Depreciation Formulas Reference

A quick reference guide for all major depreciation calculation methods.

Straight Line (SL)

(Cost - Salvage) / Useful Life

The standard method. Allocates cost evenly over the life of the asset.

Double Declining Balance (DDB)

Book Value × (2 / Useful Life)

Accelerated method. Takes 200% of the straight line rate against the current book value.

Sum of Years Digits (SYD)

(Cost - Salvage) × (Remaining Life / SYD)

SYD Factor: n(n+1)/2
where n = useful life.

Units of Production

(Cost - Salvage) × (Units Produced / Total Estimated Units)

Variable method based on actual usage (miles, hours, units).

Common Formulas