Write-off tax savings calculator for freelancers
A $1,000 write-off at 27% only costs you about $730 out of pocket.
A business write-off does not make an expense free — it makes the taxman pay part of it. The government covers your marginal rate of every legitimate business cost.
Enter your expected write-offs and your rates, and this calculator shows what you save and what each business dollar really costs you.
The core idea: write-offs are shared expenses
A business write-off does not make an expense free — it makes the government pay for part of it. When you deduct a business cost, you reduce your taxable income by that amount, and you save tax at your marginal rate on the difference. At a 22% federal rate plus a 5% state rate, a $1,000 business expense only costs you about $730 out of pocket; the other $270 is borne by the tax you no longer owe.
This calculator turns your expected annual write-offs into the dollars of tax they save, and the true out-of-pocket cost of spending on your business. It is the aggregate view that sits on top of the specific deductions the home-office and mileage calculators work out.
Why the rate is what matters
The saving is your expense times your combined marginal rate — federal plus state, at the bracket the deduction lands in. A freelancer in a high-tax state saves more per dollar spent than one in a zero-income-tax state, because both layers of tax are reduced. The calculator adds the two rates, which is why entering your state rate changes the number even though the federal maths is the same.
One subtlety: a deduction reduces taxable income, not the tax bill directly, and it interacts with self-employment tax too. The business expenses that cut your Schedule C profit also cut the base for SE tax. The calculator shows the income-tax side; the SE-tax saving is a bonus on top for most freelancers, which is why the real benefit is often a touch larger than the income-tax figure alone.
What actually counts as a write-off
To deduct a cost, it must be ordinary (common in your field) and necessary (helps your business), and you must keep a record. The usual freelancer suspects: a portion of home internet and phone, software subscriptions, business insurance, professional development, bank and payment fees, mileage and a home-office share, and equipment. The trap is mixing personal and business on the same receipt — the personal part is not deductible, and claiming it is the fast lane to an audit adjustment.
The QBI deduction is a different animal: it is 20% of your profit taken after these expenses have already reduced it, so the write-offs and the QBI break stack rather than overlap.
Using the number
The "true cost of each $1 spent" line is the one to internalise. When a $200 software tool only costs you $146 after tax, the decision to buy it gets easier — and that is the point. Write-offs are not a reason to spend, but they are a reason not to fear the legitimate spending that makes you more productive. The danger is the mirror image: deducting things you would not have bought anyway just to lower a tax bill usually leaves you with less money, because you still paid most of the cost.
An estimate for planning, not tax advice. The calculator uses your marginal rates and ignores phase-outs, the SE-tax interaction, and itemizing limits. Actual savings depend on your full return. Verify against irs.gov and see the disclaimer.
Frequently asked questions
How much do my business write-offs save me in tax?
Roughly your total write-offs times your combined marginal rate (federal plus state, at the bracket the deduction lands in). At 22% federal and 5% state, $12,000 of write-offs saves about $3,240 — so the real out-of-pocket cost is about $8,760. The calculator does this for whatever rates you enter.
Does a write-off make an expense free?
No — it makes the government pay part of it. A deduction reduces your taxable income, and you save tax at your marginal rate on that reduction. At a 27% combined rate, a $1,000 business cost costs you about $730 out of pocket. The tax break covers the rest, not all of it.
Do state and federal write-offs stack?
Yes. A deduction reduces federally taxable income and, in most states, state taxable income too, so you save at both rates. That is why entering your state rate increases the total saving even though the federal maths is unchanged.
What expenses actually count as business write-offs?
Costs that are ordinary (common in your field) and necessary (help your business), with a record kept: a share of home internet and phone, software, business insurance, professional development, bank and payment fees, mileage, a home-office share, and equipment. Personal portions of mixed receipts are not deductible.
Do write-offs also reduce my self-employment tax?
Often, yes. Business expenses that lower your Schedule C profit also lower the base for self-employment tax, so the income-tax saving the calculator shows is usually a slight underestimate of the total benefit for a sole proprietor.
Should I spend more just to get the deduction?
No. A deduction only returns your marginal rate of what you spend, so you still pay most of the cost. Buy what genuinely helps the business; the tax saving is a discount on that, not a reason to spend money you would not otherwise. Claiming things you would not have bought usually leaves you worse off.