Calculate how many years between BCE (BC) and CE (AD)

Happy anniversary 

It being the Ides of March, I was searching for a simple tool to calculate the number of years between the assassination of J Ceasar and now. Unfortunately the only online calculators I could find only worked in the CE date range, so I built a simple(-ish) spreadsheet to calculate between any two years BCE and CE.*

I hope this might be of use to someone, because from some brief Googling there are a lot of people out there with a very poor grasp on both timelines and number lines.

With the complexities introduced by the change between Julian and Gregorian calendars, I've stuck with year integers only.

How to use

Go to the editable online calculator spreadsheet.

Put your start and end years in (numbers only) and select BCE or CE from the drop down box below each.

Live calculator view


  • I've put in very little data validation so this will break easily!
  • Don't use negatives to represent BCE, use the dropdown
  • There is no year zero in our calendar, so if you use 0 you'll get an incorrect output
  • Make sure the start year is prior to the end year
  • These are whole years only, i.e. 15 March - 15 March, if you have a partial year please adjust your answer manually

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