Understanding eating windows
Learn how clock times are calculated and what an eating-window result means.
This guide does not provide medical advice. Speak with a healthcare professional before changing your routine if you have a health condition, take medication, are pregnant or breastfeeding, are under 18, or have a history of disordered eating.
An eating window is a span between a first meal time and a closing time. If you enter noon and eight hours, the calculator displays noon to 8 p.m. The rest of the 24-hour cycle is 16 hours. That arithmetic does not tell you whether the routine is suitable for you.
Crossing midnight
A late first meal can place the closing time on the next calendar day. For example, 7 p.m. plus eight hours is 3 a.m. the next day. The calculator labels that rollover.
Choosing a routine
People’s work, sleep, family meals, and medical needs differ. This site offers time calculations, not an individualized eating plan. Research on time-restricted eating is ongoing, including questions about longer-term outcomes. The National Institute on Aging overview explains the state of the research and advises discussing significant changes with a healthcare provider.
Further reading
National Institute on Aging: fasting diets overview
NIDDK: intermittent fasting and diabetes