A construction retainage calculator for contractors and subcontractors. Turn your contract value, payment history, and days outstanding into a clear cash snapshot, a modeled release schedule, and a factual follow-up email.
Your project figures
Cash snapshot
Retainage withheld
Retainage still unpaid (modeled)
Earned but unpaid
Modeled cost per additional day
Modeled cost of another 30 days
Modeled carrying cost to date
Total modeled cash outstanding
The carrying-cost figures are only a user-supplied scenario. They do not establish a contractual interest rate, payment deadline, lien right, or entitlement.
If payment slips further
See modeled cash outstanding if the current delay lasts another 30, 60, or 90 days. These are planning scenarios, not interest claims.
Extra delay
Cash outstanding
Added carrying cost
When retainage typically releases
Modeled against a common reduction rule. Your contract controls whether retainage actually drops, and when.
Proper hold at this percent complete
Retainage withheld to date
Typically already releasable
Still held above the reduced rate
What bid keeps the same cash coming in?
Treat the contract value as the price you would accept with no retainage. The table shows 0%, 5%, 10%, and this worksheet’s rate. Bid to keep progress cash is what most contractors add before they sign: it recovers the withheld slice from progress payments. The economic add-on only covers modeled carrying cost of the hold — usually a few hundred dollars, not the cash-now gap.
Retainage
Withheld
Progress cash
Carry over hold
Bid to keep progress cash
Extra to add
100% retainage cannot be grossed up from progress payments. This is a planning model, not a reading of your subcontract or a claim that retainage is or is not lawful on this job.
Compare a partial retainage check
General contractors often offer a check today against retainage. That check can close the rest (a waiver or discounted payoff) or only accelerate part of it. Carrying cost here is applied only to the retainage still unpaid — the cash in the offer — not to other earned-but-unpaid progress. Should I take partial retainage now?
Path
Cash from retainage
Added carrying
Net after carrying
Vs waiting
This table does not tell you to accept, refuse, or sign. A waiver, change order, or lien release is a legal decision you review with your contract and counsel.
Private project report
Factual payment follow-up
Payment milestones
Optional private schedule for checking your worksheet against billed and paid amounts. Add rows as needed; blank rows are ignored.
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No warranty. This tool is provided free and as-is, without warranty of any kind, express or implied. It is not legal, tax, financial, or engineering advice, and it does not replace a qualified professional. You are responsible for reviewing and verifying its output before relying on it, and for meeting any obligation it helps you prepare for. To the maximum extent permitted by law, the authors accept no liability for any loss or damage arising from its use.
Best-effort hosting, no SLA. These tools are free, experimental, and may be slow, broken, moved, or taken offline without notice. We do not promise uptime, backups of anything you type, or that a URL will keep working. Do not use this as a system of record. If a tool needs to survive, export your inputs and run it yourself.
Free and open source. If it helped you plan around a slow retainage release, the code is under an MIT licence — GitHub Sponsors is optional and never changes what the tool does.
Planning the whole subcontract's payment timing — materials, retention, and late-payment buffer — rather than just the retainage hold? The subcontractor cash flow planner models the funding gap before you order, and the certificate of insurance tracker checks whether the subs you are holding retainage on are still insured — nothing uploaded.
Common questions
How much retainage will be withheld on my contract?
Retainage withheld is the contract value times your retainage percentage — it does not depend on how much has been paid to date. On the worksheet defaults, a $100,000 contract at 10% retainage withholds $10,000.00. The calculator separately tracks retainage still unpaid, which is capped at whichever is smaller: the full retainage withheld, or the earned-but-unpaid balance.
Is retainage the same thing as an unpaid invoice?
No. Earned but unpaid is the contract value minus what has actually been paid — $25,000.00 on the defaults ($100,000 contract, $75,000 paid). Retainage still unpaid is a narrower figure inside that: the smaller of the retainage withheld ($10,000.00) or the earned-but-unpaid amount. On the defaults the full $10,000.00 of retainage is still inside that $25,000.00 owed, not on top of it.
When does retainage typically release?
The calculator models a common AIA-style rule: the full retainage rate applies to billed work until the job passes a reduction point (50% complete by default), then the rate drops to a lower reduced rate (5% by default). On the worksheet defaults — a job 75% complete against that 50%-complete reduction point and 5% reduced rate — the modeled proper hold is $5,000.00 of the $7,500.00 progress retainage billed, meaning about $2,500.00 is typically already releasable. This is a planning model built from a common contract pattern, not a reading of your actual subcontract — check the release terms your contract actually states.
What does a payment delay actually cost me?
The calculator applies your own annual carrying-cost assumption only to the earned-but-unpaid balance, not the full contract value. On the defaults — $25,000.00 earned but unpaid at a 12% annual carrying-cost assumption — each additional day models about $8.22, and another 30 days of delay models about $246.58. Over the 90 days already outstanding in the default scenario, that comes to $739.73 in modeled carrying cost on top of the $25,000.00 owed. This is a planning figure using your own rate assumption, not a contractual interest claim.
Should I bid higher to cover retainage?
The calculator compares what it takes to keep the same progress-payment cash at 0%, 5%, and 10% retainage. On a $100,000 job at 10% retainage, keeping the same cash flow as a no-retainage job means bidding $111,111.11 — $11,111.11 more — because the withheld 10% has to be grossed back up from progress payments. That is different from the smaller economic add-on ($296.77 on the defaults) that only covers the modeled carrying cost of the hold. Most contractors price the cash-now gap, not just the interest, when retainage is negotiable.
Should I take a partial retainage check now?
On the worksheet defaults — a $100,000 contract with 10% retainage, $75,000 paid, and a 12% carrying-cost assumption — waiting 60 days for the remaining $10,000 models $197.26 more carrying cost on that retainage, leaving $9,802.74. A $5,000 check that closes the rest is $4,802.74 behind that wait. If the other $5,000 still arrives in 60 days, taking the check now leaves $9,901.37. The calculator shows the arithmetic; it does not tell you to sign a waiver.