Free pleat calculator · 1:1 fold-mark ruler

Pleat Calculator (Skirts & Curtains)

Enter the finished waistband or curtain width and the pleat size you want. Get the exact pleat count, fold spacing, flat fabric width, yardage and a printable 1:1 marking ruler.

Knife, box, inverted & curtain
Inches or centimeters
Printable fold-mark ruler

Start calculating How it works

Illustration of a plaid pleated skirt on a hanger beside a sheer curtain, with an iron and a pleat ruler on a side table

Your measurements

Pleats

each 1 1⁄2" wide

Flat fabric width

85 1⁄4"

216.5 cm

Fold depth

1 1⁄2"

fabric per pleat 4 3⁄8"

Fabric widths to join

cut length 22 1⁄8"

Fabric to buy

1 1/4 yd

1.2 m

Fold marks (first 4 pleats)

M = mountain fold (fold toward you)V = valley fold (bring to the mark)

#	Fold	Mark at (in)	Alt
1	Mountain	2 1⁄8"	5.3 cm
1	Valley	3 5⁄8"	9.1 cm
2	Mountain	6 1⁄2"	16.6 cm
2	Valley	8"	20.3 cm
3	Mountain	11"	27.8 cm
3	Valley	12 3⁄8"	31.5 cm
4	Mountain	15 3⁄8"	39.0 cm
4	Valley	16 7⁄8"	42.8 cm
5	Mountain	19 3⁄4"	50.2 cm
5	Valley	21 1⁄4"	54.0 cm
6	Mountain	24 1⁄4"	61.5 cm
6	Valley	25 5⁄8"	65.2 cm

…26 more marks on the printable ruler.

The ruler prints the full flat width at 1:1 in strips you tape end to end, with every fold marked.

Free, no sign-up
Runs in your browser — nothing uploaded
True-scale 1:1 ruler with test squares
Inches & centimeters

Pleat types

Knife, box or inverted?

All three use the same amount of fabric for the same pleat size and depth — only the fold direction changes. The fold diagrams are drawn by the calculator for a 28" waist with 1 1/2" pleats.

Knife pleats
All folds face the same way — the classic kilt and school-uniform look. Easy to mark and press.
Use knife pleats
Box pleats
Two folds turn away from each other, leaving a flat panel on the outside. Structured and tailored.
Use box pleats
Inverted pleats
Two folds meet in the middle, so the fullness sits behind. Smooth front, swing when you walk.
Use inverted pleats

Knife, box and inverted pleats compared
Feature	Knife	Box	Inverted
Fold direction	All one way	Pairs turn away from each other	Pairs meet in the middle
Outside look	Overlapping folds	Flat panels	Smooth with hidden fullness
Fabric per pleat	P + 2D	P + 2D	P + 2D
28" waist, 1 1/2" pleats, D = P	19 pleats · 85 1⁄4" flat	19 pleats · 85 1⁄4" flat	19 pleats · 85 1⁄4" flat
Typical use	Kilts, tennis & uniform skirts	Tailored skirts, curtains	Skirt fronts, coat backs

How it works

Pleats in four steps

Step 1: Measure
Measure the finished width the pleats must fit — your waist plus ease, or the rod width a curtain panel covers.
Step 2: Enter
Choose knife, box, inverted or curtain, then enter a pleat width or a pleat count. The calculator rounds to whole pleats that divide the width evenly.
Step 3: Print the ruler
Download the ruler PDF, print at 100%, check the test squares and tape the strips end to end.
Step 4: Cut, mark & press
Cut the flat width, transfer the M and V marks to the fabric edge, fold, press and baste across the top.

Ruler, math & curtains

From numbers to pressed folds

A printable ruler, two simple formulas and a curtain mode — everything the results panel gives you.

Printable

Your printable pleat ruler

Measuring every fold with a tape is where pleats go wrong. Download a 1:1 PDF ruler, tape the strips end to end along the waist edge and transfer the marks with chalk or pins.

Open this example

What is printed on the ruler

Solid lines (M) are mountain folds; dashed lines (V) are valley folds. Arrows show the press direction.
2" and 5 cm test squares on page 1 confirm you printed at 100%.
Numbered strips with join triangles, on US Letter or A4. The preview is page 1 of the real PDF for the 19-pleat, 28" knife example.

First three knife pleats: solid = mountain, dashed = valley

The math

Each pleat uses P + 2D of fabric

A pleat tucks two layers of depth D behind the visible width P. With D = P you need three times the waist: 28" with 1 1/2" knife pleats becomes 19 pleats and 85 1⁄4" of flat fabric.

