How to measure a cap for manufacturing

To measure a cap for manufacturing, record a fixed set of points of measure with the closure fastened: crown height at the front and at the side, front panel width, visor length, width and curve, the finished circumference inside the sweatband, sweatband height, the back opening, and the closure strap. For each point, state where it starts and ends and how the tape was held. Add the panel count, the structure and the closure type, because a cap is defined by its build as much as by its numbers.

Who this guide is for

This guide is for brands, designers and anyone preparing a cap specification for a manufacturer. It is not a hat size guide for shoppers. A shopper measures their head to choose a size. A brand measures a cap so that a pattern maker can rebuild it panel by panel, change it on purpose, and check the finished caps against it.

A cap is harder to specify than a t-shirt or a hoodie, for two reasons. It is three-dimensional, so it cannot be laid flat and measured edge to edge. And it is small, so an error that would vanish on a garment body is visible on a crown. Both are reasons to write down the method as well as the number.

Before you measure

• Fasten the closure. Set a snapback or strap to the position you actually wear, and note which position that is.
• Use a soft tape measure for the crown and circumference, and a rigid ruler for the visor. Work in centimetres to one decimal place, or in millimetres. If you work in inches, say so on every line.
• Keep a structured cap in shape. Do not flatten it. Rest it on a table or over your hand so the crown holds its form while you measure.
• Find the centre front. On a 6-panel cap it is the seam between the two front panels. On a 5-panel cap there is no seam, so fold the visor in half, mark the midpoint, and follow that line up the crown.
• Follow the surface on the crown. Crown measurements follow the curve of the cap. Visor measurements are straight lines unless you say otherwise.
• Write down the build. Panel count, structured or unstructured front, visor shape and closure type go at the top of the specification, before any numbers.

Cap points of measure

There is no single enforced standard for measuring a cap. Suppliers publish their own methods, and they agree on the main points: crown height from the button to the visor seam at centre front, visor length from the crown seam to the outer edge at centre, and front panel width from side seam to side seam along the bottom of the crown. The remaining points above are the methods we ask for. Whichever method you use, write it next to the number.

Crown and front panel

A. Crown height, front

Place the end of the tape on the centre of the top button. Run it down the centre front, following the curve of the crown, and stop at the seam where the visor joins. This is the number that decides whether a cap reads as low, mid or high profile, and it sets the height available for a front logo.

B. Crown height, side

From the centre of the button again, follow the seam between the side panel and the back panel down to the bottom edge of the cap. Front and side heights together describe the shape of the crown. A cap with a tall front and a short side sits upright; one with similar heights sits rounder and closer to the head.

C. Front panel width

Measure along the bottom of the crown, where the visor joins it, from the seam on one side of the front to the seam on the other. On a 6-panel cap that spans both front panels. On a 5-panel cap it is the width of the single front panel. This is the widest a front design can be before it runs onto a side panel, so it matters to the artwork as much as to the pattern.

If the front panels are much wider or narrower higher up, add a second width halfway up the crown and say where it was taken.

Visor: length, width and curve

D. Visor length

Hold a ruler under the centre of the visor. Measure from the seam where the visor meets the crown straight out to the front edge. Measure in a straight line, not over the curve of a pre-curved visor.

E. Visor width

Measure straight across the visor at its widest point, from the corner where it meets the crown on one side to the same corner on the other. On a curved visor a straight line and a line that follows the curve give different numbers. Use the straight line, or state that you followed the curve.

F. Visor curve

First describe it in words: flat, slightly curved or fully curved. To put a number on it, turn the cap to face you, hold a ruler across the two corners of the visor, and measure from the ruler up to the underside of the visor at its centre. A flat visor measures close to zero. The deeper the curve, the larger the number.

Note the visor edge shape too. A squarer front edge and a rounder one can share the same length and width and still look like different caps. A photo from directly above settles it faster than a description.

Circumference and sweatband

G. Finished circumference

Turn the cap over. Stand the tape on its edge and run it all the way round the inside, along the middle of the sweatband, until it meets itself. Take it with the closure fastened at the position you noted earlier.

For an adjustable cap, give two numbers: the circumference at the tightest setting and at the loosest. That range is what tells a manufacturer which head sizes the cap is meant to fit. For a fitted cap with no closure, the single number is the size, so measure it twice.

A head measurement is a different thing. It is taken around the widest part of the head, above the eyebrows and ears, and it tells you what circumference the cap needs to reach. Record both if you have them, and label each one.

H. Sweatband height

Measure the sweatband from its top edge to its bottom edge, flat against the inside of the cap. Note what it is made of and whether it runs the full way round or stops at the back opening. The sweatband is also where a woven label or a printed size mark usually sits, so say if you want one.

Back opening, closure and strap

Name the closure first: snapback, fabric strap with a buckle, hook-and-loop strap, elastic, or fitted with no opening at all. The measurements below apply to any cap with an opening.

I. Back opening width

Measure straight across the opening at the bottom edge of the cap, from one side of the opening to the other.

J. Back opening height

Measure from the bottom edge of the cap straight up to the highest point of the opening, at centre back. Width and height together define the arch. A wide, low arch and a narrow, tall one look quite different from behind.

