Ice vs Heat Calculator
Determine whether to use ice, heat, or both based on injury type, days since injury, and swelling status.
About this calculator
This calculator decides an ice-and-heat regimen — minutes of each per session, how often, and a named protocol — using a decision tree rather than a formula. Injury Type picks the tree: acute injuries and post-surgical cases both walk through time-based phases, while chronic injuries skip the timeline entirely and always get the same contrast prescription (heat 20 minutes before activity to loosen, ice 10 or 15 minutes after, depending on swelling). Within the acute tree, Days Since Injury/Surgery gates three phases — the first 72 hours are ice-only at 20 minutes every 2-3 hours (RICE), days 4-7 cut ice to 15 minutes and tentatively add 10 minutes of heat, and past day 7 the emphasis flips to 15 minutes of heat before activity with 10 of ice after. Post-surgery follows the same shape on a slower clock, holding ice-only through day 5 and keeping heat at zero until day 14.
Swelling Present is the tie-breaker inside the transition windows: any reported swelling zeroes the heat minutes and locks the protocol text to ice-only, since heat increases blood flow into already-inflamed tissue. Outside those transition windows, swelling changes nothing. The tool does not weigh injury location, skin sensitivity, or circulatory conditions that contraindicate both therapies.
Medical Disclaimer
This calculator is for informational and educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making decisions about your health. Never disregard professional medical advice or delay seeking it because of results from this tool.
Inputs
Results
Ice Duration
20 min
Heat Duration
0 min
How to Use This Calculator
- Select Injury Type: Acute (new injury), Chronic (recurring), or Post-Surgery.
- Enter Days Since Injury/Surgery.
- Select whether Swelling Present is No or Yes.
- Review Ice Duration (min) and Heat Duration (min).
- Use Frequency and Protocol to inform your decision.
What each input means
- Injury Type
- Classification of your injury
- Days Since Injury/Surgery
- Number of days since the injury or surgery occurred
- Swelling Present
- Is there visible swelling around the injury site
How this is calculated
Worked example, using the default values
- Identify Input ParametersInjury Type = 1, Days Since Injury/Surgery = 2, Swelling Present = 1 = 3 input(s) provided
- Calculate Ice DurationIce Duration20 = 20
- Calculate Heat DurationHeat Duration0 = 0
- Calculate FrequencyFrequencyEvery 2-3 hours = Every 2-3 hours
Engine last updated . Checked against 4 independently-derived tests — how we verify calculators. Built by Paul Gunder, a software engineer, not a licensed financial, medical, or legal professional.
Frequently Asked Questions
Why does my heat recommendation show zero minutes?
Either you are inside an ice-only window — the first 72 hours of an acute injury or the first 5 days after surgery — or you reported swelling during a transition phase. Swelling Present set to Yes forces Heat Duration to 0 in the day 4-7 acute and day 6-14 post-surgery windows, because heat increases blood flow into inflamed tissue.
Does the number of days matter for a chronic injury?
No. The chronic branch ignores Days Since Injury/Surgery completely and always prescribes the same routine: 20 minutes of heat before activity plus 10-15 minutes of ice after. The day count only drives the phase logic for acute and post-surgical injuries.
What's the difference between the acute and post-surgery timelines?
Same shape, different clock. Acute injuries hold ice-only for 3 days and begin adding heat from day 4; post-surgery holds ice-only for 5 days and begins adding heat from day 6. Whether that added heat actually shows nonzero minutes still depends on Swelling Present in both timelines — with the default "Yes," heat stays at zero through day 14 in the post-surgery branch (day 15 onward it's 15 minutes) and through day 7 in the acute branch; with "No," heat begins as soon as the ice-only window ends. Post-surgical frequency is also higher early on — every 2 hours while awake versus every 2-3 hours.
Why did my protocol flip back to ice-only when I changed only the swelling answer?
In the mid-timeline transition phases the engine treats swelling as a veto on heat. Days 4-7 of an acute injury normally allow a heat-then-ice contrast protocol, but selecting Yes for Swelling Present removes the 10 heat minutes and relabels the protocol as ice-only until the swelling resolves.
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