Ramadan Fasting Hours Calculator

Work out ramadan fasting hours instantly with clear inputs, formula shown and shareable results.

About Ramadan Fasting Hours Calculator

The fast runs from Fajr to Maghrib, so its length is the difference between those two times wrapped into a 24 hour day, and the eating window is the remainder. Fast length varies enormously with latitude and season, from about eleven hours near the equator to over twenty in far northern summers.

Formula

Fast length

hours = Maghrib time - Fajr time, wrapped into 24 hours

Worked example

With the default values below, Ramadan Fasting Hours Calculator returns Length of the fast of 15.200. Change any input above and every figure here is recalculated in your browser.

Inputs used

Fajr time as a decimal houraccepts 0–23.99: 4.2
Maghrib time as a decimal houraccepts 0–23.99: 19.4

Results

Length of the fast: 15.200 h
Fast in hours and minutes: 15h 12m
Eating window: 8.800 h
Total fasting hours over thirty days: 456.0 h

Step by step

1Values used
2Fast length
3Length of the fast= 15.200 h
4Fast in hours and minutes= 15h 12m
5Eating window= 8.800 h
6Total fasting hours over thirty days= 456.0 h

Assumptions and limits

The result is derived only from the 2 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is the Ramadan Fasting Hours figure worked out?

hours = Maghrib time - Fajr time, wrapped into 24 hours. The fast runs from Fajr to Maghrib, so its length is the difference between those two times wrapped into a 24 hour day, and the eating window is the remainder.

Why does this matter?

Fast length varies enormously with latitude and season, from about eleven hours near the equator to over twenty in far northern summers.

What do I need to enter?

Enter fajr time as a decimal hour, maghrib time as a decimal hour. The defaults shown are a realistic worked example — swap in your own figures to get a result you can use.