fastingfree.Open the timer →

FASTING FREE / TIME TOOLS

Fasting time calculator

Choose a start time and a duration to see when that time ends. Free to use, with no account required.

Choose your times

Time zone: your device’s time zone. Nothing you enter here is saved or uploaded.

Use your device’s local time. You can preview a past or future time.

Your chosen duration

The calculator accepts 1 minute to 168 hours. This range is a tool limit, not a suggested fasting length.

How this calculator works

The result adds your chosen hours and minutes to a start time. It shows the full date and the local time-zone offset, including when the result falls on another day.

When clocks move forward, a skipped local start time is rejected. When clocks move back and a time happens twice, you choose which one you mean. The duration always counts elapsed time.

A preview, with you in control

Calculating a time does not start a timer or create a saved record. You can choose to carry the duration to the timer, review it, and start a session yourself. A planned start time is not carried over.

This tool does not tell you when to eat or how long to fast. It does not measure body changes. Read the safety information before changing your eating routine.

Need help with a running timer? Read the timer guide.