Miscellaneous Utilities

Roman Calendar Converter

The Romans didn't number days sequentially. Instead, they counted backward from three named reference points in each month: the Kalends (1st), Nones (5th or 7th), and Ides (13th or 15th). Convert any Gregorian date to its proper Roman expression.

Enter a Date

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Gregorian Date

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Reference Point

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Days Before (Roman count)

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Roman Month Name

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Month	Kalends	Nones	Ides
March, May, July, October	1st	7th	15th
All other months	1st	5th	13th

How Romans Counted Days

Romans counted days inclusively and counted backward to the next reference point. If a day was 3 days before the Ides (counting the Ides itself), they said "three days before the Ides" — written ante diem III Idus (a.d. III Id.).

On the reference day itself: Idibus (ablative) — "on the Ides." The day before: pridie — "the day before."

Julius Caesar was assassinated on the Ides of March — Idibus Martiis — March 15, 44 BC. The phrase "Beware the Ides of March" comes from Shakespeare's Julius Caesar.