Calendar years, tax years and when tax is paid

A calendar year runs from 1 January to 31 December. A UK tax year runs from 6 April to 5 April. Choosing which one to view changes how figures are grouped, not the figures themselves.

Tax is always worked out for the tax year that the income or gain belongs to, whichever view you choose.

On the Tax page you can choose 2027/28 (Future), 2026/27 (Current), or 2025/26, 2024/25 and 2023/24 (Completed). Each year uses its own published rates and allowances. 2023/24 differs from later years in three ways: the dividend allowance was £1,000 (£500 from 2024/25); the Capital Gains Tax Annual Exempt Amount was £6,000 and residential property gains were taxed at 18% or 28%; and employee National Insurance fell from 12% to 10% on 6 January 2024. Because NI depends on when you were paid and FLYNQD only holds your annual pay, 2023/24 employee NI isn’t calculated; the Tax page says so, and your P60 shows what was deducted. Income Tax for 2023/24 is calculated and has been checked, in automated tests, against an anonymised HMRC calculation (see “Completed tax years: 2023/24, Gift Aid and VCT” below). For a completed year, the Employment income card asks for your actual pay for that year, and the estimate uses it, never today’s salary; choose “I had no employment income” if you had none. Saving it doesn’t change your current salary or your forecast. For a completed year you can also enter the Income Tax HMRC says was due, from your SA302 tax calculation. FLYNQD compares it with its own Income Tax figure, like for like, and shows the actual difference, however small. HMRC’s figure is never used to change FLYNQD’s calculation, and if FLYNQD can’t yet work out its own figure, no comparison is shown. The estimate uses that year’s rates and the figures you entered for that year; each year keeps its own figures. Your choice is remembered on this device, and the current tax year is used if nothing is saved. A figure you haven’t added is never treated as £0, so the estimate stays partial and says what’s missing; enter £0 if you genuinely had none. Which country’s tax rules apply to you is confirmed for each person and each tax year, and is saved with your plan on this device, along with the figures you enter for each year, so it’s still there after a reload, a new tab or restarting your browser. It’s never taken from your address or copied from another year; if you’ve confirmed it for another year, or your personal details name a nation, we suggest it and you choose whether to use it. If your date of birth is saved, we work out whether you’re over State Pension age for the year; otherwise we ask, and keep your answer for that person and year. This only decides whether employee National Insurance applies — it doesn’t mean you get a State Pension. If you explore a plan from your history that was saved before tax answers were part of the plan, applying it keeps today’s tax answers and figures rather than leaving them blank, and we tell you so.

Your current balances are valued on a date. The forecast starts from that date, so nothing before it is counted again.

A tax liability is what you owe for a tax year. A tax payment is the money leaving your account to settle it. The tax is counted once, when it arises; paying it moves cash but is not a second cost.

Tax on salary and most pensions is usually taken through PAYE before you are paid. Other income, such as self-employment, rent, dividends or gains, is usually paid through Self Assessment by 31 January after the tax year.

If your Self Assessment bill is £1,000 or more and less than 80% of your tax was collected at source, you normally also make two payments on account towards the next year, on 31 January and 31 July.

Choosing when to take a taxable step, such as a pension withdrawal or a sale, can change how much tax you owe. Choosing when to pay a bill you already owe only changes when the cash leaves, and paying after the deadline can add interest and penalties.

Completed tax years: 2023/24, Gift Aid and VCT

2023/24 rules: Personal Allowance £12,570, basic rate 20% up to £37,700 of taxable income, higher rate 40%, additional rate 45% above £125,140. Dividends: £1,000 allowance, then 8.75%, 33.75% and 39.35%. The £5,000 starting rate for savings and the £1,000/£500 Personal Savings Allowance apply as in later years.

Gift Aid band extension: a Gift Aid donation is treated as paid after basic-rate tax, so the gross amount is what you paid × 1.25. Your basic-rate band (and higher-rate limit) is extended by that gross amount, which can move income from higher-rate to basic-rate tax.

Donations versus tax bands: on an HMRC calculation, the extension (for example £1,250) and the new basic-rate limit (for example £38,950) are band figures, not donations. FLYNQD only reads the extension as Gift Aid, asks you to confirm it, and never treats the band limit or a Gift Aid charge as a payment you made.

Gift Aid tax-cover charge: the charity reclaims basic-rate tax on your donation, so you must have paid at least that much tax. If your Income Tax and Capital Gains Tax for the year, after reliefs, are less than 20% of the gross donation, HMRC charges the difference. In the anonymised reference case, VCT relief reduced Income Tax to nil, so a £53.00 charge was due on gross Gift Aid of £265.

VCT relief: relief is 30% of the amount subscribed, up to £200,000 a year. It only reduces Income Tax to nil; any excess is lost, not refunded or carried forward. FLYNQD caps it at the tax due and never shows negative tax.

Capital Gains Tax: the Capital Gains Tax you entered for the year counts towards covering the Gift Aid charge. FLYNQD doesn’t yet widen the basic-rate band for gains to reflect Gift Aid or pension contributions, so the Capital Gains Tax section asks you to check those rates rather than guess.

