Fold a piece of paper into two equal parts? Quarter a piece of paper? Still no problem. Fold a sheet of paper into perfect thirds? That could be a challenge. Anyone who has ever had to fold an important letter in three will tell you that it takes quite a bit of finesse to get it done neatly. Whether you’re writing your sweetheart a letter, turning it into a math project, or simply want to fold your note paper into three equal pieces, an accurately folded piece of paper shows professionalism and attention to detail.

Table of Contents

- 1 The intuitive method
- 1.1 Lay your paper flat on your work surface.
- 1.2 Roll the paper into a loose cylinder.
- 1.3 Align the edges of the sheet, so they line up, then gently press down on the roller in the center.
- 1.4 Once you’ve made sure the three pieces are the same size and the edges line up nicely, flatten the cylinder completely.

- 2 The method with the “pattern paper”
- 3 The method of eye
- 4 The origami method
- 4.1 Fold the piece of paper in half.
- 4.2 Now draw a line from the bottom left corner to the top right corner of the bottom part.
- 4.3 Draw another line from the top left corner of the paper to the bottom right corner.
- 4.4 Fold the paper once where the two lines intersect.
- 4.5 Now make the second fold by sliding the top edge under the unfolded part of the sheet and lining up the edge exactly with the fold (as described in the method by eye).

- 5 Divide the sheet into thirds using pure mathematics

## The intuitive method

### Lay your paper flat on your work surface.

Believe it or not, there are quite a few ways to fold a piece of paper into three equal parts, but some give better results than others. You can try this method if you don’t need to be precise — it’s quick and works well, but it’s rarely accurate to the millimeter. What speaks for this method: You do not need extra tools. Don’t forget that a regular sheet of paper measuring 8.5 × 11 inches doesn’t necessarily have to be folded in perfect thirds to fit in an envelope. This size is, therefore, particularly suitable for correspondence.

### Roll the paper into a loose cylinder.

Your goal is to roll up your piece of paper to look like a rolled-up newspaper. Don’t fold the paper just yet; just roll it up.

### Align the edges of the sheet, so they line up, then gently press down on the roller in the center.

Look at your cylinder from the side — ideally, the right and left edges of the paper should be right across from each other. Now press the cylinder together and always align the edges straight, so they lie nicely on each other. The three layers of paper created this way should be approximately the same width. Therefore, make sure that one edge of the paper lies within the cylinder on the fold. The other edge of the paper is outside the cylinder on the fold on the other side. Now that sounds insanely complicated, but if you try it, you will see that it is very easy and automatic.

### Once you’ve made sure the three pieces are the same size and the edges line up nicely, flatten the cylinder completely.

When you see that your paper is divided into (nearly) perfect thirds, press it down flat and rub along the edges with some pressure to get nice and balanced creases. Congratulations! Your sheet of paper is now folded into (almost) perfect thirds. Now you can make one final tweak, but be careful not to make more than a fold in one place unless your thirds are very irregular — it will look very unprofessional otherwise.

## The method with the “pattern paper”

### Fold a piece of note paper into approximate thirds.

This method requires a piece of paper to fold another into perfect thirds. So you need two sheets of paper for this method — one that you want to fold perfectly and a second that will serve as a pattern that you won’t need later. The two sheets should be the same size. Fold your pattern paper into roughly thirds using a method that suits you — you can use the “intuitive” method above or any other described in this article. You can also just try it out until you are satisfied with the thirds. You only need this sheet as a template.

### Keep folding until the thirds are as accurate as possible.

Then keep improving until you’ve folded the paper into almost perfect thirds. Don’t worry if you have to unfold the paper countless times or if the creases are ugly—this is just your pattern paper and will not be used later.

### Then use your sample paper if you want to fold the “right” paper.

When you are happy with your pattern folds, place it next to your second piece of paper, the one you plan to mail. Now fold the second paper exactly according to the pattern of the first. You can either mark the folds from the first sheet on the second or use your eyesight to compare the two sheets.

### Use a straight edge to help.

If it helps you, you can also use a straight edge (e.g. the edge of a table or the edge of your envelope) to align the sheets. Align the two sheets along this straight edge. This can help you mark the creases from the pattern paper on the “real” paper. Using a solid edge, you can also fold your “real” paper over it to get your folds even more precise. When you’re done, don’t throw away your pattern paper—you may need it for note paper or for next time. Don’t just throw paper that’s still usable in the wastebasket.

