Convert days to hours

One day equals 24 hours. To convert any number of days to hours, multiply by 24.

The converter above works in both directions and updates as you type. Below you will find the formula, a worked example and a reference table of common values.

Time conversions are exact down to the day and approximate above it. Seconds, minutes, hours and days have fixed ratios, but a month has no fixed length and a year has two — 365 days in the calendar and 365.25 in the astronomical convention used here. For anything with legal or contractual weight, count the actual calendar dates rather than converting a duration, because the difference accumulates precisely where it is least welcome.

days to hours formula

To go the other way, use day = hour ÷ 24.

About these units

A day is exactly 86,400 seconds by convention, though the Earth’s actual rotation drifts slightly against it — the discrepancy leap seconds were introduced to absorb.

The hour is 3,600 seconds. Its length is arbitrary in physical terms: it descends from dividing daylight into twelve parts, which meant the hour changed with the seasons until mechanical clocks fixed it.

Day is also written days. Hour is also written hours, hr and hrs.

Sources

1. Bureau International des Poids et Mesures, The International System of Units (SI), 9th edition, 2019.