Water Cooling Calculator
Calculate the required ice mass to drop water from one temperature to another, accounting for partial melting and ice temperature.
1 gallon ≈ 3.785 liters.
Target must be lower than initial temperature.
Use negative values if ice is below freezing (freezer at -10°C).
If some ice remains after cooling, use 0.8–0.9 to reduce required ice mass.
Ice required
0.94 kg
2.07 lb
Water volume
5.0 L
1.32 gallons
Heat removed
313.9 kJ
Cooling power ~0.17 kW (30 min)
Application tips
- Stir water regularly to equalize temperature and speed cooling.
- Use sealed ice packs if dilution is a concern (drinks, aquariums).
- Account for melting losses—keep extra ice on hand for warm environments.
How to Use This Calculator
Measure water volume & temperature
Use liters for volume; convert gallons by multiplying by 3.785.
Set target temperature
Choose the final temperature needed for beverages, hydroponics, or cooling baths.
Apply calculated ice
Scatter ice evenly and monitor temperature. Repeat calculation if adding more warm water.
Formula
mwater × c × (Tinitial − Ttarget) = mice × [fraction × L + c × (0 − Tice)]
where c = 4.186 kJ/kg°C and L = 334 kJ/kg
Example: 5 L water from 25°C → 10°C with 0°C ice, all melted → 5 × 4.186 ×15 / 334 ≈ 0.94 kg ice.
Tip: For imperial units, 1 lb ice removes ~144 BTU when fully melted.
Full Description
Cooling water quickly is essential for beverage service, aquaculture, brewing, and lab work. This calculator balances heat energy between warm water and cold ice to estimate how much ice you need for a specific temperature drop. Adjust for ice below freezing or cases where not all ice melts.
Combine the calculation with insulation strategies—ice chests, coolers, or circulation—to reduce ice consumption and keep temperatures stable.
Frequently Asked Questions
What if my ice is below 0°C?
The calculator accounts for sub-freezing ice—enter the ice temperature (e.g., -10°C) to include warming energy.
Can I mix in cold water instead of ice?
Yes—replace ice mass with cold water mass and omit the latent heat term in the equation.
How do I handle beverages in bottles?
Estimate beverage volume plus melted ice water; the calculator approximates total liquid needing cooling.
Why doesn’t all ice melt?
If target temperature is near 0°C, some ice may remain. Use fraction < 1 to reflect partial melting and reduce ice mass.