Size the gallons, mark up the job to your target margin, and drop it straight onto a client invoice with tax.
Trades 6 min read
POST /tools/paint
{"length":14,"width":12,"height":9,"coats":2}paint returns gallons needed and coat count from room dimensions (accounts for openings and coverage).
Feed the material and labor cost into markup for a true selling price at your target margin, then drop the result straight onto a client invoice with invoice-generator — line items, discount, and tax all in one totaled document.
paint-job-quote chains paint → markup → invoice-generator for you. Need the tax broken out as its own line instead of baked into the invoice? sales-tax does that in isolation, tax-inclusive or tax-exclusive.