The docket · Free UK tools

Compliance & Property Calculators

Quick, no-signup tools for UK contractors, landlords and small businesses — built to match current HMRC rates and statutory rules, checked regularly.

Construction · CIS340

CIS Deduction Calculator

Work out the 20%, 30% or gross-status deduction on a subcontractor's invoice — labour only, materials excluded.

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Construction · Self Assessment

CIS Refund Estimator

Estimate your Self Assessment refund by comparing CIS deducted against tax and NI actually due.

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Construction · Contract terms

Retention Calculator

Work out retention withheld on a contract, split between practical completion and defects liability release.

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Debt recovery · LPA 1998

Late Payment Interest Calculator

Calculate statutory interest and fixed compensation owed on an overdue B2B invoice under UK law.

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Landlord costs · 2026 rates

Letting Agent Fee Calculator

See the real annual cost of full management, rent collection or tenant-find — including VAT.

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About these tools. Every calculator here is built for guidance, not formal advice — rates and thresholds are checked against current HMRC and statutory guidance, but always confirm figures for anything you're submitting or invoicing on against the original source (HMRC, legislation.gov.uk, or your accountant) before relying on them.