372 J/K, meaning it needs 8,372 joules to warm by 1 K, while a 0.1 kg sample needs only 419 J/K. This calculator reports both: the specific heat from your material choice, and the total heat capacity of your sample.
Practical applications of heat capacity
Heat capacity appears in everyday engineering and science. In cooking, cast iron (low c) heats quickly and holds temperature well under a cold food load; aluminum pans (c = 897 J/(kg*K)) heat even faster. In climate science, the oceans absorb and store enormous amounts of solar energy because of water's high specific heat, damping temperature swings. In building design, materials with high heat capacity (concrete, brick) act as thermal mass, absorbing heat during the day and releasing it at night to stabilize indoor temperatures. In electronics, heat sinks made from aluminum or copper transfer heat away from chips rapidly because their specific heats allow them to absorb bursts of energy without overheating.
Specific heat capacity of common materials
| Material | Specific heat c (J/kg*K) | Notes |
|---|---|---|
| Water (15 °C) | 4,186 | Highest of common liquids |
| Ammonia (liquid) | 4,700 | Used in refrigeration |
| Hydrogen (gas) | 14,300 | Highest of common gases |
| Ethanol | 2,440 | Organic solvent |
| Ice (-10 °C) | 2,090 | Lower than liquid water |
| Wood (typical) | 1,700 | Varies with species |
| Air (25 °C) | 1,005 | At constant pressure |
| Aluminum | 897 | Common lightweight metal |
| Glass (window) | 840 | Silica-based |
| Concrete | 880 | Building material |
| Iron / Steel | 449 | Structural metal |
| Copper | 385 | Excellent conductor |
| Zinc | 388 | Galvanizing metal |
| Tin | 228 | Soft metal |
| Silver | 235 | Precious metal |
| Gold | 129 | Dense precious metal |
| Lead | 128 | Very dense, low c |
| Mercury | 140 | Liquid at room temp |
| Tungsten | 134 | Highest melting point metal |
Values at approximately 25 °C and 1 atm unless noted. Sources: NIST and standard physics references.
Frequently asked questions
What is the specific heat of water?
Water has a specific heat capacity of about 4,186 J/(kg*K) at 15 °C, which is among the highest of all common substances. This high value is why water is so effective as a coolant and why oceans and large lakes moderate local climates. Ice and steam have lower specific heats (about 2,090 and 2,010 J/(kg*K) respectively), because the molecular structure and bonding change with phase.
What is the difference between Q, C, and c?
Q (or q) is the heat transferred in joules - it is an amount of energy, not a material property. c (lowercase) is the specific heat capacity of the material in J/(kg*K) - it does not depend on how much material you have. C (uppercase) is the heat capacity of a specific sample in J/K, equal to mass times specific heat (C = m * c). Saying "the specific heat of water is 4,186" means one kilogram of water needs 4,186 joules per degree; saying "the heat capacity of my 500 g sample is 2,093 J/K" tells you how many joules that exact sample needs.
Does specific heat change with temperature?
Yes, specific heat is not perfectly constant. For most solids and liquids it changes only slightly over normal temperature ranges, so the textbook values (like 4,186 J/(kg*K) for water) are good enough for most engineering calculations. Water's specific heat actually varies from about 4,218 J/(kg*K) near 0 °C to 4,179 J/(kg*K) at 40 °C, a range of less than 1%. For gases, the specific heat can vary more significantly with temperature, and two values are defined - at constant pressure (Cp) and at constant volume (Cv).
What units does this calculator support?
For heat energy: joules (J), kilojoules (kJ), calories (cal), kilocalories (kcal), BTU, and watt-hours (Wh). For mass: kilograms (kg), grams (g), pounds (lb), and ounces (oz). For temperature change: Celsius (°C), Fahrenheit (°F), and Kelvin (K). Note that a temperature change in Fahrenheit converts to Kelvin by multiplying by 5/9, while changes in Celsius and Kelvin are numerically equal.
How do I use this to find the specific heat of an unknown material?
Set "Solve for" to "Specific heat capacity (c)". Then enter the heat energy you applied (Q), the mass of the sample (m), and the temperature change you measured (DeltaT). The result is c in J/(kg*K). This is how calorimetry experiments work in a lab: you heat or cool a known mass by a measured temperature change and record the energy input to identify or verify a material's thermal properties.
Why does water have such a high specific heat?
Water molecules form hydrogen bonds with each other. When you add heat, much of the energy goes into breaking and re-forming these hydrogen bonds rather than raising the kinetic energy of the molecules (which is what temperature measures). That extra energy storage means water needs more energy per kilogram per degree than most substances. This is why water is so useful as a coolant, thermal buffer, and heat-storage medium.