Retainage calculator
Enter the contract amount, how far along the job is, and the retainage percent. The calculator writes out each step of the arithmetic with your numbers, including a rate that drops after a completion threshold and stored materials held at their own rate.
Your numbers stay on this device. Nothing is uploaded.
How the retainage is calculated
Result
For a job billed over several periods, with releases, use the retainage tracker. For the caps written into state statutes, see state retainage limits.
What gets checked
- Every step (work billed, the threshold amount, retainage at each rate) is worked a second time with separate whole-number arithmetic, and both results must agree to the cent.
- Work billed up to the threshold plus work billed after it adds back to the work billed.
- Retainage withheld plus net payable equals the gross amount billed.
- Retainage withheld is not more than the gross amount billed.
- A warning, not a failure, when work billed is more than the contract amount or the rate after the threshold is higher than the rate before it.
How it works
- Enter the contract and the progress. Type the contract amount, then either the percent complete or the amount billed to date. With a percent, work billed is the contract amount times the percent.
- Enter the retainage percent. With one rate and no threshold, retainage is that rate times the work billed to date.
- Add a threshold if the rate drops. Tick the box and enter the threshold as a percent of the contract and the rate after it. Work billed up to the threshold amount is held at the first rate; only work billed after it is held at the reduced rate.
- Add stored materials if billed. Stored materials are held at their own rate and are added to the gross amount billed. They do not count toward the threshold.
- Read the steps and the certificate. Each step is listed in order with the arithmetic written out, followed by retainage withheld, net payable, and the list of checks. Export to Excel or CSV, or print.
Worked example
A made-up $184,650.00 subcontract that is 62.5% complete. Retainage is 10% and drops to 5% on work billed after the job passes 50%. The invoice also carries $6,400.00 of stored materials held at 10%.
| Step | With these numbers | Result |
|---|---|---|
| 1. Work billed to date | $184,650.00 × 62.50% | $115,406.25 |
| 2. Threshold amount | $184,650.00 × 50.00% | $92,325.00 |
| 3. Work billed up to the threshold | the lesser of $115,406.25 and $92,325.00 | $92,325.00 |
| 4. Work billed after the threshold | $115,406.25 − $92,325.00 | $23,081.25 |
| 5. Retainage at 10% up to the threshold | $92,325.00 × 10.00% | $9,232.50 |
| 6. Retainage at 5% after the threshold | $23,081.25 × 5.00% | $1,154.06 |
| 7. Retainage on stored materials | $6,400.00 × 10.00% | $640.00 |
| 8. Retainage withheld | $9,232.50 + $1,154.06 + $640.00 | $11,026.56 |
| 9. Gross amount billed | $115,406.25 + $6,400.00 | $121,806.25 |
| 10. Net payable after retainage | $121,806.25 − $11,026.56 | $110,779.69 |
Retainage withheld is $11,026.56 and net payable is $110,779.69, which together make the $121,806.25 billed. Step 6 works out to $1,154.0625 and is rounded to $1,154.06.
The example uses made-up names and numbers.
Questions
How do you calculate retainage?
Multiply the work billed to date by the retainage percent. On a $50,000.00 contract with $12,345.67 billed and 10% retainage, retainage withheld is $1,234.57 and net payable is $11,111.10. The calculator writes this out with whatever numbers are entered.
What exactly happens at the threshold?
The threshold amount is the contract amount times the threshold percent. Work billed up to that amount stays at the first rate. Only work billed after it gets the reduced rate. Retainage already held on the earlier work is not recalculated or released by this calculator.
My contract lowers the rate on everything once the job passes the threshold. Does this do that?
No. This page applies the reduced rate only to work billed after the threshold, and says so beside the result. A contract can be written differently; the calculator reads no contract.
How is rounding done?
Each multiplication is rounded once to the nearest cent, and exactly half a cent rounds away from zero. Totals are sums of the rounded amounts.
How is this different from the retainage tracker?
This page works one invoice from the contract amount and progress to date and shows the steps. The retainage tracker keeps a running balance across many billing periods, with releases and a release invoice.
This tool calculates and checks numbers. It is not legal, tax, or medical advice.