NHS Pay
NHS Payslip Codes Decoder: Tax Code, NI and ESR Lines
Independent guidance — not affiliated with NHS England or DHSC
Short answer
Most NHS payslips come from ESR, and use a short set of codes. The ones people ask about most: ARRS (arrears), EN (enhancement, such as unsocial hours), OT (overtime), NNI (not subject to National Insurance), NP (non-pensionable), HCAS (High Cost Area Supplement), OSP and SSP (occupational and statutory sick pay), and OMP and SMP (occupational and statutory maternity pay). Your tax code (usually 1257L) and National Insurance category (usually A) are in the header. Exact labels vary by trust, so this decoder lists what trust payslip guides and GOV.UK say and tells you what to check.
Our guide to reading your payslip explains the structure: earnings, gross pay, taxable pay, deductions and net pay. This page is the reference you keep open next to your payslip, to decode individual labels, codes and letters, and to know what to ask when one looks wrong.
The header: who and what you are paid on
These header fields come from trust payslip guides. Layouts differ, but the names are broadly consistent.
| Label | What it means | What to check |
|---|---|---|
| Assignment number | Your payroll reference for pay queries. Has a suffix such as -1 or -2 if you have more than one post | Quote it in every pay query |
| Payscale description | The pay scale you are paid on (for example Agenda for Change) | That it matches your contract |
| Sal/Wage | Full-time annual salary for your band and pay point | Matches the current pay scale |
| PT Sal/Wage | The reduced annual figure if you work part-time | Your contracted hours divided by 37.5 times the full-time salary |
| Standard hours | Your contracted weekly hours | That they match your contract |
| Inc. date | The date of your next pay step, or when you reached the top of your scale | That your increment date is right |
| Tax code | The code HMRC has told your employer to use | See the tax code section below |
| SD reference number | Your NHS Pension reference. Quote it to NHS Pensions | Do not confuse with the assignment number |
Pay and allowances: the codes
The pay section usually has columns for description, hours worked or earned, hours paid or due, rate and amount. Trust guides explain them as: Wkd/Earned is total hours worked, Paid/Due is the number of hours the payment is calculated on, Rate is the amount the payment is calculated on (for example an hourly rate) and Amount is the payment made.
| Code or line | Meaning | Worth checking |
|---|---|---|
| ARRS | Arrears payment, backdated pay | The dates it covers and whether the total matches what you were told |
| EN | Enhancement payment, such as unsocial hours | Hours and rate against your rota; see unsocial hours rates |
| OT | Overtime payment (for example Saturday) | Time and a half beyond 37.5 hours, double time on public holidays (Handbook Section 3) |
| NNI | Payment not subject to National Insurance contributions | Ask payroll which item is being treated this way and why |
| NP | Non-pensionable payment | That items you expect to count towards your pension are not tagged NP |
| HCAS | High Cost Area Supplement for London and surrounding areas | That your zone and percentage are right |
| Fringe | Described by some trusts as an additional category for areas around London | Ask payroll what yours covers |
| R | Refund | What it relates to |
| WTD pay | For bank staff, a supplement of 12.07% of basic pay and enhancements representing statutory holiday entitlement (one trust's description) | That it is calculated on the right pay |
Unsocial hours enhancements in England are worked out on basic salary plus any long-term recruitment and retention premia, and are pensionable (Handbook paragraphs 2.8 and 2.14). If you are not sure whether an enhancement is right, try our free Unsocial Hours Calculator.
Leave, sickness and maternity lines
| Code or line | Meaning |
|---|---|
| AfC Absence | Pay for annual leave, based on your average pay over a reference period, usually the three months ending on the last day of the pay period in which the leave started (one trust's description, consistent with Handbook 13.9) |
| OSP | Occupational sick pay |
| SSP | Statutory sick pay |
| OMP | Occupational maternity pay |
| SMP | Statutory maternity pay |
| ShPL | Shared parental leave |
Two rules explain most surprises on a payslip during sickness. First, occupational sick pay and statutory sick pay together cannot exceed full pay (Handbook 14.6 and 14.8). Second, unsocial hours payments are not payable during sickness absence for staff who first started under the Handbook on or after 1 July 2018, or whose basic pay is above £18,160 (paragraph 2.13), though they are payable for those off with work-related injury or illness who are not receiving injury allowance. See our sick pay guide, our SSP changes guide and the holiday pay and overtime guide for the rules behind these lines.
