Specific Heat Capacity Water
Reference data and engineering information about specific heat capacity water for thermodynamics applications.
Overview
Water has one of the highest specific heat capacities of any common substance, which makes it an excellent heat transfer and thermal storage medium. The isobaric specific heat (Cp) is most commonly used in open or constant-pressure systems such as building heating, while isochoric specific heat (Cv) applies to closed, constant-volume systems.
The values below are given at saturation pressure, which is effectively atmospheric pressure for temperatures below 100 °C.
Original Source Text and Calculator Basis
The source describes specific heat as the amount of heat required to change the temperature of a unit mass by one degree. For water it presents both isochoric specific heat and isobaric specific heat, with values tabulated by temperature in SI and Imperial units. The restored tables below preserve the Celsius and Fahrenheit source data, including the high-temperature saturated-liquid range.
The "Heat Required to Warm Water" calculator is derived directly from the source heat-capacity relationship:
heat = mass * specific heat * temperature change
It is an interactive form of the same engineering use case as the source calculator and the restored specific-heat tables.
Key Formulas
Heat absorbed or released:
Q = m * Cp * ΔT
Temperature change for a known heat input:
ΔT = Q / (m * Cp)
Variables
| Symbol | Meaning | Typical SI Unit |
|---|---|---|
| Q | Heat transferred | J or kJ |
| m | Mass of water | kg |
| Cp | Isobaric specific heat capacity | kJ/(kg·K) |
| Cv | Isochoric specific heat capacity | kJ/(kg·K) |
| ΔT | Temperature change | K or °C |
Isobaric Specific Heat (Cp) — Liquid Water
The Cp of water reaches a minimum near 35–40 °C and rises on either side. This behaviour matters when sizing heat exchangers and boilers.
Temperature(°C) | Cp(kJ/(kg·K)) | Cp(kcal/(kg·K)) |
|---|---|---|
| 0 | 4.2199 | 1.0073 |
| 10 | 4.1955 | 1.001 |
| 20 | 4.1844 | 0.9929 |
| 30 | 4.1801 | 0.9834 |
| 40 | 4.1796 | 0.973 |
| 50 | 4.1815 | 0.9617 |
| 60 | 4.1851 | 0.9498 |
| 70 | 4.1902 | 0.9375 |
| 80 | 4.1969 | 0.925 |
| 100 | 4.2157 | 0.9 |
| 120 | 4.2435 | 0.8757 |
| 140 | 4.2826 | 0.8525 |
| 160 | 4.3354 | 0.8309 |
Source: engineeringtoolbox.com
Isochoric Specific Heat (Cv) — Liquid Water
Temperature(°C) | Cv(kJ/(kg·K)) | Cv(J/(mol·K)) |
|---|---|---|
| 0 | 4.2174 | 75.981 |
| 10 | 4.191 | 75.505 |
| 20 | 4.157 | 74.893 |
| 30 | 4.1175 | 74.181 |
| 40 | 4.0737 | 73.392 |
| 50 | 4.0264 | 72.54 |
| 60 | 3.9767 | 71.644 |
| 80 | 3.8729 | 69.774 |
| 100 | 3.7682 | 67.888 |
| 120 | 3.6662 | 66.05 |
| 140 | 3.5694 | 64.306 |
| 160 | 3.4788 | 62.674 |
Source: engineeringtoolbox.com
Cp vs Temperature
Isobaric Specific Heat of Water vs Temperature
Water Specific Heat vs Temperature - Fahrenheit
Calculator
Heat Required to Warm Water
Online Water Specific Heat Calculator
The original source included an online water specific heat calculator. This migrated version returns Cp and Cv for liquid water by interpolation over the restored source table. For a quick interactive approximation, enter temperature in Celsius and use the quadratic fits below for the normal liquid range; detailed tabulated values remain available in the restored source tables.
Online Water Specific Heat Calculator
Unit Converter
Specific Heat Unit Converter
Restored Original Source Tables
The following tables are restored from the original source page to preserve the complete reference data.
