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UK Corporation Tax · FY2024 – FY2026

Corporation Tax Calculator

A practitioner-grade UK Corporation Tax calculator with marginal relief, associated companies, and accounting-period proration — plus a branded PDF for the client file.

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Maintained for current and recent UK tax years
Sample calculation
Taxable profit
£180,000
Associated companies
0
Band
Marginal relief
CT due
£43,950
Main rate £45,000 less marginal relief £1,050 (3/200 × (£250,000 − £180,000)).

See it in 20 seconds

Rates, marginal relief, associated companies, accounting periods, and a branded PDF — all in one short tour.

Everything a UK CT calculation needs

Built around the rules accountants actually apply at the year-end.

19% / 25% with marginal relief

Small profits rate, main rate and the 3/200 marginal relief band — applied automatically.

Associated companies

Divides the £50k / £250k thresholds by the number of associated companies plus one.

Short or long accounting periods

Pro-rates the thresholds by days in the period so off-cycle year-ends still calculate correctly.

Branded PDF exports

Hand the client a polished report with your firm's logo, the inputs used, and the full breakdown.

What you can model

Common adjustments and reliefs handled inside the same screen.

A quick tour

Three short steps from profits to a client-ready Corporation Tax report.

Step 1

Enter the company figures

Start with the accounting period, taxable profits and associated companies so the thresholds are set correctly from the outset.

  • Accounting period dates
  • Taxable profits input
  • Associated companies adjustment
  • Clean practitioner-style input panel
Corporation Tax input screen with accounting period, taxable profits and associated companies.
Step 2

See marginal relief live

The calculator shows where the company sits between the lower and upper limits and updates the effective rate instantly.

  • Lower and upper threshold markers
  • Effective rate shown clearly
  • Marginal rate surfaced separately
  • Tax due visible alongside the slider
Marginal Relief screen showing thresholds, effective rate, marginal rate and tax due.
Step 3

Review the answer and export

Finish with a clear breakdown of the rate calculation and export a branded PDF for the client file.

  • Corporation tax due headline
  • Main rate and marginal relief lines
  • Total shown clearly
  • One-click PDF export
Corporation Tax results screen with total tax due, breakdown table and export button.

Ready to run your first CT calculation?

The Corporation Tax Calculator is included in every NRD Calculators plan — alongside the rest of the library.

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Frequently asked questions

Quick answers on rates, rules and what's included.