On a £100,000 contract with 5% retention, £5,000 is held. Half, £2,500, comes back at practical completion on Monday 30 November 2026, and the rest, £2,500, at the end of a twelve month defects period on Tuesday 30 November 2027.
Retention calculator
How is retention calculated in construction?
In UK construction, retention is set by the contract, not by law. Multiply the contract value, or each payment, by the retention rate in the contract. That is what the client holds back. Part is usually released at practical completion and the rest at the end of the defects period.
Free, with no sign-up. Everything is worked out in your browser: nothing you type is sent to us or stored. Retention terms come from your contract. This works out the figures and dates from the terms you enter.
Retention held, and when it comes back
Both sides of a job: what your client holds from you, and what you hold from your subcontractors.
- Your cash tied up in retention
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Sources
The rates, thresholds and dates on this page come from these official sources, read on 31 October 2026.
Where SUBR comes in
SUBR is AI software for UK contractors who send work out to subcontractors. Its AI reads your client quote, your office names each trade's share, and SUBR builds every scope with your costs, margin and client price left off it. Each subcontractor answers on their own link and sees only their own price.
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