Your intermittent fasting window, calculated. Enter when the fast started and your plan — see exactly when to eat. No signup, no fluff, everything stays in your browser.

Your eating window

The window always closes where the fast began — one number to remember, one clock to watch.

–is when your window opens

Fasting depletes more than willpower

Long fasts flush sodium, potassium, and magnesium — the tired, headachy part of fasting is usually electrolytes, not hunger. Plain water isn't the full answer.

Fasting-friendly electrolytes → Coffee & tea for the fast hours →

Compressed window, same protein target

Hitting your daily protein in an 8-hour window is the hard part — SuppCalc's protein calculator does that math.

What ratio do you already live?

Skipped breakfast without calling it anything? Find your plan. Last bite yesterday, first bite today.

–hours fasted
Not medical advice. Diabetes, pregnancy, a history of eating disorders, or medications that require food all change the math — fasting isn't right for everyone, and a doctor is the right calculator for those cases.