CalcBoard / All Unit Converters / Time

Time Converter

Milliseconds through years — with the calendar assumptions stated up front, because that is where time conversions go wrong.

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Time conversion is exact right up until you reach months and years, and then it stops being a unit conversion at all and becomes a calendar question. This converter is explicit about the assumption it makes: a month is 30 days and a year is 365 days, matching the app.

That is the right answer for “how many hours in a working year” and the wrong answer for “how many days until 14 March”. Real months are 28–31 days and roughly one year in four has 366. For anything that lands on a specific date, count the calendar rather than converting a unit.

Time Converter

1 Hour = 60 Minute
Converted in your browser. Nothing is sent anywhere.

This page’s converter uses ordinary JavaScript numbers, so long results round like any web calculator. CalcBoard’s in-app converter uses exact decimal arithmetic and works with no connection at all.

Common time conversions

Common time conversions for 1, 5 and 100 units
Conversion15100
Hour → Minute603006000
Day → Hour241202400
Week → Day735700
Year (365 days) → Day365182536500
Minute → Second603006000
Month (30 days) → Day301503000

Every time unit CalcBoard converts

All 8 units in this category, with the exact factor each one uses to reach the base unit (second). These are the same constants the app computes with.

Every time unit with its conversion factor and tier
UnitIn secondsTier
Millisecond0.001Premium
Second1Premium
Minute60Premium
Hour3600Premium
Day86400Premium
Week604800Premium
Month (30 days)2592000Premium
Year (365 days)31536000Premium

Convert without a browser

This page needs a connection. The CalcBoard app does the same conversions offline, with exact decimal arithmetic, and puts the converter next to a working calculator — so you can convert a measurement in one panel and immediately use it in a formula in the next, without copying anything by hand.

Free vs. Premium, honestly: the free app includes 2 panels, basic mode, 3 converter categories, and your last 10 history entries — no ads, no time limits. A one-time $2.99 purchase (no subscription) unlocks scientific and programmer modes, up to 8 panels, the shared value tray, all 10 converter categories, full history with search and CSV export, and all themes and button styles.

Frequently Asked Questions

How many hours are in a year?
Using the 365-day year this converter assumes, 8,760 hours. A leap year has 8,784, and the mean tropical year works out to about 8,765.8 hours.
How many days is a month?
This converter uses 30 days, which is a stated convention rather than a fact — actual months run 28 to 31 days. For date arithmetic, use a calendar rather than a unit conversion.
How many seconds are in a day?
86,400 — that is 60 seconds × 60 minutes × 24 hours, and it is exact. Occasional leap seconds are the only exception, and they are not applied here.

Convert offline, in the app

All 79 units, exact decimal maths, alongside a live calculator. Free to download.

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