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Intermittent Fasting Calculator

Plan fasting versus eating hours in a 24-hour model.

Use the calculator below, then review the formula, a numeric example, and the reference table to understand how the intermittent fasting window result is produced.

Educational tool only. It does not replace advice from a licensed clinician, dietitian, or exercise physiologist.

Calculator inputs

Result

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What is this calculator?

Plan fasting versus eating hours in a 24-hour model. The formula, a worked example, and a reference table are below. Results are for education only, not medical advice.

How it works

In a 24 h model: fasting hours = 24 − eating window hours.

Example

8 h eating window 16 h fasting in the simple model.

Reference Table

ValueMeaning
16:8Fast 16, eat 8
12:12Gentler entry
OMADOne meal–advanced, not for everyone

FAQ

Medications with food?

Some require meals; fasting may be unsafe.

Disordered eating history?

Avoid rigid fasting without specialist support.

Athletes?

Training fueling windows need customization.

Better fat loss?

Adherence drives results; total calories still matter.