Use the calculator below for both sides of a job, and the job cash flow calculator to see retention alongside every other payment.
Retention calculator
How does retention affect my cash flow?
Retention your client holds is your money you cannot use until it is released. Retention you hold from your subcontractors offsets some of it. The difference is your own cash tied up in the job until the releases come.
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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See it on a quote
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