Rex says
Money math without the spreadsheet headache. Plug in your numbers and I'll show you exactly where the dollars land.
Try a scenario
Click to load — tweak from there.Inputs
Result
Larger deduction
$2,333
Simplified method
$750
Actual expense method
$2,333
Estimated tax saved
$560
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How to use this
- 1Enter office square feet.
- 2Enter total home square feet.
- 3Enter annual home expenses ($).
- 4Enter marginal tax rate (%).
- 5Read your larger deduction on the right — it updates as you type.
- 6Hit Share to keep the scenario or send it to someone.
About this calculator
The IRS allows a simplified $5-per-square-foot method or an actual-expense method based on the share of your home used for work. This compares both. Educational only — not tax advice.
Worked example
Using the values the calculator loads with:
Inputs
- Office square feet: 150
- Total home square feet: 1800
- Annual home expenses: 28000 $
- Marginal tax rate: 24 %
Results
- Larger deduction: $2,333
- Simplified method: $750
- Actual expense method: $2,333
- Estimated tax saved: $560
What each field means
Inputs
- Office square feet
- The office square feet used in the calculation. Starts at 150 so you have a working example on load. Accepted range: 10–600.
- Total home square feet
- The total home square feet used in the calculation. Starts at 1800 so you have a working example on load.
- Annual home expenses ($)
- The annual home expenses used in the calculation, measured in $. Starts at 28000 $ so you have a working example on load.
- Marginal tax rate (%)
- The marginal tax rate used in the calculation, measured in %. Starts at 24 % so you have a working example on load. Accepted range: 0–50 %.
Results
- Larger deduction
- Returned as a money amount in US dollars and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Simplified method
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Actual expense method
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Estimated tax saved
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
How does the home office deduction estimator work?
The IRS allows a simplified $5-per-square-foot method or an actual-expense method based on the share of your home used for work. This compares both. Educational only — not tax advice. The underlying maths is: Simplified = min(sqft, 300) × $5. Actual = home expenses × office share.
What do I need to enter?
4 values: office square feet, total home square feet, annual home expenses, and marginal tax rate. Each field starts with a sensible default, so you can change one number at a time and watch the result move.
What does the larger deduction result mean?
It is returned as a money amount in US dollars and updates live as you edit the inputs, so you can compare two or three versions of a scenario in a few seconds.
Is this calculator free, and do I need an account?
Yes, it's free, and no account is required. Nothing you type is stored on our servers — the maths runs entirely in your browser.
How accurate is the result?
It applies the standard formula exactly, so the arithmetic is precise. Results are estimates before tax, fees, and inflation unless an input explicitly covers them.
Who is this tool for?
It's built for anyone comparing money scenarios before committing — budgeting a payment, sanity-checking a quote, or seeing what a change in rate or term actually costs.
Accuracy and limitations
- Results are estimates before tax, fees, and inflation unless an input explicitly covers them.
- Rates are treated as fixed for the whole period — variable-rate products will drift from this projection.
- This is educational maths, not financial advice. Check anything contractual with the lender or your accountant.
Related tools
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Home Office Deduction Estimator. Retrieved from https://www.revenuelab.fyi/toolbox/home-office-deduction-estimate
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/home-office-deduction-estimate" target="_blank" rel="noopener">Home Office Deduction Estimator — RevenueLab</a> (2026).</p>
Source: [Home Office Deduction Estimator — RevenueLab](https://www.revenuelab.fyi/toolbox/home-office-deduction-estimate) (2026).