2025 self-employment tax calculator

Why you might be filing 2025 now

A closed tax year stays open for a surprisingly long time, and none of these are unusual situations:

• You filed an extension — a 2025 return on extension is due 15 October 2026.
• You are filing late. The late-filing penalty stops growing once the return is in.
• You are amending on Form 1040-X, which you can generally do for three years.
• You need last year’s total tax to work out this year’s safe harbour.

In every one of those cases the return has to be computed on 2025 rules. Using this year's brackets on last year's income produces a number that is wrong in a way that is hard to spot, because it looks entirely reasonable.

The 2025 standard deduction most calculators still get wrong

Tax year 2025 was legislated twice, and a lot of published calculators only noticed the first time.

The IRS set the 2025 inflation adjustments in Rev. Proc. 2024-40, published October 2024. Then the One Big Beautiful Bill Act, signed on 4 July 2025, raised the standard deduction for that same already-announced year:

A calculator still showing $15,000 was built from the October 2024 release and never revisited. It overstates taxable income by $750 for every single filer, and by $1,500 for a couple filing jointly — roughly $90 to $350 of tax that is not owed, depending on the bracket. The figures above are taken from the IRS instructions for Form 1040 itself, under “What’s New → Standard deduction amount increased”.

Worth knowing what OBBBA did not do to 2025: it left the brackets alone. The extra inflation adjustment to the 10% and 12% bands starts in 2026. It also left the QBI deduction on its old footing for 2025 — the phase-out range is still $50,000 (single) and $100,000 (joint), and the $400 minimum deduction does not exist yet. And the 23% QBI rate that circulated widely in mid-2025 was in the House bill and was dropped before the Act passed. It is 20% in both years.

What changed between 2025 and 2026

Everything below moves the answer. This is why the two calculators are separate pages rather than one page with a dropdown that quietly swaps a couple of numbers.

Put together, on $80,000 of net profit as a single filer with no other income, total federal tax comes to $16,691 for 2025 against $16,647 for 2026 — a difference of $43. Both figures come from the same engine that powers the calculator above, so they cannot drift from what it tells you.

2025 quarterly due dates

These have all passed. They matter now only for working out an underpayment penalty, which is calculated per quarter rather than on the year as a whole — paying the whole balance in December does not undo a shortfall from April.

Q2 that year fell on 16 June, not the 15th — 15 June 2025 was a Sunday, so the deadline rolled to the next business day. Calculators that hard-code “June 15” get this wrong every few years.

How self-employment tax works

When you work for someone else, Social Security and Medicare cost 15.3% of your pay — but you only ever see half of it. Your employer pays 7.65% and you pay 7.65%, and the employer's half never appears on your payslip.

Working for yourself, you are both parties. That is what self-employment tax is: the whole 15.3%, and it is separate from and on top of income tax. It is also why a $80,000 profit feels so much worse than an $80,000 salary.

The 92.35% that confuses everyone

You do not pay SE tax on your full profit. You pay it on 92.35% of it. That number exists to level things up with employees: an employer's half of payroll tax is a deductible business expense, so the law lets you exclude the equivalent slice — 7.65% — before the tax is applied. Hence 100% − 7.65% = 92.35%.

So on $60,000 of profit you owe SE tax on $55,410, not $60,000. It is a small mercy, but it is worth about $700.

The two halves, and where they stop

• Social Security, 12.4% — only on the first $176,100 of earnings in 2025. Above that it stops entirely. The most anyone pays is $21,836.
• Medicare, 2.9% — on everything, with no cap at all.
• An extra 0.9% Medicare surtax above $200,000 (single) or $250,000 (married filing jointly). Unlike the rest, this one is not deductible.

This is why high earners see their effective rate fall: once you pass the wage base, each additional dollar of profit is taxed at 2.9% for self-employment purposes instead of 15.3%.

The deduction most calculators skip

Half of your self-employment tax is deductible from your income — an above-the-line deduction, so you get it whether or not you itemise. It does not reduce the SE tax itself, but it lowers the income your federal tax is calculated on.

Plenty of quick calculators quote you 15.3% and stop there. That overstates what you actually owe, sometimes by more than a thousand dollars, because it ignores both this deduction and the QBI deduction below.

The QBI deduction

Since 2018, most self-employed people can deduct up to 20% of their business income before income tax is calculated. It is one of the largest deductions available to a freelancer and it requires no spending, no receipts, and no election — you simply qualify.

For 2025 the full 20% is available while taxable income stays under $197,300 (single) or $394,600 (married filing jointly). Above that it phases out over the next $50,000 or $100,000.

This calculator assumes you are a sole proprietor with no employees and no significant business property, which is true for most freelancers. If you have staff on payroll, the phase-out rules work differently in your favour and you should talk to an accountant — the deduction may be worth considerably more than shown here.

Why quarterly payments exist

Employees have tax taken from every payslip. Nobody does that for you, so the IRS asks for it four times a year instead. Miss them and you owe an underpayment penalty — which is really just interest, currently charged at a rate that makes ignoring it expensive.

The figure above splits your expected federal bill into four. In practice, income rarely arrives evenly, and you are allowed to pay what you actually owe for each period rather than a flat quarter — that is what Form 2210's annualised method is for.

The safe harbour worth knowing

You can avoid the penalty entirely without predicting your year accurately. Pay either 90% of this year's tax, or 100% of last year's total tax (110% if your prior-year AGI was over $150,000), and you are protected no matter how much you end up earning.

For a good year following an ordinary one, the prior-year route is usually both cheaper up front and far less stressful — you take last year's total tax from your return, divide by four, and stop worrying about it. The safe harbour calculator works out the exact figure, including the part most tools get wrong: you owe the lesser of the two tests, not the prior-year one regardless.

What this calculator does not cover

• State and local tax. Federal only. Depending where you live this can add anywhere from nothing to more than 10%. The take-home pay calculator adds your state.
• Credits. Child tax credit, education credits, energy credits and the rest can reduce your bill substantially.
• Retirement contributions. A SEP-IRA or solo 401(k) can shelter a large share of profit and is one of the most effective levers available to you — see the contribution calculator.
• Self-employed health insurance, which is deductible above the line.
• S-corp election, which changes the picture entirely once profit is consistently high. The S-corp calculator shows where the crossover falls for your numbers.

Each of those pushes the real number down, so treat this as a sensible upper bound for federal tax — and add your state on top.

Is this an estimate or the real thing?

The self-employment tax figure is exact: it is a fixed formula and this calculator applies it in full, including the wage-base cap, the W-2 interaction and the surtax. The income tax figure is an estimate, because it depends on credits and circumstances no calculator can see.

It is not tax advice, and it cannot account for everything. For anything consequential, speak to a qualified professional.

Where the 2025 figures come from

• IRS Rev. Proc. 2024-40 §2.01 — 2025 rate tables, all four filing statuses
• IRS Rev. Proc. 2024-40 §2.27 — 2025 §199A thresholds and phase-in ranges
• IRS Instructions for Form 1040 (2025) — standard deduction as amended by OBBBA
• SSA — 2025 Social Security wage base, $176,100
• IRS Notice 2024-80 — 2025 retirement plan contribution limits
• IRC §6654 — estimated tax safe harbour shares and thresholds