Our wellness calculators are free tools that give you a real number to plan around instead of guessing. Each one focuses on a specific question about thermal therapy or recovery, using commonly referenced guidance rather than a rough estimate, so the numbers you get are genuinely useful for planning a session.
Heat and Cold Calculators
Sauna Session Calculator
Estimates a starting sauna duration and weekly frequency based on your experience level and heat setting. Try the Sauna Session Calculator.
Cold Plunge Duration Calculator
Estimates a safe plunge duration based on your water temperature and cold exposure experience. Try the Cold Plunge Duration Calculator.
Ice Bath Temperature Calculator
Recommends a temperature and duration range based on your goal, muscle recovery, cold tolerance, or mental resilience training. Try the Ice Bath Temperature Calculator.
Recovery and Hydration Calculators
Recovery Heart Rate Calculator
Uses the Karvonen formula to estimate your personal active recovery heart rate zone from your age and resting heart rate. Try the Recovery Heart Rate Calculator.
Sweat Loss Calculator
Estimates fluid lost during a session from your before and after weight, with a rehydration target to match. Try the Sweat Loss Calculator.
How to Use These Calculators Together
Most people get the most value starting with the Sauna Session or Cold Plunge Duration Calculator to set a safe starting point, then checking the Sweat Loss Calculator after a heat session to know how much fluid to replace. If active recovery days are part of your routine, the Recovery Heart Rate Calculator helps confirm you are staying in a genuinely low-intensity zone rather than accidentally training harder than intended.
Who These Calculators Are For
Anyone starting or adjusting a thermal therapy or recovery routine who wants a real number to plan around, rather than a generic rule of thumb that may not fit their experience level or setup. They are equally useful for someone buying their first sauna and someone refining a routine they have followed for years.
Why Real Numbers Beat Rules of Thumb
Generic advice like sit in the sauna for twenty minutes or plunge until you cannot take it anymore ignores your actual experience level and the specific temperature you are working with. A calculator built around your inputs gives a number that is meaningfully closer to right for you, which matters more as you build a consistent, longer-term routine.
These tools are also worth revisiting periodically, not just once. Your tolerance and experience level shift as you build a routine, so checking back in every few weeks keeps your sessions aligned with where you actually are, not where you started.
Every calculation happens instantly in your browser, with no sign-up and nothing stored, so there is no friction to running a quick check before a session.
Explore Related Categories
Put your numbers to use with equipment from Thermal Therapy and Recovery Tech, or read the reasoning behind these practices in Recovery Science.
Frequently Asked Questions
Are these calculators accurate?
They use commonly referenced wellness and recovery guidance, but any calculator is an estimate. They are most useful as a starting point, not an exact clinical measurement, and are not a substitute for medical advice.
Do I need to sign up to use them?
No, every calculator on the site is free and requires no account or sign-up.
Which calculator should I start with?
If you are new to thermal therapy, the Sauna Session or Cold Plunge Duration Calculator gives the most broadly useful starting point.
All calculators are free, instant, and require no sign-up.