How much tax do I pay after write-offs?
Tax is figured on profit, not on everything you earned. Enter what came in, then your business costs and miles. See your federal tax after write-offs, and how much those write-offs saved you. 2026 rates.
2026 federal rates, standard deduction, no credits or QBI deduction, no state tax. Miles are split evenly across the year's two mileage rates. Only the business share of a cost counts: if your phone is half for work, enter half the bill.
Worked example: $40,000 earned, $6,028 of write-offs
Jasmine does lashes and nails out of a shared studio. She brought in $40,000 this year. She spent $3,800 on supplies, her phone, booking apps and other costs, and drove 3,000 business miles.
- What she earned$40,000
- Supplies, phone, apps and other costs−$3,800
- 3,000 business miles at the 2026 rates−$2,228
- Profit the tax is figured on$33,973
- Federal tax after write-offs$6,409
- Federal tax if she tracked nothing$7,933
Her write-offs saved her about $1,524. That is roughly $25 for every $100 she wrote down.
The formula in plain words
- Profit = what you earned − every business cost − miles × the IRS mileage rate.
- Self-employment tax = profit × 92.35% × 15.3%.
- Income tax: profit plus any wages, minus half the SE tax and the standard deduction ($16,100 single), then the brackets.
- Savings = the tax with no write-offs − the tax with them.
Why write-offs save more than people think
A write-off lowers two taxes at once. Self-employment tax (Social Security and Medicare) is about 14% of profit. Income tax comes on top, at 10%, 12%, 22% or more. So for most self-employed people, each $100 of write-offs saves somewhere between $14 and $40 in federal tax.
That is why tracking matters. A cost you never wrote down is taxed as if you kept the money.
What counts as a write-off
Money you spend to do your work: supplies, product and tools; the work share of your phone and internet; apps, software and booking fees; booth, suite or office rent; business insurance and licenses; card processing fees; classes for your trade; and miles you drive between jobs.
Personal costs do not count, even if you pay them from the business account. Clothes you could wear anywhere, your commute from home to one regular workplace, and meals on your own are personal. For costs that are part work and part personal, like a phone, count only the work share.
No receipts? Start anyway
Your bank and card statements show the date, the store and the amount. Add a short note on what each cost was for, and that is a usable record for most expenses. Rebuild your miles from your calendar and client list. Then keep it current from here on.
Toozi does this from your texts and your bank. Text "paid $85 for supplies" or connect your bank, and it sorts the write-offs and keeps this number up to date all year.
Stop estimating. Have Toozi keep the running number.
Text your income and expenses as they happen. Toozi keeps your books. It sets aside the right amount from each payment. It texts you before every due date. Then it e-files your return.
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Questions
How much does a $100 write-off save in taxes?
Usually $14 to $40 in federal tax. About $14 comes from self-employment tax. The rest is income tax at your bracket: nothing if your profit is under the standard deduction, $12 in the 12% bracket, $22 in the 22% bracket.
Are write-offs taken off before or after tax?
Before. You subtract business costs from what you earned to get profit, and both self-employment tax and income tax are figured on that profit. That is why the calculator asks for what you earned and your costs separately.
Can I write off mileage and gas?
Not both for the same car. The standard mileage rate already covers gas, insurance and repairs. Parking and tolls are extra. The calculator turns your business miles into dollars at the 2026 rates.
Does this include state tax?
No, it is federal only. Write-offs lower state income tax too in most states, so your real savings are a little higher.
Tax is a doozy.
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