BC to AD Calculator
Calculate time differences between BC/BCE and AD/CE dates with historical accuracy
BC/AD Date Calculator
BC = Before Christ, AD = Anno Domini
Before Christ
Anno Domini (Year of our Lord)
Historical Timeline Examples
Founding of Rome to present day
2,776 yearsQin Dynasty unification to American Independence
1,996 yearsJulius Caesar assassination to Norman Conquest
1,109 yearsBronze Age collapse to Fall of Constantinople
2,652 yearsNotation Guide
BC/AD System
BC: Before Christ
AD: Anno Domini (Year of our Lord)
Traditional Christian dating system
BCE/CE System
BCE: Before Common Era
CE: Common Era
Modern secular alternative
Key Facts
There is no year zero in the BC/AD system
1 BC is immediately followed by 1 AD
BCE/CE uses the same numbering as BC/AD
The reference point is the same for both systems
Understanding BC/AD and BCE/CE Dating
What Do These Abbreviations Mean?
The BC/AD system was developed in medieval Europe to track time using the birth of Christ as a reference point. Later, the BCE/CE system was introduced as a secular alternative that maintains the same timeline but removes religious connotations.
Why Subtract One?
- •There is no year zero in the BC/AD timeline
- •The year 1 BC is immediately followed by 1 AD
- •This creates a one-year difference in calculations
Calculation Formula
Time Between BC and AD
Years = BC Year + AD Year - 1
Years Ago
Years = BC Year + Current Year - 1
Example: From 100 BC to 50 AD = 100 + 50 - 1 = 149 years