TOOLS
Standalone tools. Numbers, not opinion.
Four single-purpose calculators outside the loan flow. Each runs entirely in the browser, sources its rates from current HMRC guidance, and links back to the underlying reference material on this site.
PAYE PENALTY
PAYE arrears penalty estimator
Penalty band, late-payment interest, and total HMRC cost on a PAYE bill paid late. Bands scale with prior defaults in the tax year.
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MTD POINTS
MTD penalty points checker
How close you are to the £200 fixed penalty under the points-based late submission regime. Phase 1 grace period flagged.
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R&D CLAIM
R&D claim sizer
Estimate the cash value of an SME or RDEC R&D claim. Current 2025 to 2026 rates, with subcontractor restriction applied.
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DIRECTOR S455
Director's loan s455 calculator
The 33.75% s455 charge on overdrawn director loans not repaid within nine months and one day, plus beneficial loan interest.
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Tools vs calculators
Why two sections.
Calculators sit alongside the loan flow: VAT loan repayment, penalty vs loan, daily HMRC interest. Tools live outside it: estimators for tax events that don't always end in a loan. Both are free. Both update with the rate engine on the front page.