How much wrapping paper you need, ribbon included

Wrapping paper calculator: the size of the piece

For a box, the piece of paper measures 2 × (width + height) + overlap one way and length + height + overlap the other way. The box lies on its biggest face, so the height is its shortest side: you can enter the three measurements in any order and the calculator sorts them.

The first side goes around the box: over the bottom, one side, the lid and the other side, with the overlap where the two edges meet on the lid. Farhi's guide says to add about 2.5 cm. The calculator starts from 1 in in US units and 2.5 cm in metric.

The second side covers the length of the box plus the two ends. At each end the paper sticks out by half the height plus half the overlap: the top flap folds down, the bottom flap folds up, and they overlap in the middle. Farhi gives a 5.5 cm flap for a box 10 cm tall, just over half. On a box 4 in tall the calculator leaves 2 1/2 in.

You can wrap the paper around the long side of the box or around the middle side. Without the overlap both pieces have the same area but a different shape, one longer and narrower than the other. The calculator tries both ways, and both directions on the roll, and keeps the one that uses the least roll for the number of presents. When several identical pieces fit side by side across the roll, it cuts them in the same row.

Each row comes off one roll. Rows go into the rolls longest first, each into the first roll with room left. With sheets the count goes box by box: how many pieces fit on one sheet and how many sheets that takes.

For ribbon tied in a cross the length is 2 × length + 2 × width + 4 × height, plus the bow. That is the formula in Lazada's ribbon guide, which adds 30 to 45 cm, 12 to 18 in, for a two-loop bow with tails. We start from the top of that range. Each present needs one whole piece, so spools are counted the same way as rolls.

A worked example

Two shirt boxes of 17 × 11 × 2 in and a shoe box of 14 × 8 × 5 in, a 30 in × 16 ft roll, 1 in overlap, 18 in for the bow and 18 ft ribbon spools. These are the values the calculator opens with in US units.

• Shirt boxes: wrapped around the middle side, the piece is 2 × (17 + 2) + 1 = 39 in by 11 + 2 + 1 = 14 in. Two pieces side by side take 28 in of the 30 in roll, so both come out of one 39 in row. The usual 27 × 20 in piece would take two rows, 40 in.
• Shoe box: 2 × (8 + 5) + 1 = 27 in by 14 + 5 + 1 = 20 in, with the 27 in side across the roll: 20 in of roll.
• Roll used: 39 + 20 = 59 in, 4' 11", so 1 roll of 40 sq ft.
• Ribbon: 2 × 17 + 2 × 11 + 4 × 2 + 18 = 82 in for each shirt box and 2 × 14 + 2 × 8 + 4 × 5 + 18 = 82 in for the shoe box, 246 in in all (20 ft 6 in, 6.8 yd). An 18 ft spool holds two pieces: 2 spools.

With 20 × 30 in sheets each box needs a 27 × 20 in piece, one per sheet: 3 sheets.

In the UK, in metric: a shoe box of 33 × 20 × 12 cm and three books of 24 × 17 × 3 cm on a 70 cm × 2 m roll. The shoe box takes a 66.5 × 47.5 cm piece, 47.5 cm of roll. The books, wrapped around the middle side, take 56.5 × 22.5 cm pieces, three side by side in a single 56.5 cm row. That is 1.04 m of roll, so 1 roll. The ribbon comes to 6.16 m: two 4 m reels.

Piece sizes for common boxes

1 in overlap, 18 in for the bow, 30 in × 16 ft roll. The numbers come from the calculator.

Box (in)	Piece (in)	Gifts per roll	Ribbon
10 × 7 × 2	25 × 10	21	60 in
15 × 9 1/2 × 2	24 × 18	10	75 in
17 × 11 × 2	27 × 20	9	82 in
12 × 12 × 6	37 × 19	5	90 in
20 × 14 × 5	39 × 26	4	106 in

The 12 × 12 × 6 in box needs a 37 × 19 in piece. It will not come out of a 20 × 30 in sheet, but it does come off a 30 in roll, because the 19 in side goes across.

Rolls, sheets, ribbon and tape in the shops

In the US many wrapping paper rolls are 30 in wide and labeled in square feet. A 30 in roll gives 2 1/2 sq ft per foot of length, so the Hallmark 40 sq ft roll is 16 ft long: divide the square feet by 2.5 to get the length to enter. In Europe you find rolls of 70 cm × 2 m or 3 m, like the Clairefontaine ones sold by La Poste. Flat sheets are sold in sizes like 20 × 30 in in the US and 50 × 70 cm in Europe, which The Pepin Press calls the standard size for gift wrap.

Ribbon is sold on spools of every length, from a few feet to hundreds of yards. An Offray satin spool of 5/8 in × 18 ft covers two medium presents. For a big pile of gifts a long spool is cheaper: enter its length and the calculator counts the spools without splitting a piece.

Tape is optional. With the folds above, three pieces close a present: one on the seam of the lid and one on each end. You set the length of each piece in the advanced options; it starts at 2 in. With three 2 in pieces per present, a Scotch Magic roll of 3/4 × 1000 in does 166 presents.

Common mistakes

• Counting only the surface of the box. The 14 × 8 × 5 in shoe box has 444 sq in of surface, but the piece that wraps it is 540 sq in: about 22% more, from the overlap and the ends.
• Leaving a full height at each end. For the same box the piece would grow from 20 to 25 in, and the ends turn thick and lumpy.
• Always cutting the same way. For the three books of the UK example the usual piece uses 85 cm of roll, the turned one 56.5 cm.
• Buying sheets for big boxes. The 12 × 12 × 6 in box in the table does not fit a 20 × 30 in sheet: if the receipt says a present is "bigger than the paper", switch to a roll.
• Cutting ribbon from the wrong spool. Each present needs one whole piece: after two 82 in pieces, an 18 ft spool has 52 in left, too short for a third.