If you employ anyone in the UK, PAYE Real Time Information (RTI) is the system you use to tell HMRC about pay, tax and National Insurance every single time you run payroll. Unlike the old annual P35 process, you submit data on or before each payday. This guide covers the FPS, the EPS, the payment dates, and the penalties for slipping up. It sits at the heart of running payroll and HR in the UK, and builds on the basics of how PAYE payroll works.
What RTI actually is
RTI is the data feed between your payroll software and HMRC. Each pay run produces one or two submissions:
- Full Payment Submission (FPS) - sent on or before each payday, listing every employee’s pay, tax, NIC, student loan and pension data
- Employer Payment Summary (EPS) - sent monthly when you have adjustments such as statutory pay recoveries, the Employment Allowance, or a nil payroll month
You cannot file by spreadsheet or paper. HMRC requires recognised payroll software, including HMRC’s own free tool for employers with fewer than ten staff. For more on the data feed itself and how each return is structured, see our guide to RTI reporting.
The monthly cycle
| Date | Action |
|---|---|
| On or before each payday | Submit FPS |
| 19th of following month | EPS due (if any adjustments) |
| 22nd of following month | PAYE and NIC payment due (electronic) |
| 19th of following month | PAYE and NIC payment due (postal cheque) |
| 5 April | Tax year end |
| 19 April | Final FPS or EPS for the tax year |
| 31 May | P60s issued to employees |
| 6 July | P11D and P11D(b) due |
| 22 July | Class 1A NIC payment due |
Quarterly payment is allowed if your monthly PAYE bill averages under £1,500.
What goes in an FPS
Each FPS line covers one employee and includes:
- Personal details and NI number
- Pay frequency and payment date
- Gross pay, taxable pay and pay-to-date totals
- Tax code and income tax deducted
- Employee and employer NIC, plus the NI category letter
- Student loan deductions and plan type
- Pension contributions (employee and employer)
- Statutory payments (SSP, SMP, SPP, ShPP, SAP)
- Year-to-date totals across every field
The data flows into the employee’s HMRC personal tax account in near real time, which is why coding notices and starter information must be accurate from day one.
Penalties
| Offence | Penalty |
|---|---|
| Late FPS (1-9 employees) | £100 per month |
| Late FPS (10-49 employees) | £200 per month |
| Late FPS (50-249 employees) | £300 per month |
| Late FPS (250+ employees) | £400 per month |
| Late payment | 1-4% surcharge depending on frequency |
| Inaccurate return | Up to 100% of additional tax due |
The first late FPS in a tax year is usually treated leniently. Repeat offenders face escalating charges and HMRC compliance reviews.
Common RTI mistakes
- Filing the FPS after payday rather than on or before
- Forgetting an EPS for the Employment Allowance claim
- Reporting a leaver after the next pay period rather than on the final FPS
- Using the wrong NI category letter for under-21s, apprentices or veterans
- Failing to reconcile the payroll journal to the FPS each month, leading to year-end mismatches
Year-end and beyond
If you want someone to run payroll for you and post the journals to your books, ask for accounting help.