You invoice 1,800 EUR. At the end of the month less is in the account than expected. Where did the money go? Post-calculation answers that — comparing planned costs with actual costs.

Most sign shops do no systematic post-calculation. Without feedback on your actual margin, you will quote the next similar job incorrectly again.

What post-calculation means

Comparison of the planned quote (what you costed in the estimate) with actual costs (what the job really cost). The difference is your real margin — or your loss.

The five most common margin killers

1. Extra work without a change order

Can you just quickly... — and you do it without charging. Every service beyond the original quote is a change order. Written confirmation, no exceptions.

2. Material waste not quoted

You quote 4m2 of film, use 5.2m2. Always include 15-25% waste allowance.

3. Installation time systematically too short

If you regularly find 30-50% more installation time in post-calculation: systematic problem. Use benchmarks from the installation time article and recalibrate.

4. Rectification work not booked

Return trip for rework costs 2h — does that land in post-calculation? Log every rectification with a timestamp against the job.

5. Bad debt not priced in

Bad debt typically costs 1-3% of annual revenue. Add a 2-3% risk premium. Require deposits from new clients.

Post-calculation step by step

Step 1: record actual material costs. Step 2: record actual labour time (including prep, installation, return trip, rectification). Step 3: other actual costs. Step 4: compare plan vs. actual.

Example: a job that looked fine and ended at 0% margin

Material film: plan 180 EUR, actual 224 EUR (+24%). Installation 5h x 80 EUR: plan 400 EUR, actual 560 EUR 7h (+40%). Travel: plan 24 EUR, actual 56 EUR (return trip). Cost total: plan 604 EUR, actual 840 EUR. Quote price: 840 EUR. Margin: plan 236 EUR (28%), actual 0 EUR (0%).

Margin vs. mark-up

25% mark-up on 100 EUR cost = sale price 125 EUR = margin only 20%. For a true 25% margin: cost divided by 0.75 = 133.33 EUR. Target for sign making: gross margin 35-45% (after material, before labour).

AI-powered post-calculation analysis

PlotonIQ automatically identifies patterns: which job types have systematically lower margins? Which clients cause disproportionate rework? Which months see installation time spike? These insights feed into future quotes. AI analysis

Conclusion

Without post-calculation you quote on assumptions that may never have been correct. In PlotonIQ it takes 10 minutes. Start free | Hourly rate guide | Sign making quoting guide