How do you calculate ddb depreciation?

Double declining balance (DDB) depreciation is calculated by first determining the straight-line depreciation rate, which is found by dividing 100% by the asset's useful life. The DDB rate is then doubled. To calculate the depreciation expense for each period, multiply the DDB rate by the asset's book value at the beginning of the period. This process continues until the asset's book value reaches its salvage value.