Water - Specific Heat vs. Temperature
°C(°C) | J/(mol K)(J/(mol K)) | kJ/kgK(kJ/kgK) | kWh/(kg K)(kWh/(kg K)) | kcal/(kg K)) (Btu(IT)/lbm °F(kcal/(kg K)) (Btu(IT)/lbm °F) | J/(mol K)(J/(mol K)) | kJ/kgK(kJ/kgK) | kWh/(kg K)(kWh/(kg K)) | kcal/(kg K)) (Btu(IT)/lbm °F(kcal/(kg K)) (Btu(IT)/lbm °F) |
|---|---|---|---|---|---|---|---|---|
| 0.01 | 75.981 | 4.2174 | 0.001172 | 1.0073 | 76.026 | 4.2199 | 0.001172 | 1.0079 |
| 10 | 75.505 | 4.191 | 0.001164 | 1.001 | 75.586 | 4.1955 | 0.001165 | 1.0021 |
| 20 | 74.893 | 4.157 | 0.001155 | 0.9929 | 75.386 | 4.1844 | 0.001162 | 0.9994 |
| 25 | 74.548 | 4.1379 | 0.001149 | 0.9883 | 75.336 | 4.1816 | 0.001162 | 0.9988 |
| 30 | 74.181 | 4.1175 | 0.001144 | 0.9834 | 75.309 | 4.1801 | 0.001161 | 0.9984 |
| 40 | 73.392 | 4.0737 | 0.001132 | 0.973 | 75.3 | 4.1796 | 0.001161 | 0.9983 |
| 50 | 72.54 | 4.0264 | 0.001118 | 0.9617 | 75.334 | 4.1815 | 0.001162 | 0.9987 |
| 60 | 71.644 | 3.9767 | 0.001105 | 0.9498 | 75.399 | 4.1851 | 0.001163 | 0.9996 |
| 70 | 70.716 | 3.9252 | 0.00109 | 0.9375 | 75.491 | 4.1902 | 0.001164 | 1.0008 |
| 80 | 69.774 | 3.8729 | 0.001076 | 0.925 | 75.611 | 4.1969 | 0.001166 | 1.0024 |
| 90 | 68.828 | 3.8204 | 0.001061 | 0.9125 | 75.763 | 4.2053 | 0.001168 | 1.0044 |
| 100 | 67.888 | 3.7682 | 0.001047 | 0.9 | 75.95 | 4.2157 | 0.001171 | 1.0069 |
| 110 | 66.96 | 3.7167 | 0.001032 | 0.8877 | 76.177 | 4.2283 | 0.001175 | 1.0099 |
| 120 | 66.05 | 3.6662 | 0.001018 | 0.8757 | 76.451 | 4.2435 | 0.001179 | 1.0135 |
| 140 | 64.306 | 3.5694 | 0.000992 | 0.8525 | 77.155 | 4.2826 | 0.00119 | 1.0229 |
| 160 | 62.674 | 3.4788 | 0.000966 | 0.8309 | 78.107 | 4.3354 | 0.001204 | 1.0355 |
| 180 | 61.163 | 3.3949 | 0.000943 | 0.8109 | 79.36 | 4.405 | 0.001224 | 1.0521 |
| 200 | 59.775 | 3.3179 | 0.000922 | 0.7925 | 80.996 | 4.4958 | 0.001249 | 1.0738 |
| 220 | 58.514 | 3.2479 | 0.000902 | 0.7757 | 83.137 | 4.6146 | 0.001282 | 1.1022 |
| 240 | 57.381 | 3.185 | 0.000885 | 0.7607 | 85.971 | 4.7719 | 0.001326 | 1.1397 |
| 260 | 56.392 | 3.1301 | 0.000869 | 0.7476 | 89.821 | 4.9856 | 0.001385 | 1.1908 |
| 280 | 55.578 | 3.0849 | 0.000857 | 0.7368 | 95.285 | 5.2889 | 0.001469 | 1.2632 |
| 300 | 55.003 | 3.053 | 0.000848 | 0.7292 | 103.6 | 5.7504 | 0.001597 | 1.3735 |
| 320 | 54.819 | 3.0428 | 0.000845 | 0.7268 | 117.78 | 6.5373 | 0.001816 | 1.5614 |
| 340 | 55.455 | 3.0781 | 0.000855 | 0.7352 | 147.88 | 8.208 | 0.00228 | 1.9604 |
| 360 | 59.402 | 3.2972 | 0.000916 | 0.7875 | 270.31 | 15.004 | 0.004168 | 3.5836 |
Source: engineeringtoolbox.com
Water - Specific Heat vs. Temperature
