Yes — keep contemporaneous records (mileage log, receipts for $75+, calendars for meals). The IRS disallows undocumented deductions on audit.

Simplified vs actual home office?

Simplified is $5/sqft up to 300 sqft ($1,500 max). Actual method usually wins for higher rent/mortgage; this tool models the actual method.

Can I deduct my whole phone?

Only the business-use portion. The IRS expects you to substantiate the percentage.

Business Deduction Estimator

Tally the deductions self-employed people miss most, then estimate the tax savings at your marginal rate.

Business deduction estimator

Home sq ft

Office sq ft

Annual home costs (rent/mortgage interest, utilities)

Business miles driven

Meals (client/biz, 50%)

Software & subscriptions

Equipment (Sec 179 eligible)

Phone/internet annual

Phone/internet % business

SE health insurance

Retirement contributions (SEP/Solo 401k)

Marginal tax rate %

How it works

Home office = annual home costs × (office sqft / home sqft).
Mileage at the 2025 standard rate of 70¢ per business mile.
Meals limited to 50%; phone/internet pro-rated by business use %.
Section 179 equipment, SE health insurance, and retirement contributions added directly.

Assumptions

Estimate only — doesn't validate documentation, exclusive-use, or SSTB rules.
Marginal rate applied flat to total deductions for the savings figure.
Doesn't include depreciation on assets beyond Section 179.

Frequently asked questions

Related calculators

These calculators provide estimates for general planning only and are not tax, legal, or financial advice. Always verify with a licensed CPA for your specific situation.