Rounding: HMRC rounds each tax line down to the penny (for example £1,782.725 becomes £1,782.72), and FLYNQD does the same on completed-year calculations. Small differences of a few pence on other documents can still come from HMRC rounding we haven’t seen.

Not supported yet: 2022/23 and earlier; Scottish and Welsh rate differences beyond those held for each year; 2023/24 employee National Insurance; the Gift Aid band extension for Capital Gains Tax rates; Gift Aid carried back to the previous year; Enterprise Investment Scheme and Seed EIS relief; married couple’s allowance; and the High Income Child Benefit Charge. Where these apply, the estimate stays partial and says why.

What FLYNQD does today

You can choose Calendar year or UK tax year in Settings. The choice applies across FLYNQD and is kept on this device. A single view can switch temporarily without changing your setting.

Your forecast is still calculated in calendar years. Where a figure is shown by tax year, a yearly amount is split by the number of days in each period and marked as estimated. Balances at 5 April aren't shown, because the forecast only knows balances at 31 December.

Every forecast year currently uses the 2026/27 tax rates and allowances. FLYNQD now keeps tax rules for each tax year, including the announced 2-point rise in tax on savings interest from 6 April 2027, but your forecast doesn't use them yet. Where no rules have been published for a year, FLYNQD will say it is assuming the latest rules continue, rather than guess.

Working out tax on the actual tax year each payment falls in, using your pay dates and the dates of one-off receipts, is being built and checked. It isn't used in your forecast yet.

FLYNQD currently estimates Income Tax on salary, State Pension, pension and other income you enter, and pension withdrawals, and National Insurance on employment income. Savings interest and dividends are taxed when you enter them as an income with that tax type. Interest and growth on your account balances aren't taxed. For 2023/24, 2024/25 and 2025/26 you can record disposals on the Tax page and FLYNQD estimates Capital Gains Tax on them, separately from Income Tax (see “Capital Gains Tax: gains, losses and rates”). Capital Gains Tax isn't part of your forecast, and Corporation Tax and Inheritance Tax aren't calculated. FLYNQD holds the Scottish rates for each supported year, but doesn’t yet estimate tax for Scottish taxpayers; the Tax page says so rather than using the rest of the UK’s rates.

On the Tax page, rent from properties you own is shown for the person you're viewing, using your Property records: rent after empty periods, allowable costs (not the mortgage), and an estimated taxable profit, split by each person's share. This property profit isn't added to the tax estimate yet, so the page is marked as a partial estimate and tells you how much is left out. When combined property and dividend tax is switched on, it is only used if everything checks out: the tax year and your part of the UK are supported, there's one property source, joint shares are confirmed, the letting costs, mortgage figures and property location are known, and the result matches the current calculation on your other income. If anything is missing, the page names it and stays partial. If you also typed a property figure into this tax year's figures, you choose which one to use, so the same rent is never counted twice. Tax is shown one person at a time; there's no combined household tax figure.

If your plan has a valuation date, the first forecast year only charges tax for the rest of the tax year, using the full year's allowances and bands. If you enter the tax already taken from your pay this year, FLYNQD uses it; if not, it estimates it and says so. Plans without a valuation date are still charged a full year of tax in the first year.

Employee National Insurance is worked out on your yearly pay. In reality it is worked out each pay period, so a one-off bonus can mean you pay less than FLYNQD shows. Directors, who are assessed yearly, are shown correctly. National Insurance on self-employed profits isn't calculated.

Self Assessment payments on account and balancing payments aren't in your forecast yet. If you pay tax this way, the timing of tax in your forecast will differ from your real payment dates. When you check a tax calculation document, FLYNQD shows the payments it contains under “Your HMRC payments” (see “Checking a tax calculation document”).

Balancing payments and payments on account

A tax liability is how much tax a year produces. A payment is when cash goes to HMRC. They're shown separately, so the same tax is never counted twice.

The balancing payment is what's left of a year's Self Assessment bill after any payments on account already made for that year. It's due by 31 January after the tax year ends: 31 January 2027 for 2025/26.

Payments on account are two advance payments towards the next year's tax, each normally half of this year's Self Assessment Income Tax and Class 4 National Insurance. They're due on 31 January and 31 July. For example, a 2025/26 calculation can show payments on account for 2026/27 due on 31 January 2027 and 31 July 2027. They aren't extra tax: they're credited against 2026/27, and HMRC adjusts them once that year is calculated.

No payments on account are needed if that Self Assessment bill is under £1,000, or if 80% or more of your tax was collected at source, such as through PAYE. Capital Gains Tax and student loan repayments are never included.

Payment amounts can differ from the tax liability because of payments already made, tax taken at source, a claim to reduce payments on account, an amended return, interest or penalties.

What FLYNQD doesn't model yet

After the first year, tax is still worked out on calendar years, using 2026/27 rules for every year, and deducted in the year it arises, as if all of it were taken at source. Calculating on true tax years with each year's rules, per-pay-period National Insurance, Self Assessment payment dates and owed tax in your net worth are planned.

Explore in your plan

• See your tax estimate
• Open your forecast

Related guides

• Tax in retirement
• Capital Gains Tax: gains, losses and rates
• Checking your tax against HMRC's figures
• Assumptions, inflation and uncertainty