What does the D0 tax code mean?
D0 means: D0: all of this income is taxed at the higher rate (40%). Used for a second income when your main job already uses your bands. In short: all income taxed at higher rate. A UK tax code is the instruction HMRC sends your employer for the 2026/27 tax year (6 April 2026 to 5 April 2027): it sets how much of your pay is tax-free before income tax is deducted through PAYE, so the code on your payslip directly decides your take-home. The standard code for most employees with one job is 1257L, worth £12,570 of tax-free income a year, any other code should have a reason behind it (a company benefit, a second job, an HMRC adjustment), and a code that's wrong for your situation means paying the wrong tax every single payday until it's fixed. Decoded below against HMRC's rules as checked on 2026-08-28, with what D0 costs or saves against the standard code.
Decoded
On a £32,000 salary, D0 deducts roughly £8,914.00 more income tax per year than the standard 1257L code, £742.83 a month. If this is your only job and nothing explains the code, that is money to reclaim.
When D0 is correct, and when it is costing you
D0 is a flat instruction to payroll: no allowance, and one rate on every pound of this income, with no bands at all. It is the right code only when the threshold it assumes has genuinely been used up by another job or pension. For D0 that threshold is £50,270, the point where the higher rate starts, so D0 assumes your other income already fills the basic rate band as well as the allowance.
Where it goes wrong is the case the code cannot see. On £32,000 as your only income D0 charges £8,914.00 more income tax a year than 1257L would, because the allowance it assumes is in use somewhere else is not in use at all. D0 is rarer than BR and costlier when wrong, because it charges 40% on income that may not even reach the basic rate ceiling.
How do I find out what code I should be on?
Your current code is on every payslip and on your P60, and the reasoning behind it is in your HMRC personal tax account, which lists the allowances and deductions that produced the number. If the account shows an estimate that is out of date, a company benefit you no longer have or a job you have left, you can change it there and a new code reaches your employer within a few weeks. Employers cannot change a code themselves: they apply whatever HMRC issues, so the fix always runs through HMRC rather than payroll.
Check your own code
Type any code, this page's and every other format HMRC issues:
Tax-free allowance of about £12,570.00 a year.
- L: you get the standard personal allowance.
Other codes people look up
2026/27 rules, checked 28 August 2026 by Hadi. If your code looks wrong, correct it via your personal tax account on gov.uk, refunds for the current year arrive through your pay automatically.