Declining-Balance Depreciation Calculator
Compute double-declining or declining-balance depreciation and book value by year, matching the Excel and Google Sheets DDB function.
Numbers stay in your browser. The default is a cost of 10,000, salvage of 1,000, a 5-year life, and double-declining balance, which is 4,000 in year 1. This is not tax advice.
Quick answer: with cost in B2, salvage in C2, life in D2, and the year in E2:
=DDB(B2,C2,D2,E2)Leave the factor off to use 2 (double-declining), or pass a fifth argument for another rate, as in =DDB(B2,C2,D2,E2,1.5).
10,000 cost, 1,000 salvage, 5 years, factor 2
The declining rate is 2 ÷ 5 = 40% of the current book value. Year 1 is 10,000 × 0.4 = 4000, leaving a book value of 6000. Year 2 is 6,000 × 0.4 = 2400. In Google Sheets on 12 November 2026, =DDB(10000,1000,5,1) returned 4000, the book after year 1 was 6000, and =DDB(10000,1000,5,2) returned 2400.
Year 5 is the salvage cap at work. After year 4 the book value is 1,296, and 40% of that would be 518.4, but only 296 can be taken without going below the 1,000 salvage. =DDB(10000,1000,5,5) returned 296. Straight-line on the same inputs, by contrast, is 1,800 every year; see the straight-line calculator.
Factor, and what this does not do
Factor 2 is double-declining. A 150% declining balance uses 1.5. Some systems switch to straight-line in a later year when that method would depreciate more; DDB does not make that switch by itself — it only floors at salvage. Mid-year conventions and tax tables can also change year 1. This calculator follows the DDB arithmetic only.
Questions that come up
What is the declining-balance formula in Excel or Google Sheets?
Use =DDB(cost, salvage, life, period). The optional fifth argument is the factor; if you omit it, DDB uses 2, which is double-declining balance. For a cost of 10,000, salvage of 1,000, and a 5-year life, year 1 is 4,000 and year 2 is 2,400.
Why is the last year smaller than the declining rate suggests?
DDB will not take book value below salvage. In the test workbook, year 5 would have been 0.4 × 1,296 = 518.4, but only 296 was left above the 1,000 salvage, so DDB(10000,1000,5,5) returned 296.
How is this different from straight-line depreciation?
Straight-line charges the same amount each year: SLN(10000,1000,5) is 1,800 every year. Declining-balance charges more up front (4,000 in year 1 here) and less later. Use the method your books actually require; this page is not tax advice.