How do I calculate when my fast ends?

Add your target hours to your start time — this calculator does it instantly, including crossing midnight.

What if I want to extend my fast?

You can extend, but decide before hunger peaks — and never extend past what feels safe.

When Will My Fast End?

The question every faster asks at hour 6. Enter your start time and target — get the exact end date and time, plus what to expect along the way.

I started fasting at

Target length

Your fast ends —

What happens between now and then: hours 0–4 run on your last meal; 4–8 taper off; 8–12 is the switchover to stored fuel (often the hungriest stretch — it usually passes in ~20 minutes); 12–16 is the steady cruise most daily fasters live in.

Ending early is fine. The plan was a guess; your body is data. Fluent Fast never shames an early finish and never nudges you to extend.

Track it live instead

Fluent Fast's timer counts up in real time, shows what's happening each hour, and celebrates when your window opens. Free forever.

Open the free timer →

More calculators: 18:6 · 20:4 · OMAD · 36-hour · Start time · How long?

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