RTI — Real Time Information — is the system that employers use to report payroll information to HMRC every time employees are paid.
It’s one of the most important parts of UK payroll, and late or incorrect submissions can lead to penalties.

This guide explains RTI in simple terms so you understand what it is, how it works, and what you must do as an employer.

What Is RTI?

RTI stands for Real Time Information.
It’s the process of sending payroll data to HMRC on or before the day employees are paid.

RTI tells HMRC:

How much each employee has been paid
What tax and National Insurance has been deducted
Whether statutory payments have been made
Whether the employer has made any recoveries or adjustments
How much PAYE/NIC the employer owes

Without RTI, HMRC wouldn’t know how much tax or NI an employee should pay.

Why RTI Matters

RTI helps HMRC:

Track tax and NI in real time
Issue accurate tax codes
Prevent over- or under-payments
Monitor employer compliance
Apply Universal Credit assessments correctly
Reduce payroll errors across the country

For employers, RTI is a legal requirement every time payroll is run.

The Two Core RTI Submissions: FPS and EPS

There are two main RTI submissions employers must understand:

FPS – Full Payment Submission
EPS – Employer Payment Summary

Here’s how they work.

1. FPS (Full Payment Submission)

The FPS is the most important RTI submission.

You must send an FPS on or before each payday, including:

Pay date
Gross pay
Tax deducted
Employee National Insurance
Employer National Insurance
Student loans/postgraduate loans
Statutory payments (SSP, SMP, SPP, SAP, ShPP)
Starter or leaver details
Tax codes
Hours worked (A–D bands)
Any adjustments affecting PAYE/NIC

When do you send the FPS?

Every single pay period — monthly, weekly or otherwise.

What happens if you send it late?

HMRC may apply late filing penalties unless there is a reasonable excuse.

2. EPS (Employer Payment Summary)

The EPS is used when there is something to report that wasn’t included in the FPS.

Examples include:

Recovering statutory payments (e.g., SMP reclaim)
No payments made in a period
Claiming Employment Allowance
CIS deductions suffered (for construction businesses)
Apprenticeship Levy adjustments
NIC holiday schemes (when applicable)

When do you send the EPS?

Usually after the FPS, but always by the 19th of the following month for it to affect PAYE owed that month.

Other RTI Submissions (Less Frequent)

These include:

Earlier Year Updates (EYUs) – used historically to fix prior year errors (now replaced by corrected FPS/EPS)
Final FPS of the year – includes the “final submission” indicator
P11D(b) – not technically RTI, but part of the wider reporting requirements

Modern payroll systems handle most of these automatically.

Employer Responsibilities Under RTI

As an employer, you must:

Send an FPS on or before payday
Submit EPS forms when required
Keep accurate payroll records
Apply the correct tax codes
Correct errors promptly
Pay PAYE/NIC to HMRC on time
Issue payslips, P45s and P60s correctly

Outsourcing payroll does not remove these obligations — but it greatly reduces the risk of errors or late submissions.

Common RTI Mistakes

Employers often encounter issues with:

Late FPS submissions

Usually caused by missing deadlines, missing data, or payroll being run too late.

Incorrect employee details

Wrong NI numbers, dates of birth or start dates cause downstream issues.

Not submitting an EPS when required

This can mean you pay too much PAYE or miss recoveries.

Wrong pay dates

RTI must use the actual contractual pay date — not the date you process payroll.

Incorrect handling of starters and leavers

Missing P45 details or failing to report a leaving date can cause incorrect tax.

Not correcting errors properly

HMRC requires corrected FPS/EPS submissions — not manual adjustments.

What Happens If You File RTI Late?

HMRC may issue:

Late filing penalties
Interest on late-paid PAYE
Compliance checks
Requests for explanation
Penalties for repeated failures

Consistent lateness can signal poor payroll controls.

How We Help Employers with RTI Compliance

Your Payroll Team can support you with:

RTI submissions (FPS & EPS)
PAYE and NI accuracy checks
Correcting historic RTI issues
Handling HMRC queries
Ensuring compliance during system changes or staff sickness
Full outsourced payroll services

Talk to a Payroll Specialist About RTI

FAQ: RTI Explained

Do I have to send an FPS even if no one is paid?
If no employees are paid in a period, you submit an EPS instead to inform HMRC.

Can RTI be corrected?
Yes — using a corrected FPS or EPS. You do not need to wait for the next year.

What happens if I miss the deadline?
You may receive a penalty. HMRC sometimes shows leniency for first offences.

Is RTI the same as PAYE?
No. PAYE is the system that collects tax/NIC. RTI is how you report that information.

What Is RTI? (FPS & EPS Explained for Employers)