b2KIT

Property Depreciation Calculator

Calculate residential and commercial property depreciation using straight-line and MACRS with cost segregation analysis.

Tested tool guide Tested browser tools Checked August 16, 2026

What Property Depreciation Calculator does, with a checked example

This tool turns a purchase price into a year-by-year depreciation schedule under the IRS recovery rules: straight-line over 27.5 years for residential rentals and 39 years for commercial buildings, with the mid-month convention, plus the accelerated MACRS tables for components carved out by cost segregation. It is a calculator, not a tax opinion - the output is only as valid as two inputs: the land value you exclude (land never depreciates) and the placed-in-service date. The surprise is that depreciation is recaptured at sale, so it accelerates deductions rather than eliminating them.

Worked example

A concrete input and expected output from the current implementation.

Input

Commercial purchase $1,000,000, land $150,000. Cost segregation: $100,000 to 5-year personal property (200% declining balance), $50,000 to 15-year land improvements (150% declining balance), remainder to the 39-year building. Placed in service in January.

Expected output

Year 1 depreciation: building $17,200.85 (11.5/12 of the $17,948.72 annual straight-line amount), 5-year property $20,000.00 (20% of $100,000), land improvements $2,500.00 (5% of $50,000). Total: $39,700.85. Without segregation the $850,000 building alone would produce $20,886.75, so the allocation front-loads $18,814.10 of extra deduction in year 1.

Each class follows its own IRS schedule: the mid-month convention gives the 39-year building 11.5 months of depreciation in its first year, while 5-year property opens at 20% and 15-year property at 5% under the half-year convention. The three schedules sum to the year-1 total.

How the result is produced

1

Straight-line and the mid-month convention

Buildings depreciate straight-line: depreciable basis (purchase price minus land) divided by 27.5 years for residential rentals or 39 years for commercial property. The mid-month convention treats the property as placed in service at the midpoint of its month, so the first and last years get a half month plus whole months, never a full year. The day of the month you close does not change the schedule.

2

Cost segregation allocation

The tool runs a separate schedule for each component class: 5-year personal property at 200% declining balance, 15-year land improvements at 150% declining balance, and the building on straight-line. Under the half-year convention the first-year rates are 20% and 5%. Total deductions over all lives are capped at the depreciable basis, so segregation front-loads deductions rather than creating new ones - useful only if the deduction is worth more to you now than later.

Good uses

  • Estimating first-year and lifetime deductions before making an offer on a rental or commercial building, to compare properties or to see what a purchase price really costs after tax.
  • Deciding whether to commission a cost segregation study by comparing the accelerated schedule against the plain straight-line building deduction.
  • Building a depreciation and remaining-basis schedule to hand to a tax preparer or to forecast rental taxable income over the holding period.

Limits and checks

  • Land is never depreciable, but the tool needs a land value as input; if you leave land in the basis, every year's deduction is overstated. Sales contracts often do not separate land from building, and choosing a defensible split is your job, not the tool's.
  • The schedule assumes the property is in service from the start of the year. A placed-in-service date later than acquisition, months the unit sat vacant before its first rental, or any personal use of the property reduce the amount you may actually deduct.
  • A cost segregation result is only as strong as its allocation; aggressive reclassification of building costs into 5-year property has been challenged on audit. The tool also does not model bonus depreciation or Section 179, separate elections that can change the first year substantially.

Common questions

Can I depreciate my primary residence with this tool?

No. Depreciation applies only to property held for business or rental use, so a primary residence is not depreciable. If part of a home is rented - a room or a basement unit - only the basis allocable to the rental portion qualifies, and you would enter that reduced basis, not the full purchase price.

Do I pay the depreciation back when I sell?

Yes, effectively. Deductions reduce your basis, so more gain is taxable at sale. For the real estate itself, prior depreciation is recaptured as unrecaptured Section 1250 gain taxed at up to 25%; the personal-property components from a cost segregation study recapture at ordinary income rates. This tool shows deductions, not sale-year tax.

References and verification

The example and behavioral notes were checked against the browser implementation. Standards and primary references below define the relevant format, formula, or platform behavior.

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