Workout calculator · Free

Workout Sweat Rate Calculator

Record a workout’s before-and-after weight, drinks and duration to estimate how much you sweated in those conditions.

Use the calculator No sign-up · Instant estimates

Interactive tool

Measure your workout

Replace the sample session with yours.

Weight before(kg)

Weight after(kg)

Fluid consumed(ml)

Urine passed during session(ml)

Workout duration(minutes)

Weigh on the same scale in similar dry clothing. Log only the fluids consumed between your two weigh-ins.

Results update as you change the inputs.

Estimated session sweat rate

1 L/hour

Estimated total

1 L

Session length

60 min

Session estimate only. This is not an hourly drinking target.

How the estimate works

Estimated sweat loss (litres) = weight before (kg) − weight after (kg) + drinks (litres) − urine (litres). Divide by workout hours for litres per hour.

Use the same scale, similar minimal dry clothing, and towel off before the second reading. Record fluids consumed between the two weigh-ins. Repeat on separate days: weather, effort and clothing change the result.

This measures a session; it does not prescribe how much to drink. Do not force fluids to match the result. Drinking too much can be harmful. Get individual advice for prolonged events or medical fluid restrictions.

National Athletic Trainers’ Association: fluid replacement position statement

Method reviewed against the linked source · 30 September 2026