Best Bike Helmet for Small Heads: Which One to Buy

Adults with a small head, roughly 50 to 54 centimeters around, should look first at brands whose small size reaches down to 50 centimeters, such as Kask and POC, then at Giro and Smith small sizes that start at 51 centimeters, and only then at youth models for very small heads. Which helmet is best matters less than whether the size range actually covers your measurement, so measuring your head comes before choosing a brand.

Start with the tape measure

Helmet sizing is not standardized. A 54 centimeter head is a Small in Giro and Kask, but sits in a Medium range with some other makers. To measure, wrap a soft tape around the widest part of the head, about 2.5 centimeters above the eyebrows and above the ears. Write down the number and compare it with each maker’s chart rather than with a shirt-style S, M, or L.

Small heads come with a second problem: shape. A helmet with the right circumference can still sit too high, too far back, or press on the temples if it is the wrong shape. Reviewers who write about small and narrow heads often mention a helmet that feels roomy at the sides but shallow, or one with a retention dial that runs out of adjustment before the shell feels snug.

At a glance: sizes that reach small heads

Sizes above come from the makers’ size charts and from retail and review round-ups. Charts change and some were secondhand, so confirm the figure on the maker’s current chart before you buy.

Adult helmets that reach down

Kask and POC

If your head is near 50 centimeters, Kask and POC are the best-documented places to start because their Small sizes are listed from 50 centimeters. The Kask Utopia Y is an aero design that Cyclingnews measured at 264 grams in medium and ranked 12th in its wind-tunnel test, saving 6.37 watts. BikeRadar notes it lacks MIPS and criticizes its fit mechanism, so a rider with a small head should check the fit in person.

Giro

Giro’s adult Small is listed at 51 to 55 centimeters, and some race models offer an XS near 52 to 53.5 centimeters. The brand’s universal-fit women’s helmets cover 50 to 57 centimeters. The Aries Spherical, sold in S, M, and L, uses MIPS Spherical and is praised for ventilation, with GearJunkie rating airflow 9.3 out of 10 across 24 vents. A comparison by Two Wheel Tales describes its fit as sleek and stable, which is helpful for smaller or narrower heads.

Specialized

The Prevail 3 is sold in S, M, and L, and Bikerumor says it ventilates better than any helmet it has assessed. The same comparison finds it comfortable for wider heads but less secure on narrow heads, which matters if your small head is also narrow.

Smith and Bontrager

The Smith Convoy MIPS Small is listed at 51 to 55 centimeters. Bontrager is more confusing, because retail listings show differing ranges for the same Small and no official chart appeared in the reviews and size guides consulted; Starvos helmets are noted as available in Extra Small. Use the current maker chart.

When a youth helmet makes sense

Some adults and teens sit below even the smallest adult sizes. Youth helmets such as the Giro Scamp II and Smith Sidekick Jr. cover about 45 to 55 centimeters. Reviewers say the Scamp II is shallower than many helmets, so it sits higher on the forehead, and that children or adults with small but tall heads may need a deeper shell. Youth helmets also have lower-profile graphics. They are certified to the same type of standard as adult helmets, but check that the label states the standard that applies where you ride.

Fit and safety notes

• Level and low. The front edge should sit about two finger widths above the eyebrows, not tilted back on the forehead.
• Side straps. They should form a V just below each ear. Adjust the sliders before you tighten the chin strap.
• Chin strap. You should fit one finger between strap and chin, no more.
• Dial range. If the retention dial is almost fully tightened, the helmet is too big, so try a smaller size or a different brand.
• MIPS and padding. A MIPS liner takes a little internal space, so a MIPS version can feel slightly snugger than the non-MIPS model in the same size.
• Replacement. Replace after any significant impact and follow the manual’s age guidance.

If a headache or pressure point persists, or if you have a medical condition affecting the head, talk to a doctor or a qualified bike-shop fitter.

Pick X if…

Budget tiers in plain terms

Budget helmets come in universal fit with an adjustable ring and sometimes a single small size that may still be too big. Mid-range helmets from Giro, Smith, and Bontrager add more size options and rotational protection on many models. Premium models such as the Aries Spherical and Kask road helmets add refined ventilation and fit systems. For a small head, the number of size steps matters more than price.

Alternatives to consider

• Mountain-bike helmets with a Junior or XS size. One roundup lists the Leatt MTB Enduro 2.0 in Junior XS at 50 to 54 centimeters and the Demon United Podium X MIPS suiting 51 to 55 centimeters.
• Add-on fit pads. Some makers sell extra padding sets, but only use ones the helmet maker approves.
• Try before you buy. A local shop with several brands can save several returns.

Trying helmets on without wasting time

When you visit a shop, start with the size your tape measure suggests, then try one size either side. Put the helmet on, tighten the dial, and fasten the strap. Shake your head side to side and nod; the helmet should move with your skin and not slide. Leave it on for several minutes, because pressure points on the forehead and temples tend to show up late. If you order online, choose a retailer that accepts returns, keep the tags and packaging, and check that the helmet you receive carries the safety certification label you need for your region. For very small heads, it also helps to compare models from at least two brands, since the difference between a good and a poor fit is often shape rather than the number on the sticker.

Frequently Asked Questions

What size bike helmet fits a small head?

Measure your head circumference and match it to the maker’s chart. Small sizes often cover about 50 to 56 centimeters, though the exact range differs between brands.

Which brands go smallest for adults?

Kask and POC list Small sizes starting at 50 centimeters, according to a size-chart round-up. Giro and Smith Small sizes begin at 51 centimeters.

Is it safe to use a kids’ helmet when you are fully grown?

If it fits and carries the correct safety label, yes in principle, but kids’ helmets are often shallower and may not suit every adult head. Check the shape and the standard on the label.

Does MIPS change the size I should buy?

The size stays the same, but the liner uses a little space, so the MIPS version can feel snugger. Try it on if you are between sizes.

My helmet wobbles even when tightened. What should I do?

Try a smaller size or a different brand, because the shape may not match your head. A shop fitter can help adjust the straps and pads.

Can I add pads to make a big helmet fit?

Only use pads the helmet maker supplies or approves. Third-party padding can change how the helmet performs in a crash.