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BC to AD Year Converter - Free Historical Date Calculator

Accurate BC to AD year converter. Calculate time spans across historical dates with automatic year zero correction. Free tool for historians, students, and genealogists.

BC/AD Year Converter

Input Details

Enter Year

Select Era

How BC/AD Conversion Works

The BC/AD dating system has no year zero. The timeline jumps directly from 1 BC to AD 1.

When calculating time spans across the BC/AD boundary, you must subtract 1 to account for the missing year zero.

Time Calculation Rules:

Years before AD 1: BC year minus 1 (e.g., 100 BC is 99 years before AD 1)
Time span across boundary: BC year + AD year - 1 (e.g., 50 BC to AD 30 = 79 years)

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