This depreciation calculator estimates annual depreciation for an asset. Enter cost, salvage value, useful life in years, and choose straight line or double declining. The main result is annual depreciation for planning and teaching examples.
Bookkeepers and small business owners use it to sketch schedules before accounting software posts entries. Tax rules can differ from book methods.
Straight line method
Example with defaults: cost $50,000, salvage $5,000, life 5 years. Depreciable basis is $45,000. Annual straight line depreciation is $9,000.
Double declining year 1
Same $50,000 asset over 5 years: year 1 declining depreciation = 50,000 × (2 ÷ 5) = $20,000. Later years need a continuing book value schedule. This tool highlights the year 1 declining amount in that mode.
| Method | Annual amount (example) |
|---|---|
| Straight line | $9,000 |
| Double declining year 1 | $20,000 |
How to use the fields
- Cost is what you paid to place the asset in service, following your book policy.
- Salvage is expected value at the end of useful life for straight line basis.
- Years is useful life for the schedule you are modeling.
- Pick the method that matches your example.
Book value idea
After one straight line year, book value is cost minus $9,000 in the example above. After several years, stop at salvage for straight line.
Accounting versus tax
Tax systems may require different lives, conventions, or bonus rules. This calculator is a book style teaching model. Confirm filings with a tax professional.
Related finance screens include the ROI calculator, break even calculator, and profit margin calculator.
Common mistakes
- Using tax bonus percentages inside this simple annual model
- Forgetting salvage in straight line
- Applying declining rate to cost every year without reducing book value
Partial years
Assets placed in service mid year may use conventions that differ from a clean full year. This tool shows full year style amounts for teaching examples.
Choosing useful life
Match life to how long you expect the asset to serve, or to the book policy your accountant sets. Tax lives can differ.
Records
Keep purchase date, cost basis, salvage policy, and method in one place so next year schedule work is consistent.
Practical planning tips
Write down the inputs you used so you can repeat the estimate later. Small changes in rate, depth, hours, or price can move the result more than people expect.
When you compare two options, change one variable at a time. That keeps the comparison honest and easy to explain to a partner, client, or lender.
Units and rounding
Keep units consistent across every field. Mixing inches with feet, litres with gallons, or monthly figures with annual figures is the most common source of wrong answers.
Round only at the end for ordering or payments. Early rounding in each step can stack into a surprising gap versus the live calculator.
What this estimate does not include
Taxes, delivery fees, labor, penalties, and one time service charges are often outside the core formula. Add those on paper when you build a real budget.
Local rules, code requirements, and lender overlays can still change the final decision even when the math is correct.
How to double check the result
Recalculate once with a pencil using the same formula shown on this page. If your manual result is close to the tool, your inputs are probably consistent.
If the two answers diverge, check the field labels again before you trust either number for spending or filing.
When to get a second opinion
Large purchases, structural work, medical or legal questions, and loan contracts deserve a qualified human review. Use this page to prepare better questions, not to replace that review.
Save a screenshot or note of the inputs and result date. That record helps when you talk with a contractor, accountant, or lender later.