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Wallpaper Calculator

Wall area plus a pattern-matching waste allowance, divided by usable coverage per roll.

Wall area (sq ft)

Waste factor (%)

Rolls needed

Pattern repeats can waste more material — bump the waste factor up for large or busy patterns.

What you entered

Wall area (sq ft): 300Waste factor (%): 15

1
Add 15% for pattern matching waste
300 × 1.15= 345 sq ft
2
Divide by usable coverage per roll (~50 sq ft: a European roll or a US double roll)
345 ÷ 50= 7 rolls

Result

Rolls needed: 7

300 sq ft of wall needs about 7 standard wallpaper rolls.

Wallpaper rolls needed for common room sizes with 8 ft ceilings

Wall area here is the room perimeter multiplied by an 8 ft ceiling height, with no deduction for doors or windows. Roll counts come straight from this calculator, which divides the wasted-up area by about 50 sq ft of usable coverage per roll and rounds up to a whole roll. That 50 sq ft is a European roll or a US double roll; a US single roll covers only about 28 sq ft, so buying singles takes roughly twice these counts.

Room size (ft)	Wall area (sq ft)	Rolls at 10% waste	Rolls at 15% waste	Rolls at 20% waste
8 x 10	288	7	7	7
10 x 10	320	8	8	8
10 x 12	352	8	9	9
12 x 12	384	9	9	10
12 x 14	416	10	10	10
12 x 16	448	10	11	11
14 x 16	480	11	12	12
14 x 20	544	12	13	14
16 x 20	576	13	14	14

Use 10% waste for a small or random pattern, 15% for a repeat of roughly 6 to 12 inches, and 20% for a large repeat of 12 inches or more. Because rolls are whole units, a higher waste factor often lands on the same count. A 9 ft ceiling raises every wall area by about 12%, so recompute rather than reusing these rows. Skipping the door and window deduction leaves a deliberate cushion for cutting; if your room has an unusually large window wall, measure the openings and subtract them. Buy every roll from the same dye lot, and add one spare roll for future patch repairs.

How to calculate wallpaper rolls needed

Measure the total wall area: add up (wall length × ceiling height) for each wall, then subtract windows and doors. Add 10–15% for waste, divide by the usable coverage per roll, then round up to a whole roll. This calculator uses about 50 sq ft of usable coverage — the figure for a European roll or a US double roll, which is how almost all wallpaper is sold today. If you are buying US single rolls at roughly 28 sq ft each, you need close to double the count it reports.

Pattern repeat and waste

Wallpaper with a large pattern repeat (12"+ or more) wastes significantly more material because each strip must align with the next. A 24" repeat on 10-foot walls can waste 20% or more per strip. Check the repeat size on the label and increase your waste allowance accordingly. Small or random patterns waste very little.

Wallpaper roll sizes explained

A US single roll is 27" wide × 13.5 ft long — about 30 sq ft gross, or roughly 28 sq ft usable after trimming. A European roll runs about 21" × 33 ft, close to 57 sq ft gross and roughly 50 sq ft usable, and a US double roll works out to about the same. Double rolls also give you longer, more economical strips for tall walls. Always check which standard your wallpaper uses — usable coverage differs by a factor of two between a single roll and a double.

Tips to avoid running short

Buy all rolls from the same dye lot — colors vary between production runs. Order 1–2 extra rolls beyond your calculation for mistakes and future repairs. Unopened rolls can usually be returned. Running out mid-room and reordering risks a visible color shift.

Frequently asked questions

How many rolls of wallpaper do I need for a room?

Measure all wall surfaces (length × height), subtract doors and windows, add 10–15% for waste, then divide by the usable coverage per roll — this calculator uses about 50 sq ft, the usable area of a European roll or a US double roll. A 12×12 ft room with 8-foot ceilings has 384 sq ft of wall, which comes out at 9 rolls with a 10–15% waste factor and 10 rolls at 20%. The same walls would take about 16 US single rolls.

How much does a roll of wallpaper cover?

A US single roll covers about 28 sq ft of usable area (30 sq ft gross, minus trimming). A US double roll covers about 56 sq ft gross and roughly 50 usable. A European roll (about 21" × 33 ft) is close to 57 sq ft gross and roughly 50 usable. This calculator assumes 50 sq ft per roll, so the count it gives you is in double rolls or European rolls — check the label for the specific paper you're buying.

How do I account for pattern repeat waste?

Check the pattern repeat length on the wallpaper label. For repeats under 6 inches, add 10% waste. For 6–12 inch repeats, add 15%. For 12–24+ inch repeats, add 20–25%. Large pattern repeats on tall walls waste the most material because each strip must align.

Should I buy extra wallpaper rolls?

Always buy 1–2 extra rolls beyond your calculated need. They cover mistakes during hanging, future repair patches, and account for slightly more waste than expected. Buy from the same dye lot — colors vary between production batches. Unused, unopened rolls can usually be returned.