Tax code letters
GOV.UK describes the common parts of a tax code like this:
| Code | Meaning (GOV.UK) |
|---|---|
| 1257L | The tax code currently used for most people with one job or pension |
| L | Entitled to the standard tax-free Personal Allowance |
| M | Marriage Allowance: you have received a transfer of 10% of your partner's Personal Allowance |
| N | Marriage Allowance: you have transferred 10% of your Personal Allowance to your partner |
| T | Your code includes other calculations to work out your Personal Allowance |
| 0T | Personal Allowance used up, or you have started a new job |
| BR | All income from this job or pension taxed at the basic rate |
| D0 | All income taxed at the higher rate |
| D1 | All income taxed at the additional rate |
| NT | You are not paying any tax on this income |
| K | You have income that is not taxed, more than your Personal Allowance |
| W1, M1, X | Emergency codes, often used when HMRC has not yet given your employer a code, for example for a new starter |
| S or C prefix | Codes for Scottish or Welsh taxpayers, following the same patterns |
A code that is not 1257L is not necessarily wrong: a second job, benefits, or an earlier underpayment can all change it. For new starters especially, emergency codes are common and fixable. Read NHS tax codes explained for how to check and what to do if it is wrong. Source: GOV.UK, what your tax code means.
National Insurance category letters
The letter shows which National Insurance rules apply to you. According to GOV.UK:
| Letter | Who it applies to |
|---|---|
| A | All employees apart from those in groups B, C, H, J, M, V and Z. This is the usual category |
| B | Married women and widows with a certificate of election for reduced National Insurance |
| C | Employees over State Pension age |
| H | Apprentices under 25 |
| J | Employees who can defer National Insurance because they pay it in another job |
| M | Employees under 21 |
| V | Employees in their first job since leaving the armed forces |
| Z | Employees under 21 who can defer National Insurance because they pay it in another job |
GOV.UK also lists categories F, I, L and S for employees working in special tax sites in Freeports. Source: GOV.UK, National Insurance category letters. If your letter does not fit your situation (for example you are over State Pension age but on A), ask payroll to check it.
Pension and other deductions
- NHS Pension contribution: shown as a percentage and cash amount, set by a contribution tier that depends on your pensionable pay. Check the percentage against the tier table in our pension scheme guide. Pension contributions are taken before Income Tax is calculated, which is why taxable pay can be lower than gross pay.
- Student loan: shown as its own line when your income is above the threshold for your plan, based on the plan HMRC holds. See student loan repayments.
- Other deductions: union subscriptions, parking, Cycle to Work or other salary sacrifice schemes, and recovery of an overpayment can all appear. For overpayments, see your rights if you are overpaid.
Year to date and this period
Trust payslip guides describe two summary blocks. Year to date balances show total amounts received and deducted so far in the tax year, and the PAYE details feed into your P60. This period summary shows the totals for the current pay period, the date you will be paid, how, and the net pay. Keep an eye on the year-to-date tax and National Insurance if you change jobs or have a second job.
Common problems and what to ask
- ✓ Emergency tax code (W1, M1, X, or 0T): ask HMRC to confirm your code; payroll applies what HMRC sends
- ✓ BR or D0 on your only job: likely wrong; contact HMRC
- ✓ Enhancements missing or low: compare EN lines with your rota, then ask payroll for the hours and rate used
- ✓ Arrears with no explanation: ask what period and rate they cover
- ✓ Pension percentage looks wrong: check your tier and whether your pensionable pay changed
- ✓ NI letter does not fit you: ask payroll to confirm it with HMRC records
- ✓ Pay dropped in sickness: check your sick pay entitlement and whether unsocial hours payments stop for your contract
- ✓ Leave pay lower than normal: ask how the reference period and regular overtime were applied
Run your numbers through the free NHS Payslip Checker, which compares your pay with what you should expect for your band and pay point.
NHS Payslip Checker
Check your payslip figures against the expected pay for your band, point and hours.
ℹSources and limits
Abbreviations and header fields come from published NHS trust payslip guides, which use the ESR layout; tax code and National Insurance letters from GOV.UK; unsocial hours and sickness rules from the NHS Terms and Conditions of Service Handbook (England). Layouts and labels differ between trusts, and some local codes are not listed here, so your payroll team has the final say on what a given line means. FrontlinePay is not affiliated with the NHS or any trust.
Related guides and tools
How to Read Your NHS Payslip
The stages from earnings to net pay.
NHS Tax Codes Explained
Emergency codes and how to fix a wrong one.
NHS Payslip Checker
Free check of your pay for your band and point.
NHS Unsocial Hours Payments Explained
The enhancement rates behind EN lines.
NHS Sick Pay Explained
OSP entitlement by length of service.
NHS Overpayment of Wages: Your Rights
If a deduction recovers an overpayment.
How to Get Your P60 and P45 as NHS Staff (ESR)
Getting your P60 and P45 from ESR, the 90-day Leavers Dashboard and what to do if lost.
Frequently asked questions
What does ARRS mean on an NHS payslip? +
What do EN, OT, NNI and NP mean? +
What does HCAS mean, and what is Fringe? +
What does the -1 or -2 after my assignment number mean? +
What is the WTD pay line? +
My payslip shows a tax code with BR or D0. Is that right? +
What does the NI letter mean, and is A normal? +
Why did my pay drop when I was off sick? +
What is the SD reference number? +
Who do I ask if a code or amount looks wrong? +
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