Knife vs box pleats guide

Show the pleat formulas and fold-mark key

pleats N = round(W ÷ desired width)
exact width P = W ÷ N
flat width = W + 2 × N × depth + 2 × side SA
fabric widths = ceil(flat width ÷ usable fabric width)

Exact width for the example: P = 28 ÷ 19 = 1.474". Box and inverted pleats use the same fabric; only the fold direction changes.

M (solid) — crease so the line is on the outside edge of the fold. V (dashed) — where the fold lands; bring the mountain fold to it.

Curtains

Pinch-pleat curtains, evenly spaced

Switch to Curtain mode and enter the width each panel covers and the fullness. A 50" panel at 2.5× gets 12 pleats of 6 1⁄4", spaced 3 7⁄8" apart on a 125" header.

Try curtain mode

Worked examples

Real numbers, straight from the calculator

Worked example

Knife-pleated skirt

Waist: 28"
Pleat width: 1 1/2"
Length: 20"
Fabric width: 60"

Open in calculator

Result

Pleats: 19 × 1 1⁄2"
Fold depth: 1 1⁄2"
Flat width: 85 1⁄4"
Fabric to buy: 1 1/4 yd (1.2 m)

Worked example

Box-pleated skirt in centimeters

Waist: 71 cm
Pleat width: 6 cm
Length: 50 cm
Fabric width: 150 cm

Open in calculator

Result

Pleats: 12 × 5.9 cm
Fold depth: 5.9 cm
Flat width: 216.0 cm
Fabric to buy: 1.2 m (1 1/4 yd)

Worked example

Pinch-pleat curtain panel

Width per panel: 50"
Fullness: 2.5×
Return / overlap: 3 1/2" / 3 1/2"
Panels / drop: 2 × 96"

Open in calculator

Result

Pleats per panel: 12
Space between: 3 7⁄8"
Fabric widths / panel: 3
Fabric to buy: 16 yd (14.7 m)

Tips

Tips for crisp pleats

Baste before the band
Mark and press pleats on the flat fabric, then baste across the top edge before attaching the waistband.
Match the plaid
Plaids look best when the pleat width matches the plaid repeat — enter the repeat as the pleat width.
Hem first
When the hemline is straight, hem before pleating — much easier than hemming across pressed folds later.
Prefer gathers?
Try the tiered skirt calculator. Want flare without folds? Use the circle skirt calculator.

Frequently asked questions

How much fabric do I need for a pleated skirt?

With full-depth pleats, you need about three times your waist in fabric width, plus seam allowances. Shallower pleats need less. The calculator figures the exact flat width and how many fabric widths to join.

How do I calculate the number of pleats?

Divide your finished width by your target pleat size and round to a whole number. Then divide the finished width by that count to get the exact individual pleat width.

What is the difference between knife and box pleats?

Knife pleats fold in one direction. Box pleats fold two pleats away from each other into a flat panel; inverted pleats meet in the centre. Compare them in our guide to knife vs box pleats.

Is the pleat ruler PDF true to scale?

Yes. Print at 100% on A4 or Letter and check the 2" and 5 cm test squares before taping the strips together.

Can I make shallower pleats to save fabric?

Yes. Enter a fold depth smaller than the pleat width. Each pleat then uses the pleat width plus twice the depth, so the flat width and yardage drop.

How do I share my pleat settings?

Click “Copy share link” above the calculator. The pleat type and measurements are stored in the link, so opening it restores the same result. Nothing is stored on a server.

Ready to fold your pleats?

Enter the finished width and pleat size — get the pleat count, flat width and a 1:1 fold-mark ruler in seconds.

Start calculating

Pleat Calculator (Skirts & Curtains)

Fold marks (first 4 pleats)

Knife, box or inverted?

Knife pleats

Box pleats

Inverted pleats

Pleats in four steps

Step 1: Measure

Step 2: Enter

Step 3: Print the ruler

Step 4: Cut, mark & press

From numbers to pressed folds

Your printable pleat ruler

Each pleat uses P + 2D of fabric

Pinch-pleat curtains, evenly spaced

Real numbers, straight from the calculator

Knife-pleated skirt

Box-pleated skirt in centimeters

Pinch-pleat curtain panel

Tips for crisp pleats

Baste before the band

Match the plaid

Hem first

Prefer gathers?

Frequently asked questions

Related calculators

Ready to fold your pleats?