Home Office Calculator
Calculate your home office tax deduction and estimate setup and running costs
Office Space
Monthly Expenses
Setup Costs (one-time)
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Quick summary
This calculator determines your home office percentage (office area ÷ total home area), then computes the deductible portion of your rent/mortgage, utilities, and 50% of your internet costs. The estimated tax savings assume a 25% effective tax rate. This is for estimation only — consult a tax professional.
Reviewed by Simple Calculators TeamLast reviewed
How to use this calculator
- Enter the inputs requested by the calculator.
- Choose the units or options that match your situation and review the assumptions.
- Run or update the calculation to see the result.
- Review the result, breakdown, and formulas shown on the page.
- Check the inputs, units, dates, and limitations before saving or sharing the result.
Home Office Deduction Formulas
Office Percentage
- Office Area
- Square footage of dedicated home office space
- Total Home Area
- Total square footage of your home
Worked example
150 sq ft office in 1,200 sq ft home
- Given
- Office = 150 sq ftHome = 1,200 sq ft
- Calculation
- Result
- 12.5% deductible
Annual Deduction
- Deductible Rent
- Monthly rent × office percentage
- Internet
- 50% of monthly internet cost (standard IRS rule)
Worked example
$2,000 rent, 12.5% office, $80 internet
- Given
- Rent = $2,000Office % = 12.5%Internet = $80
- Calculation
- Result
- $3,480 annual deduction
Frequently asked questions
What qualifies as a home office deduction?
The space must be used regularly and exclusively for business. It must be your principal place of business or where you meet clients. W-2 employees generally cannot claim this deduction; self-employed individuals can.
What is the simplified method vs. regular method?
The simplified method allows $5 per sq ft (up to 300 sq ft = $1,500 max). The regular method (this calculator) allows the actual percentage of home expenses and is usually larger for higher rent.
Can I deduct my internet for home office?
Yes, 50% of your internet is deductible if you work from home, even if you use it for personal use too. If internet is exclusively for business, 100% is deductible.
Key terms
- Exclusive Use
- IRS requirement that the home office space be used only for business, not mixed personal use.
- Home Office Percentage
- The ratio of office area to total home area — determines what fraction of home expenses is deductible.
- Simplified Method
- An IRS alternative that allows $5/sq ft deduction (max 300 sq ft) instead of tracking actual expenses.
Methodology, sources & limitations
This page shows the formula, assumptions, and limitations used for this estimate. Rates, thresholds, and other time-sensitive inputs can change, so verify them against the relevant official source before relying on a result.
For our review approach and the primary sources we consult, see the methodology and source policy. If you spot an outdated figure or formula, please contact us with a correction.