K. Strap length and width

Unfasten the closure and lay the longer strap flat. Measure it end to end, then measure its width. For a snapback, count the snap positions and note the spacing between them. For a buckle strap, note the buckle type and whether the loose end tucks into a slot in the cap.

5-panel and 6-panel caps

The panel count changes what several of these measurements mean, so state it before anything else.

On a 5-panel cap, also record how the top of the front panel is shaped where it meets the panels behind it, because that line is part of the look. A photo of the cap from above is the simplest way to show it.

Other builds follow the same logic. A trucker cap has a front panel, often foam-backed, and mesh panels behind it, so note where the fabric stops and the mesh starts. If your cap has seven panels, or a front made in an unusual way, describe the panels in a sentence and measure each one that carries a design.

What the numbers do not show

Two caps can share every measurement in the table and still not be the same cap. Add these to the specification in words:

• Structured or unstructured. A structured cap has a stiffened front that stands up on its own. An unstructured one collapses when you put it down. This changes how the crown sits far more than a few millimetres of height.
• Fabric. Cotton twill, washed cotton, corduroy, ripstop, wool blend or mesh. Fabric weight and finish change how the crown holds its shape.
• Visor build. Flat or pre-curved, the number of rows of stitching, and the colour of the underside.
• Eyelets and top button. How many eyelets, whether they are stitched or metal, and whether the button is covered in the same fabric.
• Decoration and its position. Give the size of each design and the distance from a fixed point, for example from the visor seam up to the bottom of the logo. Raised embroidery behaves differently on a structured front; our custom cap page explains which methods suit which part of the crown, and our guide to how embroidery works covers what happens to small lettering in thread.

Tolerances

No factory makes every cap to the millimetre, so a specification includes a tolerance: the difference you will accept on each point. There is no single industry standard. The brand proposes tolerances and agrees them with the manufacturer.

Because a cap is small, the same error matters more than it would on clothing. Half a centimetre is invisible on the body of a hoodie and obvious on the height of a crown or the length of a visor. Set a tighter tolerance on the points people see first, which are crown height, visor length and the position of the front design, and agree all of them before bulk production, not after it arrives. Our hoodie measurement guide explains how tolerances work on a garment.

Common mistakes

• Flattening a structured cap to measure it. The crown has to keep its shape.
• Measuring the crown in a straight line when the specification means along the curve, or the other way round.
• Giving one circumference for an adjustable cap without saying which closure position it was taken at.
• Mixing up head size and cap circumference. They are related, and they are not the same number.
• Measuring visor width over the curve on one cap and straight across on the next.
• Leaving out the panel count. A 5-panel and a 6-panel cap with the same numbers are different patterns.
• Describing the profile in words only. "Mid profile" means different things to different makers. Give crown height.
• Forgetting the back. The opening and the strap are what people see from behind.

A spec table you can copy

Copy this table into a document or spreadsheet and fill it in. Add a tolerance for each row, and put the build details above it.

Beanies are measured differently

None of the points above apply to a beanie. A beanie is knitted to shape, not built from cut panels, so it has no crown seams, no visor and no closure. It is measured flat instead: the width across the opening, the full length from the top of the crown to the edge with any cuff unfolded, and the height of the cuff. Yarn and knit gauge matter as much as the numbers. That is a separate specification, and this guide stays with caps.

Measuring a cap for NO FUGAZI

You do not need a finished specification to work with us. Send the measurements above, or send photos of a cap whose shape you want from the front, side, back and above, and we build the pattern panel by panel. Either way the shape is proven on a sample before any bulk production, with one round of changes included, and our minimum is 50 pieces. See how we make custom caps and headwear, how we work without a tech pack, or send us your measurements on WhatsApp.

Questions

What measurements does a manufacturer need for a cap?

Crown height at the front and at the side, front panel width, visor length, width and curve, the finished circumference inside the sweatband, sweatband height, the width and height of the back opening, and the strap length and width. Alongside the numbers, state the panel count, whether the front is structured, and the closure type.

How do you measure crown height on a cap?

Place the tape on the centre of the top button and run it down the centre front, following the curve of the crown, to the seam where the visor joins. On a 6-panel cap that line is the centre seam. On a 5-panel cap, mark the centre by folding the visor in half.

How is cap circumference measured?

Inside the cap, along the middle of the sweatband, with the tape standing on its edge and the closure fastened. For an adjustable cap, give the circumference at the tightest and the loosest setting. A head measurement, taken around the widest part of the head above the eyebrows and ears, is recorded separately.

What is the difference between a 5-panel and a 6-panel cap when measuring?

A 6-panel cap has two front panels joined by a centre seam, so front panel width spans both and crown height follows the seam. A 5-panel cap has a single front panel with no centre seam, so front panel width is that one panel and the centre line has to be found by folding the visor in half.

How do you measure the curve of a visor?

Hold a ruler across the two corners of the visor and measure from the ruler up to the underside of the visor at its centre. A flat visor measures close to zero, and a deeper curve gives a larger number. Describe it in words as well: flat, slightly curved or fully curved.

Can I send a cap or photos instead of measurements?

Yes. A reference cap, or clear photos from the front, side, back and above with two or three key measurements, is often a more reliable brief than a full table. Our page on starting without a tech pack explains what to send.

Related reading

• How to measure a hoodie for manufacturing – the same method applied to a garment measured flat.
• How to make a tech pack – where these measurements sit in a full specification.