Business
Preliminary Corporation Tax Calculator Ireland
Compare normal small-company and large-company instalment targets. This free preliminary corporation tax calculator ireland shows the calculation and its assumptions so you can compare your own figures.
Your results
Compare normal small-company and large-company instalment targets.
Calculated outcomes
- First Instalment Target
- €50,000.00
- Company Size Class
- Small-company method
Assumptions and estimates
- Normal 12-month accounting period. Existing small-company test uses prior annualised CT not above €200,000; preliminary payment is lower of 100% prior or 90% current. First-period exemption uses Revenue's published below-€200,000 criterion; at or above that amount the model uses current-year liability, never a fictitious zero prior year. Normal large-company first instalment is lower of 50% prior or 45% current; a first period uses 45% current. The second instalment tops up to 90% current. Threshold/tax definitions differ for section 239 Income Tax and surcharges; short periods, credits, Pillar Two, group allocation and due dates require separate confirmation.
- Method: Small-company lower-of basis, qualifying first-period exemption, or large-company instalments bringing paid preliminary CT to 90% current liability.
- Rates/conditions reviewed against the linked official sources on 5 October 2026. Confirm the stated scope before relying on the result.
Sources: Official rules and guidance, Instalment amounts and due dates
Useful next steps
- Use Compare options to test an alternative side by side.
- Check the official sources above before relying on the figure.
- Copy, print or download a record of this calculation when you need one.
Reports open your email app addressed to s@s1.ie with the public page address only. Your inputs are never added.
How the preliminary corporation tax calculation works
Small-company lower-of basis, qualifying first-period exemption, or large-company instalments bringing paid preliminary CT to 90% current liability.
Rates/conditions reviewed against the linked official sources on 5 October 2026. Confirm the stated scope before relying on the result.
Using this calculator
- Enter your own figures in the labelled inputs. Keep the currencies, units and time periods consistent.
- Choose any applicable rate profile, pattern or assumption shown for this tool. Open additional inputs when relevant.
- Review preliminary cttarget and second instalment top up, then read the stated assumptions and eligibility conditions before using the result.
Official sources and further information
Worked example
This is a static example using illustrative inputs, not facts about you or today’s date. The displayed eligibility selections and assumptions apply only to this example.
See example inputs
- Estimated current CT liability (€)
- 60000
- Prior CT liability annualised to 12 months (€)
- 50000
- This is the first accounting period
- No
- Large-company first instalment actually paid (€)
- 0
- Preliminary CTTarget
- €50,000.00
- Second Instalment Top Up
- €0.00