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Plain-English guides to UK Corporation Tax and CT600 filing.

3 results for “associated companies”Clear search
21 February 2026

Small Company Corporation Tax Rates 2025/2026: Complete Guide

Understand corporation tax rates for small companies in 2025/2026, including the 19% and 25% thresholds, marginal relief calculation, and associated companies rules.

corporation tax ratessmall company2025/2026marginal reliefCT600
20 February 2026

Corporation Tax Calculator: How Much Will Your Company Pay in 2025/26?

Free corporation tax calculator. Understand the 19% and 25% rates, marginal relief, and how associated companies affect your bill.

corporation taxcalculatortax ratesmarginal relief
20 February 2026

Associated Companies — How They Affect Your Corporation Tax Rate

How associated companies change your Corporation Tax thresholds. What counts, what doesn't, dormant company exemption, and how to report them on your CT600.

associated companiescorporation taxthresholdsmarginal reliefCT600tax rate