Freelance taxes: how much to set aside
A reserve calculator for an author who is paid fees and is responsible for their own tax. You enter the income for a period and how it is taxed, and the tool shows the amount payable, what is left in hand, the effective rate and, most importantly, what share to set aside from every payment so that you are not scrambling for money at the end of the quarter. One thing up front: this is not tax advice and not a reference on the rules in force. It is arithmetic on numbers you entered yourself. Rates, thresholds and contributions change every year, differently in every country, and the US and UK templates in the tool are only prefilled fields that have to be checked against a current source — the IRS or HMRC. US state and city income tax are outside the tool altogether, and so are the UK personal allowance and the National Insurance thresholds.
This is not tax advice. The tool does arithmetic on numbers you entered yourself, and it knows nothing about your country, your status or your contract. Rates, thresholds and contributions change every year and differ from one jurisdiction to another. US state and city income tax are out of scope entirely, and so are the UK personal allowance and the National Insurance thresholds — the tool models none of them, so where they apply its figure is wrong in a predictable direction. Before you pay anything, check against the law in force or with an accountant.
Templates to start from
Your numbers
Scale brackets
| Annual base from you must enter the current thresholds yourself — they are indexed every year | Rate, % | Remove |
|---|
How much to set aside
Share of income that goes to the state
Line-by-line calculation
| What is counted | Base | Rate | Amount |
|---|---|---|---|
| Enter your income and every step of the calculation appears as its own row. | |||
Your income figures never leave your browser: the calculation runs on your device, nothing is sent anywhere and nothing is stored.
Why this is a calculator and not advice
The tool knows neither your country, nor your filing status, nor which expenses you are allowed to deduct, nor whether you fall within the limit of the regime you picked. It does not track changes in the law and is not updated every year along with the budget. The four templates — US self-employment tax, US self-employment tax with a 22% federal bracket, UK Self Assessment at the basic rate, and your own setup — are prefilled fields carrying figures as of 2025. They exist so that you do not have to type five fields from scratch, and none of them locks anything: the moment you edit any figure, the template mark is cleared. Do not read them as a description of the law in force. Each template is honest about what it leaves out, and the gaps are large. The 15.3% self-employment tax really applies to about 92.35% of net self-employment earnings rather than to the whole profit, and its Social Security half stops at an annual wage base that the tool does not model. Federal income tax is progressive and comes after the standard deduction, so the flat 22% in the second template overstates it. State and city income tax are not in the tool at all. On the UK side the personal allowance and the National Insurance thresholds are not modelled either, which makes the figure too high for small profits. Where a number would have been a guess — every progressive-scale threshold, for instance — the field is left empty on purpose and the tool refuses to calculate until you fill it in. The practical rule: before you pay, check the rates against an official source — the IRS or HMRC — or with an accountant, and use the calculator for what it was built for: to see the structure of the amount and avoid spending money that is not actually yours.
Three ways to calculate and how they differ
Percentage of turnover is the simplest: the rate is taken from the whole amount that came in, and expenses are not counted at all. That suits an author working under a flat-rate regime, or anyone with almost no deductible expenses. Percentage of profit takes the rate from the difference between income and expenses, and that is the mode all three ready-made templates use, because both US self-employment tax and UK Self Assessment are charged on net earnings rather than on gross receipts. An expenses field appears here, and the whole amount depends on what you are entitled to put into it. The tool checks the legality of no expense line at all; it simply subtracts a number. It applies no standard deduction, no personal allowance and no 92.35% adjustment of its own — if you want any of those, they go into the expenses field yourself. The progressive scale allows up to seven brackets of threshold plus rate, which is how many ordinary rates the US federal schedule has. It opens with those seven rates — 10, 12, 22, 24, 32, 35 and 37% — and with the thresholds blank, because the brackets are indexed every year and depend on the filing status. That blank is the point: the tool will not calculate until you have taken the current schedule from the IRS, or the bands from HMRC, and typed the thresholds in yourself. Thresholds are set for the annual base, the way laws state them: if your period is a month or a quarter, the tool scales the base up to a year, spreads it across the brackets and brings the amount back to your period. If the first bracket does not start at zero, everything below that threshold is untaxed, which is what a standard deduction or a personal allowance looks like in this model. Two fields stand apart from the regime: the fixed monthly contribution, for a flat charge you pay regardless of profit, and the additional rate in percent, taken from the same base. In the US templates the additional rate is where federal and state income tax go, on top of the self-employment tax; in the UK template it carries Class 4 National Insurance on top of income tax. Neither self-employment tax nor National Insurance is a flat monthly amount, so the fixed contribution field stays at zero in all three.
Why you have to set aside more than the rate
The most common mistake a beginning author makes is to look at one rate and set that percentage aside. Someone who sees 15.3% self-employment tax and reserves fifteen percent of every fee has forgotten federal income tax, and quite possibly state income tax as well; with a 22% bracket on the same profit the real share leaving the account is closer to 37%. A flat monthly contribution, if you have one, works the same way: it does not depend on how much you earned, so in a weak month it is precisely what pushes the effective rate up. So the tool shows the rate and the effective rate separately, the effective rate being everything you hand over divided by all of your income. The percentage on the card that says to set aside from every payment is the effective rate rounded up to a whole number. Under-reserving is worse than setting aside too much: the surplus stays with you, whereas a shortfall has to be covered out of the next fee. The line-by-line table exists precisely so that you can check every step by hand instead of taking the final figure on trust. If some row looks odd, that is exactly where the input needs fixing.
What the calculator does not do
It files no returns, calculates no interest or penalties for late payment, knows nothing about income limits above which a regime changes by itself, and does not account for tax withheld by the client at the moment of payment. It does not schedule US quarterly estimated payments or UK payments on account, and it applies no safe-harbour rule. Specifically for the two jurisdictions its templates cover: US state and city income tax are out of scope entirely, the Social Security wage base that caps part of the self-employment tax is not modelled, and neither is the 92.35% adjustment or the deduction for one half of the self-employment tax. On the UK side the personal allowance, the Class 2 and Class 4 National Insurance thresholds and the higher-rate and additional-rate bands are not modelled either. In both directions that makes the figure wrong in a way you can predict: too high on small profits, too low once thresholds and caps would have started to matter. It does not work with exchange rates: the currency selector only chooses a symbol and where it is printed, so income in several currencies has to be brought to one currency by you. It does not separate income from different sources with different rules, and it knows nothing about double taxation treaties. And it stores nothing as a matter of principle: your income figures never leave your browser, are not written to storage and are not sent anywhere. Close the tab and everything you entered is gone.