How to use this calculator
Straight-line depreciation allocates the difference between purchase and residual value evenly across useful life. Book value is an accounting estimate, not a resale quote. Actual proceeds depend on condition, hours, attachments and demand.
The formula
Annual depreciation = (purchase − residual) / useful life. Book value at year t = purchase − annual depreciation × min(t, useful life). Resale sensitivity varies your assumption by ±20%, capped at purchase price.
What to keep in mind
This is not tax depreciation. MACRS, Section 179, bonus depreciation and jurisdiction-specific rules are excluded.
Use consistent nominal USD values. Taxes default to zero because rates and exemptions vary. Supply applicable sales and property taxes from your jurisdiction. Income tax deductions and credits are excluded. Rental energy and maintenance are assumed included in the entered rental rate; add any renter-paid costs to that rate.