Methodology
Here is every formula, every source with its address and the day we read it, and the hand-verified cases. Nothing you see in a quote is a market price: they are your numbers.
The quote
- Labor by the hour = hours × workers × hourly rate.
- Labor by the square foot = area of the job × your price per square foot.
- Materials = whole units (cans, sheets, bags) × your price per unit.
- Subtotal = labor + materials.
- Overhead = subtotal × percentage.
- Profit = (subtotal + overhead) × percentage.
- Total = subtotal + overhead + profit.
Labor, materials, overhead and profit are rounded to the cent (half a cent up) and the total is the sum of the rounded lines. Material quantities are always rounded up to whole units.
The numbers the fields start with (8 hours, $25 an hour, 10% and 15%, the prices of paint, sheets and bags) are an example so the first quote reads; they are not prices or recommendations.
Materials
The quantities come from the Maestro Calc calculators, which explain their methodology at maestrocalc.com/methodology. We repeat them here with their sources.
- Paint: the four walls less 20 sq ft per door and 15 sq ft per window, at 350 sq ft per gallon per coat, the low end of the 350 to 400 in the Sherwin-Williams data sheet (July 2020). One-gallon cans, rounded up.
- Drywall: the area of the walls (and the ceiling if included) less doors and windows, with the waste you enter, over 32 sq ft (4 × 8 sheet) or 48 sq ft (4 × 12), rounded up.
- Concrete: length × width × thickness plus the waste, over what one bag makes: 0.30, 0.45 or 0.60 cu ft for 40, 60 and 80 lb, from the QUIKRETE No. 1101 data sheet (October 2022). Rounded up.
- Landscaping: length × width × depth plus the waste, over the volume printed on the bag (1.5, 2 or 3 cu ft), rounded up. Conversions use the exact factors of NIST SP 811.
- Cleaning: no quantity is worked out; the supplies are your figure.
Wages by state
The wage pages use the hourly mean and median wage of the May 2025 state estimates of the Occupational Employment and Wage Statistics (OEWS) survey of the U.S. Bureau of Labor Statistics (BLS). The occupations are 37-2012 maids and housekeeping cleaners, 47-2141 painters (construction and maintenance), 47-2081 drywall and ceiling tile installers, 47-2051 cement masons and concrete finishers, and 37-3011 landscaping and groundskeeping workers.
The numbers are fetched with the script apps/cobro/scripts/fetch-wages.ts from the BLS public API (version 1, series OEUS…03 for the hourly mean wage and OEUS…08 for the median) and stored without text. If BLS does not publish one of the two figures for a state and an occupation, that page does not exist.
A wage is what an employer pays an employee. It is not what a contractor bills: the rate also covers overhead and profit.
Hand-verified cases
Each case was worked out by hand with the formulas above. The automated tests run the same cases through the calculator and compare every figure, so this table cannot differ from what you see on the site.
| Case | Labor | Materials | Units | Total |
|---|---|---|---|---|
| Cleaning, starting values: 8 h, 1 person at $25, $20 of supplies, 10% and 15% | $200.00 | $20.00 | 0 | $278.30 |
| Cleaning, 3.5 h, 2 people at $18, $14.50 of supplies, no markup | $126.00 | $14.50 | 0 | $140.50 |
| Painting, 12 × 12 ft room, 8 ft walls, 1 door, 2 windows, 2 coats, $40 a gallon (starting values) | $200.00 | $80.00 | 2 | $354.20 |
| Painting, 3 coats at $38.50 a gallon | $200.00 | $115.50 | 3 | $399.11 |
| Drywall, 12 × 12 ft room, walls and ceiling, 4 × 8 sheets, 10% waste, $15 a sheet (starting values) | $200.00 | $255.00 | 17 | $575.58 |
| Drywall, walls only | $200.00 | $180.00 | 12 | $480.70 |
| Concrete, 12 × 10 ft slab × 4 in, 10% waste, 80 lb bags at $6 (starting values) | $200.00 | $444.00 | 74 | $814.66 |
| Concrete, 60 lb bags at $4.80 | $200.00 | $470.40 | 98 | $848.06 |
| Landscaping, 20 × 4 ft bed, 3 in of mulch, 5% waste, 2 cu ft bags at $5 (starting values) | $200.00 | $55.00 | 11 | $322.58 |
| Landscaping, 3 cu ft bags at $7.25 | $200.00 | $50.75 | 7 | $317.20 |
Sources and dates
The sources below show the day we read them. This page was reviewed on November 8, 2026.
- U.S. Bureau of Labor Statistics, Occupational Employment and Wage Statistics (OEWS), May 2025 state estimates (read )
- U.S. Bureau of Labor Statistics, Public Data API, version 1 (OEWS series) (read )
- Sherwin-Williams, Quali-Kote Interior Latex, Product Data Sheet (July 2020), coverage 350 to 400 sq ft per gallon (read )
- USG, Sheetrock UltraLightweight All Purpose Joint Compound coverage (FAQ) (read )
- QUIKRETE, Concrete Mix No. 1101 data sheet, revised October 2022 (read )
- NIST Special Publication 811, Appendix B (conversion factors) (read )