BC/AD Timeline Calculator
Calculate years between historical dates
BC (BCE)
AD (CE)
BC (BCE)
AD (CE)
How to Calculate Time Between BC and AD
Calculating time across history requires accounting for a specific mathematical quirk: There is no "Year 0" in the Gregorian or Julian calendars. The timeline jumps directly from 1 BC (Before Christ) to 1 AD (Anno Domini).
The Calculation Logic
- Same Era: If both dates are in the same era (both BC or both AD), simply subtract the smaller number from the larger number.
- Across Eras: If one date is BC and the other is AD, add the years together and subtract 1.
Historical Examples
| Event A | Event B | Total Years |
|---|---|---|
| Pyramid of Giza (2560 BC) | Today (2024 AD) | 4,583 Years |
| Julius Caesar Dies (44 BC) | Fall of Rome (476 AD) | 519 Years |
| 1 BC | 1 AD | 1 Year |