# How Lyfta calculates calories

> Lyfta estimates calories from the workout timer, your body weight, your gender, and stored volume. It does not use heart rate.

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**URL:** https://support.lyfta.app/en/article/how-lyfta-calculates-calories
**Category:** Using Lyfta
**Subtopic:** Features
**Last updated:** 2026-09-28
**Platforms:** ios, android

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Lyfta estimates calories for a finished workout. It does not read heart rate, and it does not copy the number from Apple Health, Health Connect, or a watch.

The estimate is saved when you finish the workout. Edit the workout and save it to calculate the number again. Changing your profile later does not change calories on a workout that is already saved.

## What the estimate uses

- The workout timer. Rest between sets is included. Time the workout was paused is not.
- Body weight on your profile, converted to kilograms.
- Gender on your profile.
- Total volume stored on the workout, when that volume is already there.

## How the number is calculated

Effort starts at 3 METs. Each kilogram of volume per minute adds 0.009, and effort never goes above 6 METs.

Calories are that effort, times your body weight in kilograms, times the hours on the timer. A profile set to female is counted at 95%. Any other profile, including one with no gender, is not reduced. Lyfta drops the fraction and keeps the whole number.

If body weight is missing, or it is 20 or below in the unit on your profile, Lyfta uses 60 kg (132 lb) for a female profile and 72 kg (158 lb) otherwise.

A workout you just finished does not include set volume in that first estimate, so effort stays at 3 METs. Duration and body weight still change the number. Volume raises the estimate when you edit and save a workout that already has a stored total volume.

## If the number looks wrong

A longer timer raises calories even while you rest between sets. Two workouts of the same length and body weight can show the same calories when neither one included stored volume.

Apple Health, Health Connect, and a watch use their own estimates. See [Connect Lyfta to Apple Health](/article/connect-apple-health) or [Connect Lyfta to Health Connect](/article/connect-health-connect).

> **Still looks wrong?** Email support@lyfta.app with the date, the timer, your body weight and unit, and the calorie number Lyfta showed.

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## Related articles

- [How to log a workout](https://support.lyfta.app/en/article/logging-workouts)
- [Connect Lyfta to Apple Health](https://support.lyfta.app/en/article/connect-apple-health)
- [Connect Lyfta to Health Connect](https://support.lyfta.app/en/article/connect-health-connect)

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