gizmobench

Gift Wrapping Paper Calculator

Give this calculator a box, a seam overlap and the width of your paper roll, and it sizes the sheet twice, once for each way round the box. A 12 x 8 x 4 in box with a 1 in seam wants a 25 x 21 in sheet with the seam running along the length: the paper crosses the 8 and the 4 twice and then laps itself, 2 x (8 + 4) + 1 = 25, and it stands 4.5 in past each end so the flaps can fold in. Turn the same box and the sheet becomes 33 x 17 in. On a 30 in roll that is 21 in pulled off the roll instead of 33 in, which is the whole reason the page works it both ways and names the cheaper one. Measurements go in as inches or centimetres, as decimals or as fractions such as 7 1/4, and the arithmetic behind every line is printed under it. Nothing is uploaded, nothing is gated and the plan copies or prints in one button.

Box 12 x 8 x 4 inOverlap 1 inRoll 30 inEnds 4.5 in
Gift wrap sheet
Box 12 x 8 x 4 in, seam overlap 1 in
End folds 4.5 in at each end: the shallower side of the end face plus half the seam
Roll 30 in wide

Lengthwise: sheet 25 x 21 in, 21 in off the roll, 17% of that strip trimmed away
  around 2 x (8 + 4) + 1 = 25, along 12 + 2 x 4.5 = 21
Crosswise: sheet 33 x 17 in, 33 in off the roll, 43% of that strip trimmed away
  around 2 x (12 + 4) + 1 = 33, along 8 + 2 x 4.5 = 17

Best: lengthwise, 21 in off the roll.
Measured in
Sheet
25 x 21 in
Off the roll
21 in
Orientation
Lengthwise
Fits
Yes

Lengthwise wastes less: a 25 x 21 in sheet, 21 in off a 30 in roll.

Crosswise takes 33 in off the same roll. The strip you pull for the pick is 630 sq in against a 525 sq in sheet, so 17% of it is trimmed away.

Worked examples

Each row is run through the same arithmetic as the form above, so none of them can drift away from it. Use loads the row into the fields.

  • 12 x 8 x 4 box, 1 in seam30 in roll, lengthwise
    25 x 21 in, 21 in off the roll
  • Turned the other waythe same box, crosswise
    33 x 17 in, 33 in off the roll
  • Long box, narrow roll20 x 4 x 4 on a 15 in roll
    49 x 13 in, 49 in off the roll
Accuracy. Exact arithmetic on the box, the seam overlap and the end folds you set, worked both ways round so you can pick the one that wastes less. It assumes a rectangular box and a plain sheet, and plans no nesting of several presents. The sheet goes round one girth of the box, 2 x (side + side), and the seam overlap is added to that once. The end fold, left empty, is the shallower side of the end face plus half the seam, which is what the flaps from the two widest faces have to cover; type your own figure if you tuck deeper. A sheet fits the roll when one of its two sides is no wider than the roll, and what you pull off is the other side.

Common questions

How much wrapping paper do I need for a box?
Enough to go all the way round one girth of the box and lap itself at the seam, and enough to stand past both open ends for the flaps to fold in. Round the box the sheet measures 2 x (side + side) + overlap, and along the box it measures the remaining side + 2 end folds. For a 12 x 8 x 4 in box with a 1 in seam that is 2 x (8 + 4) + 1 = 25 in around and 12 + 2 x 4.5 = 21 in along, so a 25 x 21 in sheet. This page works that out for both ways round the box at once, because the same box also wraps as 33 x 17 in with the seam along the width.
How much overlap should I leave at the seam?
That is your figure, not the calculator's: it is added to the way round exactly once, so whatever you type is what the sheet gets. An inch, or two to three centimetres, is enough to hold tape on the straight seam of a plain box. Type 0 and you get a butt join with the two edges meeting, which is the least paper that can still go all the way round. The end folds also pick up half the seam when they are left on auto, so the two flaps that close each end overlap each other rather than merely meeting.
What if the sheet is wider than my paper roll?
The sheet turns on the roll first. A sheet fits when either of its two sides is no wider than the roll, and the side you pull off is the other one, so a 33 x 17 in sheet still comes off a 30 in roll: 17 in lies across the roll and 33 in comes off it. When the narrower side is wider than the roll, that way round is marked as not fitting and the reason names your roll width. If neither way round fits, the plan says so and your options are a wider roll or two sheets joined along a seam.
How much paper do the folded ends need?
Left empty, the end fold is the shallower side of the end face plus half the seam overlap, which is 4.5 in on each end of a 12 x 8 x 4 in box with a 1 in seam. The flaps that close an end come off the two widest faces and fold over the shallow side of that end, so that side is the depth they have to cover, and the half seam is what makes them overlap. If you tuck deeper, or you fold the ends flat and tape them, type your own figure into the end fold field and the arithmetic uses it exactly.
Which way round the box wastes less paper?
The one that takes fewer inches off the roll, because the roll width is fixed and a shorter pull is less paper. The tool measures both, checks each against your roll and names the pick. For the 12 x 8 x 4 in box on a 30 in roll, lengthwise pulls 21 in and crosswise pulls 33 in, and the strip you cut is 30 x 21 in against a 25 x 21 in sheet, so 17 per cent of that strip is trimmed away. It plans one box at a time and does not try to nest several presents into one strip.
Does it work in centimetres as well as inches?
Yes, and switching the unit converts what you already typed rather than clearing it, rounded to two decimals, so a 12 in side becomes 30.48 cm and a 30 in roll becomes 76.2 cm. Each unit carries its own sensible ceiling for a box, a seam and a roll. Fractions read in either unit, so 7 1/4 and 7.25 are the same measurement, and the plan is written in whichever unit you are working in.

Exact arithmetic on the box, the seam overlap and the end folds you set, worked both ways round so you can pick the one that wastes less. It assumes a rectangular box and a plain sheet, and plans no nesting of several presents.