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Painting Gallons Calculator

Room dimensions + coat count → exact gallons of paint needed with 10% buffer.

Where this fits

📦 Business & Seller OpsGoing 1099FreelancersFounders

This tool lives inside Going 1099 and is most useful for freelancers and founders.

Corp Tax Rate21%
SE Threshold$400
FICA Cap 2024$168,600

Room Details

Total gallons
3.7
incl. 10% buffer
Wall gallons
2.4
2 coats
Ceiling gallons
1.0
2 coats
Quarts needed
15
if buying quarts
1

Wall area

wallArea = 2 × (length + width) × height

= 2 × (14 + 12) × 9

= 468 sq ft

2

Openings deducted

deductions = (doors × 21) + (windows × 15)

= −51 sq ft

Professional painters often skip deducting openings on small rooms

3

Gallons per coat (walls)

gal = netWallArea ÷ coverage

= 417 ÷ 350

= 1.2 gal / coat

350 sq ft/gal is a standard assumption; premium paints can cover 400+

4

Total gallons (walls)

total = gal per coat × coats

= 1.2 × 2

= 2.4 gal

5

Total + 10% buffer

= 3.7 gal

Always buy 10% extra — dye lots vary and touch-ups may be needed

Key insight

One gallon of paint covers roughly 350 sq ft with one coat. Dark or saturated colors may need 3 coats. Always buy from the same dye lot — colors vary between batches even in the same shade.

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