How to Convert Decades to Hours To convert decades to hours, multiply the number of decades by 87,658.2 (the number of hours in one decade). This calculation accounts for: 1 decade = 10 years 1 year = 365.242 days (accounting for leap years) 1 day = 24 hours Conversion Formula: Hours = Decades × 87,658.2 Common Conversions 1 decade = 87,658.2 hours 2 decades = 175,316.4 hours 5 decades = 438,291 hours