Painter: Gallons Of Paint From Area And Coats

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Paint cans are sold in whole gallons, and a second coat doubles the area you have to cover. This recipe multiplies the paintable area by the number of coats, divides by the coverage per gallon on the can and rounds up, then prices the order.

Quick formula: Area times coats divided by coverage per gallon, rounded up:

=ROUNDUP(B2*C2/D2,0)

1,120 sq ft, 2 coats at 350 sq ft per gallon is 7 gallons, or $266 at $38 a gallon.

Functions used (tap for the full reference guide):

ROUNDUP IF

The example

Three jobs with different coats and coverage. Primer and rough surfaces cover less per gallon.

	A	B	C	D	E	F	G
1	Case	Area	Coats	Per gallon	$/gal	Gallons	Cost
2	Whole house	1,120	2	350	$38.00	7	$266.00
3	Bedroom	640	2	400	$45.00	4	$180.00
4	Exterior	1,800	1	350	$38.00	6	$228.00

The formula

Total area to cover divided by what one gallon covers, rounded up:

=ROUNDUP(B2*C2/D2,0) // gallons; cost = gallons * price per gallon

How it works

Here is the logic, one piece at a time:

B2*C2 is the total square footage to cover across all coats.
Dividing by D2, the coverage per gallon, gives gallons as a decimal.
ROUNDUP(...,0) converts to whole cans because you cannot buy 6.4 gallons.
Multiplying gallons by the price in E2 prices the order.

Pair this with the billable wall area recipe to subtract doors and windows first.

Try it: interactive demo

Interactive

Enter the area, number of coats, coverage and price per gallon.

Paintable area (sq ft)

Number of coats

Coverage per gallon (sq ft)

Price per gallon ($)

Variations

Round to five-gallon buckets

Use CEILING to price by bucket size when the job is large.

=CEILING(B2*C2/D2,5)/5

Add a touch-up allowance

Add 5% to cover touch-ups and spills before rounding up.

=ROUNDUP(1.05*B2*C2/D2,0)

Pitfalls & errors

Coverage on the can assumes smooth, primed surfaces; textured walls and bare drywall absorb more.

A rounded-down order leaves you short and risks a visible color batch change mid-wall.

Have the paint store mix all gallons for a room into one larger pail to avoid batch differences.

Practice workbook

📊

Download the free Painter: Gallons Of Paint From Area And Coats practice workbook

Edit the yellow area, coat, coverage and price cells; gallons and cost recalculate.

Frequently asked questions

What coverage per gallon should I use?

Most interior paints cover 350–400 sq ft per gallon on prepared walls.

Should ceilings be included?

Add the ceiling area to the wall area if they get the same paint, or run a second row for a ceiling paint.

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Function references: ROUNDUP IF