Irish PRSI — methodology

Plain-English summary

PRSI (Pay Related Social Insurance) is the Irish social-insurance contribution funded jointly by employees and employers. It pays for things like Jobseeker's Benefit, Illness Benefit, Maternity Benefit, and the State Pension (Contributory). Your PRSI is determined by your PRSI Class, which is set by the Department of Social Protection based on your employment type.

Most employees in private-sector jobs are in Class A. Inside Class A, the subclass (A0, AX, AL, A1) is what the payroll system actually uses week-to-week, and the subclass depends on your weekly earnings band. The two big things to understand are the threshold structure (the cliff edges where rates change) and the PRSI credit, which softens the jump between sub-thresholds and full Class A1 contributions.

PayslipIQ recomputes the PRSI for the payslip's earnings, class, and pay date. We also model the PRSI credit taper between €352 and €424 per week, and we flag the 4.2% to 4.35% rate change effective on 1 October 2026.

Data inputs accepted

• PRSI class and subclass as printed on the payslip
• Pay frequency (weekly, fortnightly, monthly)
• Gross PRSIable pay for the period
• Pay date (to select the correct rate set, including the 1 Oct 2026 cutover)
• Insurable weeks for the period

Class A subclasses

Step-by-step calculation logic

1. Convert pay to a weekly equivalent. Monthly pay ÷ 4.333; fortnightly ÷ 2. Subclass is determined on the weekly figure.
2. Determine the subclass. Apply the bands above to the weekly equivalent.
3. Pick the correct rate effective on the pay date. Before 1 Oct 2026, employee Class A full rate is 4.2%; on or after that date it is 4.35%.
4. Apply the PRSI credit. For weekly earnings between €352.01 and €424.00, deduct a tapered credit from the calculated PRSI. Credit starts at €12.00 (for €352.01) and tapers by €1 for every €6 above €352.01, reaching €0.00 at €424.00.
5. Compute employer PRSI. Apply the relevant employer rate to gross PRSIable pay.
6. Reconcile. Compare against the slip; any difference greater than €0.50 is surfaced as "needs confirmation".

Worked example

Aoife is weekly-paid Class A. Her 9 October 2026 payslip shows gross weekly pay of €380.00.

• Weekly equivalent: €380.00 → subclass AX
• Pay date is after 1 October 2026 → employee rate 4.35%
• Gross PRSI: €380.00 × 4.35% = €16.53
• PRSI credit: €380.00 is €27.99 above €352.01 → credit of €12.00 − floor((€27.99/€6)) × €1 = €12.00 − €4.00 = €8.00
• Net employee PRSI: €16.53 − €8.00 = €8.53

We compare against the slip. Variances of more than €0.50 are flagged with the worked figures so Aoife can ask payroll to clarify.

Edge cases handled

• Pay date straddles 1 Oct 2026 — we use the pay date, not the period worked, to pick the rate (per Revenue practice).
• Multiple insurable weeks in one pay period — we recompute on a weekly basis and aggregate.
• Class S directors — minimum annual contribution applies; we flag potential under-collection.
• Class K — applies to certain unearned income and public-office holders; rates differ.
• Below €38/week — Class J applies (employer-only at low rate); we surface a class-mismatch note if A is shown.
• Holiday pay paid in advance — usually treated as weekly equivalents on the underlying weeks; we follow the slip's stated insurable weeks.

Limitations and known gaps

• Public-service classes (B, C, D, H) are not modelled in this engine.
• BIK PRSI exposure on share schemes is approximated only when explicitly itemised.
• The 1 Oct 2026 step-up uses pay date; legacy payroll systems sometimes lag — we flag rather than override.
• PRSI credit taper rounds to the nearest cent; small variances against payroll engines are tolerated.

Sources used

Disclaimer

PayslipIQ provides informational analysis only. We do not provide tax, legal, or employment advice. PRSI class is set by the Department of Social Protection based on information your employer files; if you believe your class is wrong, contact your employer or your local Intreo Centre.