Scotland tax calculator — methodology

Two positions on one income

The calculator calls computeTaxPosition twice, with identical income and a different region, and subtracts. Nothing else about the comparison is modelled here: the engine handles the allowance, the allocation and the stacking order both times.

scotland   = computeTaxPosition({ region: 'scotland',   earned, savings, dividends })
restOfUk   = computeTaxPosition({ region: 'england-ni', earned, savings, dividends })
difference = scotland.total − restOfUk.total

The rest-of-UK region is england-ni rather than wales. Wales has independent rate-setting power and currently sets the same rates, so the two produce the same figure today — which is exactly why the choice is made deliberately rather than left to whichever happened to be first in the list.

What the rules file actually says

The devolution claim on this page is checkable in one file. In packages/tax-core/src/rules/2026-27.ts the region map gives Scotland its own earned-income schedule and hands it the same savings, dividend and capital gains arrays every other region gets:

'england-ni': { earned: ENGLAND_EARNED,  savings: UK_SAVINGS, dividend: UK_DIVIDEND, gains: UK_GAINS },
wales:       { earned: ENGLAND_EARNED,  savings: UK_SAVINGS, dividend: UK_DIVIDEND, gains: UK_GAINS },
scotland:    { earned: SCOTLAND_EARNED, savings: UK_SAVINGS, dividend: UK_DIVIDEND, gains: UK_GAINS },

One array differs. The National Insurance block in the same file is not keyed by region at all, and personalAllowance is a single figure for the whole year — so neither can vary by region even in principle.

Why a UK-rated line can still move between the columns

“Savings and dividends are charged on UK-wide bands” is a claim about rates, and it is exactly true. It does not follow that the tax on them is always identical either side of the border, and a page that promised that could be caught out by its own calculator.

ITA 2007 s.25(2) entitles a taxpayer to deduct allowances in the way that produces the greatest reduction in liability, and computeTaxPosition searches that allocation rather than assuming an order. Which allocation is best depends on the rate schedule sitting under each kind of income — and one of those three schedules is Scottish. So on some income mixes the personal allowance lands on a different pound in Scotland than it does elsewhere, and a savings or dividend line shifts by a few pounds without any rate having changed.

The calculator therefore computes both positions in full and reports the per-income-type figures the engine produced, rather than printing the Scottish number twice under an assumption. On the income the page opens with — £50,000 of earnings, £1,000 of interest and £2,000 of dividends — the totals are £9,718.30 in Scotland and £8,168.25 elsewhere.

The stacking order, which is statutory and not a presentational choice

Income is not taxed in the order it arrives. Earnings are taxed first, then savings interest, then dividends — so each kind starts wherever the one below it finished. On a Scottish page that has one consequence worth stating plainly: the earnings underneath a slice of interest are taxed on Scottish bands, which changes where the interest starts, while the interest itself is charged on UK bands. The devolved schedule reaches the rest of the calculation through the stack, not through the rates.

Rates and allowances

The savings, dividend and gains rows are read from the Scottish region and are the UK schedules. Comparing them with the England, Wales and Northern Ireland row above shows the devolution boundary directly rather than asking the reader to take it on trust. The personal savings allowance is decided by which UK band total taxable income reaches, which is why £1,000 can still be due to somebody paying a Scottish intermediate rate on their salary.

Sources

• gov.uk — Income tax in ScotlandHMRC’s statement of which income the Scottish rates apply to, and that residence rather than workplace decides who is a Scottish taxpayer.
• gov.scot — Scottish income tax rates and bandsThe published page still titles its table “Proposed Bands”. The bands are in force: the Scottish Parliament agreed the Scottish Rate Resolution, motion S6M-20844, on 19 February 2026, and the resolution is the legal authority for the figures used here.
• gov.uk — Income tax rates and allowances: current and pastThe personal allowance and its taper, and the England, Wales and Northern Ireland schedule this page compares against.
• gov.uk — Tax on dividendsThe dividend rates and allowance, which are UK-wide and appear unchanged in both columns.
• gov.uk — Tax on savings interestThe starting rate for savings and the personal savings allowance, both UK figures, and the second of them set by which UK band the taxpayer reaches.

Five things this calculation does not model, stated here rather than buried

• National Insurance. Reserved, identical across the UK, and absent from this page — so the figure it leaves over is not take-home pay, and adding National Insurance would change both columns by the same amount rather than the difference between them. The take home pay calculator for Scotland includes it.
• Capital gains tax. Also reserved. A gain is stacked on taxable income and meets the UK basic-rate band; Scottish bands do not decide which capital gains rate applies. The capital gains tax calculator does that calculation.
• Student loan and postgraduate loan repayments, including Plan 4 — the plan most Scottish graduates repay on, and one whose threshold differs from the plans used elsewhere in the UK.
• Pension contributions. computeTaxPosition takes a pension contribution and extends the rate limits for relief at source, but this page passes neither, so anyone contributing is shown more income tax than they owe — in both columns. The pension tax relief calculator models the band extension.
• Tax codes and the transferable allowances. The standard personal allowance is assumed; the marriage allowance, the blind person’s allowance, benefits in kind and PAYE underpayments all move it. ISA income is tax free and belongs in none of the input boxes.