How is D0 different from BR?

BR applies 20% to all pay; D0 applies 40%. HMRC moves you from BR to D0 when they see your total income is already in higher-rate territory - it's a more accurate collection at source.

Why am I on D0 instead of BR?

Because HMRC believes your main job has already used both your Personal Allowance and your full £37,700 basic-rate band, so anything additional belongs at the 40% higher rate. Applying BR (20%) to the second job in that situation would leave you owing the extra 20% at year-end through Self Assessment; D0 collects the right 40% at source instead.

It can. D0 over-taxes you if your total combined income actually falls below £50,270 - you would be paying 40% on the second job when your overall liability only justifies 20%. HMRC reconciles this automatically at year-end via a P800 and refunds the excess, but you can recover it sooner by asking HMRC to re-code the second source to BR or 0T mid-year.

Do D0 and D1 work in Scotland?

Scotland uses its own D-codes because it has more bands: SD0 applies the intermediate rate (21%), SD1 the higher rate (42%), SD2 the advanced rate (45%) and SD3 the top rate (48%). So the Scottish equivalent of a rest-of-UK D0 (flat 40%) is SD1 (flat 42%). The mechanism is identical - a flat rate with no allowance on a second income - only the rate follows the Scottish bands.

I'm only on D0 - does that mean I'm taxed 40% on everything?

D0 applies only to pay from that source (usually a second job or pension). Your primary source keeps its own tax code, typically 1257L with the usual basic-rate band below higher rate.

Can D0 change back to BR or 1257L?

Yes. If your main income drops below the higher-rate threshold, HMRC normally downgrades additional-source codes to BR. Contact HMRC if the code doesn't update automatically after a circumstance change.

Tax Code · 2026/27

D0 Tax Code: Higher-Rate (40%) on Every Pound UK 2026/27

D0 applies a flat 40% higher-rate to all pay from this source. HMRC uses it when they believe your total income already sits above the basic-rate band.

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What the D0 tax code means

The D0 tax code taxes 100% of pay from this source at the higher rate — currently 40% in England, Wales and Northern Ireland. No Personal Allowance is given because HMRC assumes it's used on your primary income.

It's the next step up from BR: HMRC applies D0 when your primary job has already filled the basic-rate band (income over £50,270 in 2026/27) and this additional source pushes you into higher-rate territory.

D0 avoids an under-payment scenario where a second job taxed at BR (20%) would leave you owing the extra 20% at year-end. By collecting 40% at source, HMRC keeps PAYE accurate across both employments.

How to read it: D signals a flat deduction at one of the higher band rates, and the 0 means the 40% higher rate (D1 means the 45% additional rate). There is no number, so no allowance - the whole source is taxed. In Scotland the equivalent flat higher-rate code is SD1 (42%); note the Scottish D-codes are numbered differently because Scotland has more bands - SD0 is the intermediate rate (21%), SD1 the higher rate (42%), SD2 the advanced rate (45%) and SD3 the top rate (48%). Welsh taxpayers use CD0 (40%, currently identical to the rest of the UK).

When you'll see D0

You have a well-paid second job and your main income already exceeds £50,270/year.
You receive a company pension while still employed in a higher-rate role — the pension can be coded D0.
You're a director with salary plus board fees — the fees are sometimes coded D0 to collect the higher rate at source.

What to do if you have a D0 code

Confirm with HMRC that your main employment is using 1257L and that this second source is correctly identified as additional.
If your circumstances change (main job ends, salary drops) and D0 is no longer appropriate, call HMRC on 0300 200 3300 or update details via your Personal Tax Account.
If you're on D0 but your total income won't exceed the higher-rate threshold this year, HMRC will normally refund the over-tax at year-end.
If the D0-coded job now pays more than your main job, ask HMRC to rebalance the Personal Allowance and lower bands onto the higher-earning role so less tax is collected at source overall.

Worked example

£15,000 second-job income on D0 while your main job pays £60,000 (already in higher-rate territory). Income Tax on the second job is 40% × £15,000 = £6,000. Without D0 (e.g. on BR at 20%), you'd pay only £3,000 here and owe £3,000 at year-end through self-assessment. A larger £20,000 D0 second job pays 40% × £20,000 = £8,000 Income Tax plus its own Class 1 NI of £594.40; had it been mis-coded BR, only £4,000 would be collected - a £4,000 under-payment for HMRC to chase later.

Want to see the numbers for your own salary? Use the salary calculator and pick 2026/27 to see how D0 interacts with your full take-home.

Frequently asked questions about D0

How is D0 different from BR?: BR applies 20% to all pay; D0 applies 40%. HMRC moves you from BR to D0 when they see your total income is already in higher-rate territory - it's a more accurate collection at source.
Why am I on D0 instead of BR?: Because HMRC believes your main job has already used both your Personal Allowance and your full £37,700 basic-rate band, so anything additional belongs at the 40% higher rate. Applying BR (20%) to the second job in that situation would leave you owing the extra 20% at year-end through Self Assessment; D0 collects the right 40% at source instead.
Will D0 over-tax me?: It can. D0 over-taxes you if your total combined income actually falls below £50,270 - you would be paying 40% on the second job when your overall liability only justifies 20%. HMRC reconciles this automatically at year-end via a P800 and refunds the excess, but you can recover it sooner by asking HMRC to re-code the second source to BR or 0T mid-year.
Do D0 and D1 work in Scotland?: Scotland uses its own D-codes because it has more bands: SD0 applies the intermediate rate (21%), SD1 the higher rate (42%), SD2 the advanced rate (45%) and SD3 the top rate (48%). So the Scottish equivalent of a rest-of-UK D0 (flat 40%) is SD1 (flat 42%). The mechanism is identical - a flat rate with no allowance on a second income - only the rate follows the Scottish bands.
I'm only on D0 - does that mean I'm taxed 40% on everything?: D0 applies only to pay from that source (usually a second job or pension). Your primary source keeps its own tax code, typically 1257L with the usual basic-rate band below higher rate.
Can D0 change back to BR or 1257L?: Yes. If your main income drops below the higher-rate threshold, HMRC normally downgrades additional-source codes to BR. Contact HMRC if the code doesn't update automatically after a circumstance change.

All UK tax codes →

Sources & further reading

All figures and definitions on this page reflect the 2026/27 UK tax year and are cross-checked against HMRC guidance.

HMRC — What your tax code means (official meanings for L, BR, D0, D1, K, 0T, NT, M, N, S, C, T)
HMRC — Income Tax rates and Personal Allowance (2026/27 bands and thresholds)
HMRC — Emergency tax codes (W1, M1 and X suffixes)
HMRC — Rates and thresholds for employers 2026 to 2027
HMRC — Your Personal Tax Account (check your current code and how it was calculated)
Our methodology & calculation sources →