°F(°F) | Btu(IT)/(mol °R)(Btu(IT)/(mol °R)) | Btu(IT)/(lbm °F)) (kcal/(kg K)(Btu(IT)/(lbm °F)) (kcal/(kg K)) | kJ/kgK(kJ/kgK) | Btu(IT)/kmol °R(Btu(IT)/kmol °R) | Btu(IT)/lbm °F) (kcal/kg K(Btu(IT)/lbm °F) (kcal/kg K) | kJ/kg K(kJ/kg K) |
|---|---|---|---|---|---|---|
| 32.2 | 40 | 1.007 | 4.217 | 40.032 | 1.008 | 4.22 |
| 40 | 39.9 | 1.005 | 4.208 | 39.916 | 1.005 | 4.208 |
| 50 | 39.8 | 1.001 | 4.191 | 39.801 | 1.002 | 4.196 |
| 60 | 39.6 | 0.996 | 4.169 | 39.739 | 1.001 | 4.189 |
| 80 | 39.2 | 0.986 | 4.128 | 39.66 | 0.999 | 4.181 |
| 100 | 38.7 | 0.975 | 4.082 | 39.643 | 0.998 | 4.179 |
| 120 | 38.3 | 0.963 | 4.033 | 39.662 | 0.999 | 4.181 |
| 140 | 37.7 | 0.95 | 3.977 | 39.702 | 1 | 4.185 |
| 160 | 37.2 | 0.937 | 3.923 | 39.761 | 1.001 | 4.191 |
| 180 | 36.7 | 0.923 | 3.865 | 39.835 | 1.003 | 4.199 |
| 200 | 36.1 | 0.909 | 3.805 | 39.927 | 1.005 | 4.209 |
| 212 | 35.7 | 0.9 | 3.768 | 39.993 | 1.007 | 4.216 |
| 220 | 35.5 | 0.895 | 3.745 | 40.042 | 1.008 | 4.221 |
| 240 | 35 | 0.88 | 3.686 | 40.186 | 1.012 | 4.236 |
| 260 | 34.4 | 0.867 | 3.629 | 40.364 | 1.016 | 4.255 |
| 280 | 33.9 | 0.854 | 3.574 | 40.58 | 1.022 | 4.278 |
| 300 | 33.4 | 0.841 | 3.522 | 40.838 | 1.028 | 4.305 |
| 350 | 32.3 | 0.813 | 3.404 | 41.685 | 1.05 | 4.394 |
| 400 | 31.3 | 0.789 | 3.302 | 42.902 | 1.08 | 4.522 |
| 450 | 30.4 | 0.767 | 3.209 | 44.009 | 1.108 | 4.639 |
| 500 | 29.7 | 0.748 | 3.13 | 47.296 | 1.191 | 4.986 |
| 550 | 28.8 | 0.725 | 3.035 | 51.318 | 1.292 | 5.41 |
| 600 | 28.3 | 0.713 | 2.987 | 59.69 | 1.503 | 6.292 |
| 625 | 28.4 | 0.716 | 2.997 | 66.611 | 1.677 | 7.022 |
| 650 | 28.9 | 0.728 | 3.047 | 82.851 | 2.086 | 8.734 |
| 675 | 29.9 | 0.754 | 3.156 | 126.67 | 3.189 | 13.353 |
Source: engineeringtoolbox.com
Original Source Images
The following original source images are preserved to avoid losing visual reference material. When an image contains chart or tabular data, its extracted values are represented in the page tables, calculators, or interactive charts; remaining images are retained as visual source references.
Engineering Notes
- Use Cp for most HVAC and plumbing calculations. Constant-pressure conditions dominate open tanks, piping, and heat exchangers on the water side.
- Cv decreases monotonically with temperature, while Cp has a shallow minimum around 35–40 °C.
- Above 100 °C the values are for pressurised (saturated) liquid water. Ensure the system pressure exceeds saturation pressure at the working temperature.
- For quick estimates a constant Cp of 4.18 kJ/(kg·K) is often assumed, which introduces less than 1 % error between roughly 10 °C and 60 °C.
- Valid input ranges for interpolation: 0–370 °C / 32–700 °F.