Bespoke, never off the shelfUnlimited users, never per-seat30+ modules, one account14-day trial, no cardQR clock-in, timed at the scanPriced to your firmCyber Essentials PlusFree migration includedCDM 2015 built inUK hosted, UK supportInsurance expiry checked nightlyAndroid and iOS appNo minimums, cancel any timeBuilt to your processBookkeeping capture, by email99.97% uptimeExport everything, any time
Book a demo→
Free tool

What is being held,
and when you get it back.

Retention is easy to calculate and easy to lose, and firms lose it on the dates rather than the arithmetic. Set the job with the sliders, put in your practical completion date, and both halves come back with the day each falls due. Nothing is sent anywhere.

01The job

Worked out in your browser as you move the sliders. No job figures are sent to Unibuild, stored, or logged.

Retention held £12,5005% of £250,000 certified5% held
From practical completion to release
Today
Practical completion 5 April 2026 £6,250 released
Defects period ends 5 April 2027 £6,250 falls due
  1. First release£6,250.0050% of the retention held, due on practical completion, subject to your contract.
  2. Second release£6,250.00The balance, 12 months after practical completion. This is the half most often uncollected.

On many contracts the second half is due on a making good certificate rather than on the date alone. Where that is yours, the second date is when to start asking for the certificate, not when the money arrives.

Why the second half goes uncollected When it actually falls due
Past the diary

Hold the dates
on the job.

A release date in somebody’s diary leaves when they do. Held against the job, the second moiety is still there in a year, when the file is closed and the person who ran it has moved on.

Book a 30-minute demo

Prefer to talk first? +44 7587 557546 or email us.

Ask for a quote

A tailored quote
for your firm.

One flat monthly figure that covers everything, sized to your firm once. Never per seat, fixed for three years, and usually answered the same working day.

Headcount
Areas of interest

Your enquiry carries the page you came from, so we know which of these you were working on. Privacy policy.

The dates

The sum is
the easy part.

Why the second release is the one that goes missing, when release is conditional rather than automatic, and what this tool deliberately does not model.

A worked example

Take a subcontract with a certified value of £250,000 and retention at the common rate of 5 per cent. The employer holds £12,500.

Half of that, £6,250, falls due on practical completion. Say practical completion is certified on 13 March 2026. With a twelve-month defects liability period, the second half, another £6,250, falls due on 13 March 2027.

The arithmetic took a moment. The second date is a year away, and it is the one that decides whether the money comes back. On a firm turning over £3m with 5 per cent held across its jobs, the second moiety sitting uncollected is a five-figure sum that nobody has written off and nobody is chasing.

The second date is the one that costs money

The first release you will chase, because you finished last month and the job is fresh. The second falls due a year or more later, when the job is closed, the file is archived and the person who ran it has often left. That is where retention goes missing, and it goes missing to ordinary forgetfulness rather than to anybody refusing to pay.

Which is why this tool returns dates rather than only sums. Put the second date somewhere that will still be looked at in a year, and you have done the single thing that determines whether you collect it.

Release is often conditional, not automatic

One thing this calculator cannot know: on many contracts the second half is not due at the end of the defects period at all. It is due on the issue of a making good certificate, or its equivalent, which somebody has to actually produce.

If that is your contract, the second date is when to start asking for the certificate rather than when the money arrives. The distinction matters, because until the certificate is issued the payment is not late in any contractual sense and never becomes so.

What this does not model

It handles the ordinary case: a percentage of certified value, released in two parts, the second at the end of a defects period running from practical completion. It does not model capped retention, stepped or phased release, or retention bonds substituting for cash. Nor does it model contracts where your release is tied to the main contract's practical completion rather than your own. That last one is common on subcontracts and can push the money months beyond anything in your control.

All of those are worth knowing about before you sign rather than after, and they are covered in retention, and the money that goes missing after practical completion.

Practical completion

The second half goes missing to forgetting, not to refusal.

A year later
Asked most often

Retention, in plain terms.

Short answers. The contract wins over all of them, so read it where the two disagree.

How is retention calculated in construction?
Multiply the certified value of the work by the retention percentage in the contract. On £250,000 at 5 per cent the employer holds £12,500. Retention is normally deducted from each interim payment as the value certified grows, so it accumulates over the job rather than being taken in one go at the end. It is held against the whole certified value, not against a single application.
What is a normal retention percentage in UK construction?
Three per cent and five per cent are both common. Five is the figure most subcontracts still use, and three is increasingly seen on larger contracts. There is no statutory rate and no statutory cap, so the only percentage that matters is the one written into your contract. Some contracts also cap retention at a fixed sum once the value passes a threshold, which a percentage on its own will not tell you.
When is retention released?
In two parts on most contracts. The first half falls due at practical completion. The second half falls due at the end of the defects liability period, which typically runs six or twelve months from practical completion. On many contracts the second half is conditional on a making good certificate being issued rather than on the date alone. The date is then when to start asking, not when the money arrives.
What is the defects liability period?
The period after practical completion during which you remain responsible for putting right defects in your own work. Six and twelve months are the usual lengths. It is also the period the second half of retention is held against, which is why its end date and the retention release date are normally the same day.
What does moiety mean in a retention clause?
A half. The first moiety is the half released at practical completion and the second moiety is the half released at the end of the defects liability period. It is old contract language rather than a term of art, and it means nothing more than half.
What if the client never releases the retention?
Retention is a payment like any other under the Housing Grants, Construction and Regeneration Act 1996, so the payment notice and pay less notice machinery applies to it. If it has fallen due and no valid pay less notice was served, the sum is payable in full on the final date for payment. Work out those dates on the payment timetable calculator. In practice most unpaid retention is not refused, it is forgotten by both sides. That is why the release dates are worth recording on the job when the contract is signed.
Next step

Hold the dates on the job, not in a diary.

Book a 30-minute demo → Ask for a quote
Phone · UK hours
+44 7587 557546
Email
success@unibuild.co.uk
The module
Applications for payment
The other tool
Payment timetable calculator