What are the UK corporation tax rates for 2025/26?

Profits up to £50,000: 19% (small profits rate). Profits from £50,001 to £249,999: marginal relief applies between 19% and 25%. Profits of £250,000 and above: 25% (main rate). These thresholds are divided by one plus the number of associated companies.

What are associated companies for QIP threshold purposes?

Associated companies include other companies under common control. If company A and company B are both controlled by the same person or group, they are associated. The large company threshold (£1.5 million) and very large threshold (£20 million) are each divided by one plus the number of associated companies.

Can a company elect out of the QIP regime?

There is no general election to opt out of QIPs once the large company threshold is met. However, if profits fall below the threshold in a later period, the company reverts to normal payment. Professional tax advice is important for companies near the threshold.

Corporation Tax Quarterly Instalment Calculator 2025/26

Q: What are the QIP due dates for standard large companies?

For a standard 12-month accounting period, the four instalments are due in months 7, 10, 13, and 16 from the start of the accounting period. In practice, the first two are paid during the accounting period (months 7 and 10), and the last two are paid after the period ends (months 1 and 4 of the following period).

Q: How is marginal relief calculated for corporation tax?

Marginal relief reduces the corporation tax liability for profits between £50,000 and £250,000. The formula is: (Upper limit - Profits) / (Upper limit - Lower limit) × Standard fraction × Profits. For 2025/26 the standard fraction is 3/200. This gives an effective marginal rate of 26.5% on profits between £50,000 and £250,000.

Q: When is the normal corporation tax payment deadline?

Companies not required to pay QIPs pay the full corporation tax liability 9 months and 1 day after the end of the accounting period. For example, a 31 March 2025 year-end means payment is due by 1 January 2026.

Calculate Your QIPs Payment Schedule

Accounting period start date

Accounting period end date

Estimated taxable profits (£)

Number of associated companies

Prior year augmented profits (£) — for QIP eligibility check

QIPs required?

Company type

Adjusted large company threshold

Estimated CT rate

Estimated CT liability

Each instalment (25% of liability)

Instalment 1 due date

Instalment 2 due date

Instalment 3 due date

Instalment 4 due date

Alternative: single payment date (if not QIPs)

Assumes a 12-month accounting period. Dates calculated are 14th of the relevant month. QIPs thresholds divided by (1 + number of associated companies). Seek professional advice for accuracy.

Who Must Pay Corporation Tax in Quarterly Instalments?

The QIP regime requires large companies to pay corporation tax earlier than the standard 9 months and 1 day after the accounting period end. A company is large for QIP purposes when its augmented profits exceed £1,500,000, adjusted downward if it has associated companies.

The threshold is divided by (1 + number of associated companies). For a company with two associates, the effective threshold is £1,500,000 ÷ 3 = £500,000. This means medium-sized companies in groups may be caught much earlier than their standalone profits would suggest.

Standard Large Company QIP Dates

Instalment	Due (months from AP start)	Example (1 Apr 2024 start)
1st instalment	Month 7 (14th)	14 October 2024
2nd instalment	Month 10 (14th)	14 January 2025
3rd instalment	Month 13 (14th)	14 April 2025
4th instalment	Month 16 (14th)	14 July 2025

Very Large Company QIP Dates (Profits > £20 million)

Instalment	Due (months from AP start)	Example (1 Apr 2024 start)
1st instalment	Month 3 (14th)	14 June 2024
2nd instalment	Month 6 (14th)	14 September 2024
3rd instalment	Month 9 (14th)	14 December 2024
4th instalment	Month 12 (14th)	14 March 2025

Corporation Tax Rates 2025/26

Profits	Rate	Notes
Up to £50,000	19%	Small profits rate — thresholds ÷ (1 + associates)
£50,001 to £249,999	19% to 25% (marginal)	Effective marginal rate 26.5%
£250,000 and above	25%	Main rate — thresholds ÷ (1 + associates)

Frequently Asked Questions

What are Quarterly Instalment Payments (QIPs)? +

QIPs are a system requiring large UK companies to pay corporation tax in advance of the normal 9-month-plus-one-day payment deadline. Large companies (augmented profits over £1.5 million, adjusted for associated companies) must pay in four quarterly instalments.

Which companies must pay QIPs? +

A company must pay QIPs if its augmented profits exceed £1,500,000 divided by one plus the number of associated companies. Companies in their first year of being large may qualify for the new large exemption and pay as normal.

What are the QIP due dates for standard large companies? +

For a standard 12-month period, instalments are due in months 7, 10, 13, and 16 from the start of the accounting period (on the 14th of each month). The first two fall within the accounting period; the last two fall after it ends.

What are UK corporation tax rates for 2025/26? +

Profits up to £50,000: 19% (small profits rate). Profits from £50,001 to £249,999: marginal relief applies (effective marginal rate 26.5%). Profits of £250,000 and above: 25% (main rate). These thresholds are divided by one plus associated companies.

What is the 'new large' company exemption? +

A company that was not large in the immediately preceding accounting period is not required to pay QIPs in its first year of being large. It pays the liability as a single payment. QIPs are required from the second consecutive year of being large.

How does HMRC charge interest on late QIP payments? +

HMRC charges late payment interest on overdue QIPs from the due date at Bank of England base rate plus 2.5%. Repayment interest is also paid by HMRC on overpayments from the date of overpayment.

What are associated companies for QIP purposes? +

Associated companies include other companies under common control. The large company threshold (£1.5m) and very large threshold (£20m) are each divided by one plus the number of associated companies, reducing the effective threshold for each company in a group.

What happens if QIP estimates turn out to be wrong? +

QIPs are based on estimated profits. If actual profits are higher, HMRC charges interest on the underpayment from the original due date. If actual profits are lower than estimates, HMRC pays repayment interest on the excess. Revising estimates each quarter is good practice.

How is marginal relief calculated for corporation tax? +

Marginal relief applies between £50,000 and £250,000 profits. The formula uses the standard fraction 3/200: marginal relief = (£250,000 - profits) ÷ £200,000 × 3 × profits / profits (simplified to standard fraction × (upper limit - profits)). The effective marginal rate is 26.5%.

When is the normal corporation tax payment deadline? +

Companies not required to pay QIPs pay the full CT liability 9 months and 1 day after the end of the accounting period. For example, a 31 March 2025 year-end means payment is due by 1 January 2026.

What is a very large company for QIP purposes? +

A very large company has augmented profits exceeding £20,000,000 (divided by one plus associated companies). Very large companies pay instalments in months 3, 6, 9, and 12 of the accounting period — all within the current year, giving far less time to estimate profits.

Can I reduce QIPs if I revise my profit estimate downward? +

Yes. Each QIP is based on your best estimate at the time. If profits decrease, you can reduce later instalments to reflect the lower expected liability. HMRC will calculate interest based on the correct liability once the actual return is filed.