Why percent complete matters so much
Percent complete isn't just a status update. It feeds three things that affect your money directly:
- Progress billing. How much you can invoice this period.
- [Earned value](/earned-value-for-contractors). The "value earned" figure that tells you if you're ahead or behind.
- [WIP reporting](/wip-report-for-small-gcs). Whether you're over- or under-billed.
Get percent complete wrong and you can over-bill (angering clients and inviting clawbacks) or under-bill (starving your own cash flow). It's worth measuring properly.
The four common methods
1. Cost-to-cost
The most widely used method: percent complete = costs incurred to date / total estimated costs. If you've spent $60,000 of a $100,000 budget, you're 60% complete.
- Best for: jobs where cost tracks closely with progress.
- Watch out: front-loaded costs (buying all your materials on day one) can make you look further along than you are. A pile of unused lumber on site isn't progress.
2. Units-of-work (physical units)
Measure progress by countable output: 800 of 1,000 square feet of flooring laid = 80% complete.
- Best for: repetitive, measurable work like flooring, drywall, roofing, painting.
- Watch out: doesn't fit lumpy, non-uniform work well.
3. Milestones
Assign a percentage to defined milestones. Rough-in complete = 30%, insulation and drywall = 60%, and so on.
- Best for: phased work with clear checkpoints, and progress-billing schedules tied to milestones.
- Watch out: you jump in steps, so you can sit at "30%" for a while, then leap. It's less granular.
4. Physical estimate (expert judgment)
The person running the job simply assesses how complete the work is and calls it. "Framing's about 75% there."
- Best for: complex or one-off work where no formula fits, and as a sanity check on the other methods.
- Watch out: it's subjective. Use it to check a formula-based number, not as your only method.
Which method should you use?
Match the method to the work, not the other way around:
- Uniform, countable work → units-of-work.
- Cost tracks progress well → cost-to-cost.
- Clear phases and milestone billing → milestones.
- Messy, one-off, or as a gut check → physical estimate.
Many contractors use different methods for different trades on the same job: units for flooring, milestones for the overall schedule. That's fine, as long as you're consistent within each.
The honesty test
Whatever method you pick, apply one rule: percent complete should reflect work actually installed, not money spent or materials delivered. The fastest way to fool yourself is to count a driveway of materials as progress. When cost-to-cost and physical judgment disagree sharply, trust your eyes and dig into why.
For sound cost baselines behind these percentages, keep your estimates realistic against the Construction Price Index.
Where this fits
Percent complete is the input that makes earned value tracking work, and it flows straight into WIP reporting and honest construction project management.
Put it to work
TradesMetrics tracks percent complete against the estimate you build in the free estimating tool, so your progress, billing, and margin stay in sync automatically. See how it works.