Free Tool

Cost Segregation Calculator

Add the buildings you own. See how much depreciation a cost segregation study could move into the first year, including a one-time catch-up for buildings you already own.

About 1 minute per building Bonus rules for every year since 2015 No commitment required

Your buildings

Round numbers are fine.

The calculator needs JavaScript to run. Book a Discovery Call and we will estimate the first-year depreciation for your buildings with you.

This tool produces estimates only. The depreciation for each building is set by a cost segregation study. Results do not constitute tax advice.

What You'll Get

First-year depreciation with and without a study, for each building
A one-time catch-up for buildings you already own
The bonus rate that applies to your dates, and why
The 179D deduction alongside it, for buildings you built

Bonus Depreciation by Year

Acquired after Jan 19, 2025 (40% by election for 2025)	100%
In service 2026, acquired earlier	20%
In service 2025, acquired earlier	40%
In service 2024	60%
In service 2023	80%
In service Sept 28, 2017 to 2022	100%
In service 2015 to Sept 27, 2017	50%

For 5, 7 and 15-year property. Rows from 2017 on are for property acquired after Sept 27, 2017; for a building you built, acquired means construction started. Buildings bought from a prior owner before Sept 28, 2017 generally got none.

Already Own the Building?

This calculator covers buildings placed in service from 2015 on. Buildings you already own can still claim the depreciation they missed, as a one-time catch-up in a single year, without amending past returns.

About this calculator

What does this calculator estimate?

It estimates the depreciation you could deduct in the first tax year with a cost segregation study, compared with the standard schedule for the building: 39 years for most commercial property and 27.5 years for residential rentals. A study moves parts of the building into 5, 7 and 15-year property, which can qualify for bonus depreciation.

Can I use it for a building I bought years ago?

Yes, for buildings placed in service from 2015 on. The depreciation missed in earlier years is claimed as a one-time catch-up through an accounting method change, without amending past returns. For a building placed in service before 2015, book a call and we will look at it together.

How does 179D fit with cost segregation?

For a building you built, the 179D deduction is taken first and reduces the building's basis by the same amount. The calculator takes it off the building portion before figuring depreciation, then shows 179D on its own line.

How accurate is the estimate?

It applies the IRS depreciation tables and the bonus depreciation rules for your dates to the typical mix of components for your property type. The range shows how much that mix varies from building to building. A cost segregation study sets the actual figures.