How to Measure Your Head for a Perfect Helmet Fit
Nine times out of ten, when a customer tells us a helmet "doesn't fit right," the problem isn't the helmet — it's the measurement it was built from. A tape measure held too loose, a reading taken above the brow instead of at it, or a size chosen by comparing to a baseball cap rather than actual centimeters. Since every HELMFORGE piece is cast and finished to order, getting this step right is the single biggest factor in whether your helmet feels perfect or merely "close enough."
Here's the exact method our workshop walks every custom-order customer through, whether you're outfitting for airsoft, a con deadline, or a display piece.
What You'll Need
- A soft fabric or vinyl tape measure (not a rigid metal one)
- A mirror, or a second person to help
- Any hairstyle you'd actually wear under the helmet — tie it back the way you normally would
Step 1: Head Circumference
Wrap the tape around your head about 1–1.5cm above your eyebrows and ears — this is the widest, most stable point on most skulls. Keep the tape level all the way around (check the mirror, or have someone confirm from the side). It should sit snugly, the way a fitted cap would, without compressing your hair.
Record the number in centimeters, not inches — even if you're ordering from the US or UK. Our sizing (and most European and Asian manufacturers') runs in cm, and converting later is where rounding errors creep in.
Step 2: Head Shape (Oval vs. Round)
Circumference alone doesn't guarantee fit — head shape matters for helmets with a tighter internal profile, like our Scout CQB or any close-cut cosplay build. Looking straight down at your own head from above (or a photo taken from above), most people fall into one of two broad shapes:
- Oval — noticeably longer front-to-back than side-to-side. The majority of heads fall here.
- Round — front-to-back and side-to-side measurements are close to equal.
If you're between our standard sizes or know you have a rounder head shape, choose "Custom — enter cm" at checkout on any product page and add a note. We adjust the internal liner shape accordingly at no extra cost.
Step 3: Crown Depth (for full-coverage builds)
For helmets that fully enclose the head — most of our fantasy and sci-fi replica builds — we also ask for crown depth: measure from the top of your head straight down to where you want the helmet's bottom edge to sit (usually just above the ears, or at the jawline for full-face designs). This prevents a helmet that's correctly wide but sits too high or too low.
Matching Your Measurement to a Size
| Size | Circumference | Best For |
|---|---|---|
| S | 54–56cm | Smaller adult heads, some teens |
| M | 57–59cm | Most adults — our most-ordered size |
| L | 60–62cm | Larger heads, thicker hair/hairstyles |
| Custom | Any | Anything outside 54–62cm, or a rounder head shape |
What Happens If It Still Doesn't Fit?
It happens — heads are complicated, and remote measuring has a margin of error even when you do everything right. That's exactly why every HELMFORGE order ships with a 30-day fit guarantee: tell us within 30 days of delivery and we'll remake the piece to corrected measurements or refund you in full, no return shipping cost on our error.
This sizing method carries over to our upcoming armor and prop lines too — the same 3-point approach works for chest rigs and full-face props.