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How to calculate retainage in construction

6 min read · Updated June 2026

Retainage (also called retention) is a percentage of each progress payment that the owner or general contractor holds back until the job is complete, as security that the work will be finished correctly. On a pay application it reduces what you collect now — so understanding the math keeps your cash flow predictable.

What retainage is

Each billing period, a set percentage of the work you have earned is withheld and accumulated. It is released near the end of the job. The most common rates are 5% and 10%. Some contracts withhold 10% until the project is 50% complete, then stop withholding on the remaining work.

How to calculate retainage

The formula is simple: retainage = retainage rate × amount completed and stored to date. Two things matter:

  • It is calculated on the cumulativecompleted-and-stored amount (G703 column G), not just this period's work.
  • On the G702 it appears on Line 5: 5a is retainage on completed work, 5b is retainage on stored materials. The total is subtracted on Line 6.

A worked example

Take a single $10,000 line item with 10% retainage, billed across three periods.

App% completeCompleted to dateRetainage (10%)Earned less retainagePaid this period
140%$4,000$400$3,600$3,600
270%$7,000$700$6,300$2,700
3100%$10,000$1,000$9,000$2,700

After the third application you have been paid $9,000, and $1,000 of retainage is still being held — that is released with your final payment once the job closes out.

Completed work vs stored materials (5a vs 5b)

Line 5a is retainage on work you have actually installed. Line 5b is retainage on materials delivered to the site but not yet installed. Whether retainage applies to stored materials is a contract question — check before you assume.

When you get retainage back

Retainage is released at substantial or final completion, usually after the punch list is done and you have submitted any required lien waivers. If your contract uses a 50% reduction, withholding stops on work billed after the halfway point.

Watch the contract and your state

The rate, any reduction threshold, and whether retainage applies to stored materials are all set by your contract. Many states also cap retainage on public projects and set release timelines under prompt-payment or retainage statutes — confirm the rules for your specific project.

Stop building pay apps in a spreadsheet

DrawFort fills in the carry-forward, computes retainage and current payment due, handles change orders, and exports a clean G702/G703 PDF your GC can approve at a glance.

Frequently asked questions

What is a normal retainage percentage?

5% and 10% are the most common. Some contracts hold 10% until the job is 50% complete, then stop withholding on the remaining work — sometimes called reduced retainage.

Is retainage calculated on each payment or the running total?

On the cumulative amount completed and stored to date. On the G702 it appears as Line 5 and is subtracted from Line 4 (total completed and stored) to get total earned less retainage.

Do I withhold retainage on stored materials?

Sometimes. Line 5b on the G702 covers retainage on materials presently stored, but whether it applies depends on your contract — some hold retainage on stored materials and some do not.

When is retainage released?

Typically at substantial or final completion, after the punch list is finished and required lien waivers are submitted. Final payment includes the accumulated retainage.

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