## The method of eye

### Fold one of the edges onto the paper from the bottom up.

With this method, you’re just using your eye to fold a piece of paper into perfect thirds. Although that doesn’t sound very accurate, the method is very effective. Once you’ve practiced them a few times, you’ll be able to fold really important letters perfectly. So first, you take the bottom edge of the paper and fold it up, sort of over the rest. Don’t fold the paper yet — the crease you’re about to make should only show as a slight curve in the paper.

### Position the edge, so it covers about half of the paper.

Try to fold the bottom edge of the paper to cover half of the remaining piece of paper. It’s a lot easier for the human eye to estimate half of a given size than a third, so it’s much easier to focus on half of the remaining two-thirds than to fold a third of the paper. This all sounds very complicated again, but if you look at the pictures and try it yourself, it should become clear. When you’ve placed the edge of the paper in the middle of the top two-thirds, fold the paper. Make sure that the edge does not shift again when folding.

### Now fold the top edge along the bottom fold, creasing the top two-thirds of the paper.

The hardest part is already behind you. All you have to do now is fold the last third. To do this, take the top edge of the paper and fold it so it lies on the fold, i.e. under the already folded paper. Smooth out the fold. If you have folded it exactly, all paper edges should now lie nicely on each other. If they don’t exactly match, you can still adjust that now if you think it’s necessary.

## The origami method

### Fold the piece of paper in half.

This method is based on origami techniques. Origami is the Japanese art of folding paper. Although origami usually uses squares, this method works with regular A4 paper, which you can find in any office. First, fold the paper in half (lengthwise), in the same direction as you would also fold the paper into thirds. Note: If you don’t want additional creases to show, you can also measure the center of the paper and mark it with a fine pencil line. But you have to make sure that the line is perfectly straight.

### Now draw a line from the bottom left corner to the top right corner of the bottom part.

Position the sheet so the line or fold that marks half the sheet runs left to right. Then, using a ruler, draw the line described above, from the bottom left corner to the point where the center line intersects the right edge of the paper. Of course, you can also reverse this method, i.e. draw a line from the lower right corner to the point where the middle line meets the left edge, and then do all other entries mirror-inverted. But since the whole thing is complicated enough, we’ll content ourselves with just one statement.

### Draw another line from the top left corner of the paper to the bottom right corner.

Use your ruler for this as well. This line should intersect the center line right down the middle and the first line you drew on the bottom right half of the paper.

### Fold the paper once where the two lines intersect.

The point where the two drawn lines intersect marks where the sheet needs to be folded for the bottom third. Use a ruler to draw a line that goes through this point and is parallel to the bottom edge of the sheet. Now carefully fold the sheet along this line and smooth the fold. The folded edge should now divide the rest of the sheet in half as well — if it doesn’t, you may need to make minor adjustments, so the bottom edge matches the Divide the rest of the paper into two halves.

### Now make the second fold by sliding the top edge under the unfolded part of the sheet and lining up the edge exactly with the fold (as described in the method by eye).

Once the edge is snug against the fold, smooth out the second fold. Your sheet should now be folded into three even parts.

## Divide the sheet into thirds using pure mathematics

### Measure one side of your sheet.

Are you not completely convinced of the procedures described above? Couldn’t you fold the paper precisely enough? Try the steps described here; you probably won’t be able to cut your sheet of paper into thirds more precisely. You will need a ruler, a calculator, or a piece of note paper to write your calculations on. First, measure the long side of the sheet you want to fold.

### Then divide that number by three.

This gives you the height of each third. If you’re using regular 8.5 × 11 inch paper and you want to divide it in thirds lengthwise, simply divide 28 by 3 and you’ll get the height of each third. 28 divided by 3 equals 9.3, so your pleats should be 3.75 inches apart.

### Mark the distance by measuring from the bottom edge.

Using your ruler, measure the 9.3 cm and mark the point where you want to make a line. Measure along the long side of the leaf you want to divide into thirds. So in our example with the piece of paper that is 21.6 × 28 cm, we would measure 9.3 cm on the side that is 28 cm long.

### Fold the paper at this point and then fold the top part over it.

Make sure that you fold the paper perpendicular to the long edge. This is sort of the first of the folds you use to divide the sheet into thirds. The second is much easier — just fold the top edge under the already folded part of the paper and line the edge up so that it lines up exactly with the crease you’ve already made (just as described above).