Find your fit.
Cap Size Guide
A comfortable cap starts with head circumference. Measure first, then compare the shape and adjustment of the model you want.
Find your circumference
For your measurement, remove your cap. Wrap a soft tape around your head, just above your eyebrows and ears. Keep it level and comfortably snug.
Your size at a glance
Pro
55–61 cmFlow · Motion · Pulse · Aero · Focus
Originals
54–60 cmGeneral adult range. Check model-specific exceptions.
Kids M
45–49 cmChoose by head circumference, not age.
Kids L
49–54 cmMeasure with the tape level above ears and eyebrows.
Bucket hats
54–59 cmFit guideline · nominal size 59 cm · no snap adjustment.
Family sets
Originals + KidsOne adult Originals cap plus one kids cap in M or L. Measure each wearer separately.
How to measure your head
- Remove your cap. Wrap a soft measuring tape around the widest part of your head, just above your eyebrows and ears.
- Keep the tape level around the back of your head. It should sit comfortably against the skin without digging in.
- Read the circumference in centimetres. Repeat once to check the result. No soft tape? Use a non-stretch string, mark the overlap and measure the string with a ruler.
- Compare that number with the model’s stated range. Measure each person separately when buying a family set.
Choose the right range
These are the Blackskies range guidelines. Some Originals product pages list model-specific differences: check those before ordering.
Size & shape
Pro: one range, different shapes
55–61 cm
The Pro range covers Flow, Motion, Pulse, Aero and Focus. The circumference range is shared; crown construction and brim shape still change the feel. A more structured Flow does not sit like a soft Aero, even at the same adjustment.
Explore the collection →
Size & shape
Originals: find your everyday fit
Generally 54–60 cm
This is the general adult range for Originals. There are model-specific exceptions in the catalogue, so check the product page as well. Adjustable does not mean unlimited: a cap should fit without forcing the closure or pulling the crown out of shape.
A-frame describes the front profile, trucker describes mesh back panels and snapback describes a closure. Those labels do not establish a separate head size. A taller crown changes the silhouette; it does not automatically mean a wider fit.
Explore the collection →
Size & shape
Kids: measure first, choose M or L
M 45–49 · L 49–54 cm
Choose by head circumference, not age. Kids M fits 45–49 cm and L fits 49–54 cm. At 49 cm, also compare crown fit and comfortable closure adjustment.
The cap should stay secure without pressure or slipping over the eyes. Do not buy an oversized cap solely for growing room.
Explore the collection →
Two caps. One shared look.
What is in a Family set?
1 Originals + 1 Kids cap
Every Family set pairs one adult Originals cap with one kids cap. Select M or L for the child. The adult cap uses the size range of its Originals model.
Measure both wearers separately. The shared design brings the look together; each cap still needs to fit its wearer comfortably.
Explore this matching set →Build your matching fit
Adult Originals
54–60 cmEssentials · Light blue / Brown
BS-CAP-215
Matching Kids cap · L
49–54 cmEssentials · Light blue / Brown
BS-CAP-215-L
This example shows the matching Essentials set with kids size L. Kids size M (45–49 cm) is also available. Measure each wearer separately.
Size & shape
Bucket hats: a different kind of fit
54–59 cm fit guideline
Our bucket-hat size chart uses a nominal size of 59 cm and a fit guideline of approximately 54–59 cm. A bucket hat has no snapback adjustment. Expect the feel to be looser toward the lower end of that range; the label is not a promise of the same snugness on every head.
If you need a close, adjustable fit, compare a cap with a closure. Do not choose a bucket hat smaller than your head measurement in the hope that it will stretch.
Explore the collection →Circumference is only part of the fit
Crown height
Compare front and side views. More height changes the silhouette; it does not automatically mean a wider fit.
Adjustment
Use the closure for a secure fit within the stated range. Do not force a cap that feels too small.
Comfort
Wear it in your normal position. Check for pressure, sliding over the eyes or constant readjustment.
How do I convert centimetres to inches?
Divide centimetres by 2.54. For example, 54 cm is approximately 21.26 inches. Use centimetres when comparing the ranges in this guide.
Does one size mean every head?
No. It means one offered size or adjustment range. Pro is approximately 55–61 cm, adult Originals generally 54–60 cm with model-specific exceptions, and kids caps have separate M and L ranges.
Can I use the adult chart for my child?
Use the kids chart for kids caps. A small adult circumference does not guarantee that the adult crown and proportions will sit comfortably on a child.
Need help choosing?
Contact our team with the model name and your head measurement. For style differences, return to the Cap Guide.
Why can two caps with the same size range feel different?
The circumference range describes the adjustable fit around the head. Crown height, structure, panel construction, sweatband and brim shape also affect how a cap sits. A soft Aero can feel different from a structured Flow at the same head measurement. If a cap feels too tall or presses in the wrong place, tightening it is not always the solution; compare a different shape.
What if my measurement is between the listed sizes?
Measure again with the tape level and comfortable against your bare head. For adjustable caps, choose a range that includes your measurement. Kids M and L meet at 49 cm, so also consider how the crown sits and whether the closure can hold comfortably. Bucket hats have no snap adjustment. Do not choose a size below your measurement expecting the fabric to stretch.