Helmet Sizing Guide: Measure and Fit Charts

Why Helmet Fit Matters

A ballistic helmet protects only where it touches the head. A shell that is too large shifts forward over the eyes under movement; a shell that is too small sits high, leaves the temples open and turns a patrol into a headache. Fit is not a comfort detail — it is part of the protection system.

Helmet sizing is simpler than body armor sizing: a helmet fits a static measurement, head circumference. Measure it once, choose the shell size, tune the interior pads, and one model fits a full roster. This guide covers measurement, the size charts used across MICHH, ACH and FAST helmets, and bulk planning. Shell profiles change coverage — see our high cut vs mid cut guide.

How to Measure Head Size

Head circumference is the only measurement a helmet size chart needs:

1. Wrap a flexible tape measure around the head, about one inch — roughly 2.5 centimeters — above the eyebrows, passing over the largest part of the back of the skull

2. Keep the tape level all the way around, not tilted at the back or dipping at the front

3. Pull the tape snug but not tight — it should touch the hair without compressing it

4. Read the measurement in centimeters, and take it twice to confirm

One inch equals 2.54 centimeters, so a head of 58 centimeters measures about 22.8 inches. For bulk programs, have the issuing officer use the same tape position and tension for everyone, or the size data will be unreliable.

Ballistic Helmet Size Charts

Most MICH, ACH and FAST style helmets use the same four-size convention keyed to head circumference. The table shows the reference ranges used across the industry:

Treat these as reference values, not gospel — manufacturers each publish their own table and boundaries drift by a centimeter either way, so always confirm against the size chart of the exact model you order. Our MICH full cut helmet, FAST high cut helmet and other ballistic helmets ship with model-specific charts. Because size names map to similar ranges across MICH, ACH and FAST profiles, a unit can standardize on one shell size for most of its roster — the ballistic helmet guide covers the category behind those charts.

Pad Systems and Fit Adjustment

The shell size gets the helmet close; the pad system makes it exact. Ballistic helmets fit through replaceable foam pads — crown pads over the top and comfort pads around the sides and rear — in thicknesses from roughly 10 to 25 millimeters.

Fit tuning is a process of elimination. Start with the pads your circumference suggests, seat the helmet level with the front edge a finger-width above the eyebrows, and test. The shell should not slide when the head shakes, press hard at any point, or shift with the chin strap unhooked. If it wobbles, fit thicker side pads; if it pinches, swap the crown pads or try the next size. Spare pad sets let armorers fit new personnel on issue day.

The chin strap finishes the job. A four-point retention strap with an occipital cup holds the shell down; two fingers should fit under the strap at the throat, no looser. Fit night vision users with the device and counterweight attached — the balance changes how the shell sits.

Sizing for Bulk Orders

Institutional orders need a size mix, not a single size. For a roster of 100 wearers, this distribution is a workable reference based on how issued helmets sell across military and police programs:

The ratio shifts with the population: units with many smaller personnel need more S shells; large-frame units push toward L and XL. Measurement data beats averages — record real circumferences and the factory tunes the mix precisely. Whatever the mix, add spare pad sets in every thickness so shells are tuned rather than exchanged, plus a buffer of M and L, the sizes reordered first.

What to Check Before You Order

Wholesale Sourcing Checklist

1. Collect roster measurements — real head circumferences where possible; otherwise plan with the reference mix

2. Confirm the model size chart — request the exact cm ranges and pad thickness options in writing

3. Specify pad kits — order spare pads in all thicknesses alongside the shells

4. Request samples within 5-7 days — test each shell size with the gear the unit actually wears

5. Plan the distribution — agree the S/M/L/XL ratio per 100 pcs before mass production

6. Confirm MOQ and lead time — standard order 100 pcs, trial order 50 pcs, bulk delivery 20-30 days

FAQ

How do I know my helmet size?

Measure head circumference one inch above the eyebrows and match it to the size chart of the specific model. A 55-58 cm head falls in size M on most charts.

What if I am between sizes?

Choose the larger shell and tune with thicker pads. A slightly large shell with proper padding fits better than a small shell that cannot be adjusted outward.

Do MICH, ACH and FAST helmets use the same sizes?

The size names and ranges are similar across all three profiles — S through XL keyed to head circumference — but boundaries drift between manufacturers, so check the model-specific chart.

How should a helmet fit once adjusted?

Level on the head, front edge about a finger-width above the eyebrows, no sliding when the head shakes, no single pressure point, and the chin strap snug but not tight.

What size mix should an agency order for 100 people?

About 40 pcs in M, 30 in L, 20 in S and 10 in XL as a reference start, adjusted with real measurements when available and backed by spare pad kits.

Final Word

Fit is the cheapest performance upgrade a unit can make. A correctly sized and padded helmet protects as rated, stays comfortable through long operations and accepts the night vision and communications gear the mission demands — all from one careful measurement and a box of spare pads. The sizing rules here apply across the whole category, from full cut MICH shells to high cut FAST helmets.

Our factory supplies ballistic helmets with model-specific size charts, full pad kit options and OEM support for bulk agency orders. Send your roster size data or head-size distribution — we will configure the mix and quote the order.