Help — How Calculations Work

Formulas

Gallons

(paint_area × coats × (1 + waste%)) ÷ spread_rating_sqft_per_gallon

Paint area (unit surfaces)

Trim/crown LF used directly; doors × 40 sf; windows × 10 sf; cabinets × 8 sf

Room walls (interior)

perimeter = 2×(L+W); wall net = perimeter×H − (doors×20 + windows×15)

Labor hours

first/additional coat rates when set; else (measure × coats) ÷ rate × condition

Prep hours

paint labor hours × prep%

Material $

gallons × price_per_gallon × (1 + markup%)

Labor $

(paint + prep hours) × blended_labor_rate

Sales rate

grand total ÷ total hours

Expand any surface row to see step-by-step show-work math. Condition multipliers: easy ×0.9, medium ×1.0, hard ×1.25.

Room-first workflow

1. Click Add Interior Room (or Exterior Surface).
2. Enter L×W×H, doors, and windows — walls/ceiling/baseboard auto-calc.
3. Choose which surfaces to include; coats, method, and product per surface.
4. Add extras (sundries, travel, disposal), set discount and prep %.
5. Export Markdown, PDF, or JSON — or open the printable proposal.

Spread rating (sq ft / gallon)

Each paint product has a spread rating — how many square feet one gallon covers. That rating is used for every surface that product is assigned to (walls, ceilings, exterior, etc.). Set a company standard in Settings → Std. spread sf/gal; customize per product in the Product Library. Typical latex paints land around 350–400 sq ft/gal; primers and rough/stucco surfaces often cover less.

Calibrating production rates

Default interior rates assume 2 coats, moderate residential (e.g. smooth walls ~90 sqft/hr, trim ~28 LF/hr). Calibrate to your crew — spray looks faster but must include backroll and masking.

1. Pick a completed room/job you know well.
2. Divide painted sqft × coats by actual man-hours spent on that surface.
3. Update Settings → Production Rates.
4. Re-estimate a known job and compare — iterate until it feels right.

Keyboard & workflow tips

• Start with the sample bedroom template (12×15×8, 2 doors, 2 windows).
• Wall calculator icon overrides irregular rooms with segment/opening math.
• Product Library is its own nav page; production rates stay in Settings.
• Accept estimate advances/creates a Job in Scheduled status.
• Import/export estimate JSON from the Estimates list; full backup in Settings.

Out of scope (later)

• Supabase Auth + multi-user / cloud sync
• Customer portal / public share links
• Actual vs estimate variance tracking
• AI photo takeoff / voice (Grok API slot)
• Scheduling, dispatch, invoicing