How to Use the Fasting End Time Calculator
Select your fasting start date, start time, and target duration. You'll instantly see when your fast ends, how much time has elapsed, how much time remains, and your progress percentage. Supports all common intermittent fasting protocols from 12:12 to 48-hour fasts.
Common Fasting Protocols
- 16:8 — 16-hour fast, 8-hour eating window (most popular IF method)
- 18:6 — 18-hour fast, 6-hour window (enhanced fat burning)
- 24h / OMAD — one meal a day, done 1–2 times per week
- 48h — extended fast; consult a doctor before attempting
Fasting Safety Tips
Black coffee, plain tea, and water are allowed during most fasts. Stop immediately if you experience severe dizziness, chest pain, or irregular heartbeat. Consult your doctor before fasting if you have diabetes, are pregnant, or have a history of eating disorders.
Frequently Asked Questions
Black coffee (no sugar, no cream), plain herbal tea, and water are generally considered "fasting-safe." Anything with calories — including milk, juice, or bulletproof coffee — technically breaks the fast.
Change the start date to yesterday and enter your actual start time. The calculator will correctly compute elapsed time and the end time.
Start with 12–14 hours (much of which can be overnight sleep). Once comfortable, work up to 16 hours. Don't push to extreme lengths right away.