How much ice do I need?

Ice Bath Water Temperature Calculator

Don't own a chiller device to cool your ice bath? Use the calculator below to estimate how much ice you'll need to reach the desired temperature.

Please be aware that this calculator merely provides an estimated water temperature and does not take into account numerous factors such as ambient air temperature and insulation, which can be significant. However, this will help you determine the amount of ice you need.

This calculator will give you the minimum possible temperature that your ice bath setup can achieve; in reality, the temperature may be slightly higher.

Ice Bath Temperature Estimator

Select Metric (°C, kg, L) or Imperial Units (°F, lbs, Gallons). Information Icon
Enter the current temperature of the water. Common range: 2°C to 16°C. Information Icon
Enter the temperature of the ice. A typical freezer has ice at about -15°C, which is usually slightly above your freezer temperature. Information Icon
Enter the amount of ice in kilograms. Information Icon
Enter the volume of water in the bath in litres before adding ice. PeakMe Focus is about 250L at the recommended fill level (2/3rd full). Information Icon

Putting this calculator into use

Ice Bath Temperature Guide

Optimal Temperature Window

2°C to 16°C (35°F to 60°F): Ideal range for cold therapy benefits.
Target Temperature: Approximately 10°C (50°F) is recommended.

Ice Size Considerations

Small Ice Cubes
- Melt rapidly for quick cooling.
- Ideal for short, immediate use.
- May require frequent top-ups.

Large Ice Blocks

- Melt slowly, sustaining cooler temperatures for longer. Initial cooldown takes longer.
- Suited for extended sessions or sequential use.
- More effective for maintaining a steady temperature over time.

Stirring During the Ice Bath

Periodically stirring the water ensures even temperature distribution as the water near you will warm up gradually.

Frostbite Warning
Avoid excessive ice which can drop temperatures to dangerous levels.

Shopping for an Ice Bath? We recommend the PeakMe Focus Portable Ice Bath - Learn More.

Calculation Notes

Complete Ice Melt
Assumes all ice is fully melted and mixed into the water.

Heat Exchange
Does not account for external heat gain or loss.

Initial Temperature Accuracy
Accurate initial water and ice temperatures are crucial for a precise calculation.

Temperature Calculation Formula

The above calculator attempts to precisely calculate the final temperature of your ice bath. The calculation below represents the process used by the calculator to achieve the output values.

The balance of energy during the melting of ice and the subsequent temperature equalisation can be expressed by this formula with relative accuracy:

Final Temp = (m_water * c_water * (T_water - 0) + m_ice * c_ice * (0 - T_ice) + m_ice * L_f) / (m_water + m_ice * c_water)

Getting Technical

Calculation Explainer

Final Temp: The estimated final temperature of the mixture after all the ice has melted and the system has reached thermal equilibrium, in degrees Celsius (°C).

Constants & Units

  • c_water (4.186): The specific heat capacity of water in joules per gram per degree Celsius (J/g°C). This value indicates how much energy is needed to raise the temperature of 1 gram of water by 1°C.
  • m_water: The mass of the water in grams (g). This is the amount of water you're starting with.
  • T_water: The initial temperature of the water in degrees Celsius (°C).
  • c_ice (2.1): The specific heat capacity of ice in joules per gram per degree Celsius (J/g°C). It represents the amount of energy required to change the temperature of 1 gram of ice by 1°C, without changing its state.
  • m_ice: The mass of the ice in grams (g).
  • T_ice: The initial temperature of the ice in degrees Celsius (°C). Since ice is below 0°C, this value is often negative in practical situations.
  • 334: The latent heat of fusion of ice in joules per gram (J/g). This is the amount of energy required to convert 1 gram of ice at 0°C into 1 gram of water at 0°C, without changing its temperature.
  • ((m_water + m_ice) * c_water): This part of the formula calculates the total energy capacity of the mixture after all ice has melted, assuming the mixture's specific heat capacity is similar to that of water, which is a reasonable approximation.

How to Use the Formula

  1. Measure or estimate the masses of the ice and water you're using (in grams).
  2. Record the initial temperatures of both the ice and the water (in °C). Remember, ice temperature should be below 0°C, so it's typically a negative number.
  3. Plug these values into the formula to calculate the Final Temp, which will give you an approximation of the temperature after the ice has melted and mixed with the water.