Toy Choking Hazard Size Checker

Why the small parts cylinder exists

The “no-choke” test cylinder used in ASTM F963 (US) and EN 71 (EU) is designed to approximate the size of a young child’s fully expanded throat. If an object fits entirely inside the cylinder, it can lodge in a child’s airway. The cylinder was developed in the 1970s by the US Consumer Product Safety Commission after a sharp rise in choking-related infant deaths from small toy parts.

The CPSC’s small parts regulation (16 CFR 1501) was the first major US toy-safety regulation specifically focused on choking. It’s been incorporated into ASTM F963 and is now the de facto global standard, with EN 71 closely matching.

The test cylinder dimensions

• Diameter: 31.75 mm (1.25 inches)
• Depth: 57.15 mm (2.25 inches)
• Angled at 45 degrees to catch elongated objects (a long thin object can rotate as it falls in)

An object is classified as a “small part”, and therefore a choking hazard for under-3, if any portion of it fits entirely within the cylinder, even when compressed. This applies to soft toys, foam, plush that can be squished, and articulated parts that can rotate to fit.

The rule in plain language

A toy part is a small part (choking hazard) if all three are true:

1. Width/thickness ≤ 31.75 mm (so it fits the cylinder diameter)
2. Length ≤ 57.15 mm (so it fits the cylinder depth)
3. Not permanently attached to a larger non-removable part

A small marble (12 mm diameter, fits in cylinder) is a small part. A doll’s plastic hand attached to a 30 cm doll body is not a small part, even though the hand alone fits in the cylinder, because it is permanently attached. But if the hand can be pulled off with normal force, the hand becomes a small part.

Why this page’s answer errs toward “hazard”

The real test is physical: the part goes in the cylinder and you look for anything protruding. A calculator working from three numbers cannot reproduce that, so it screens on the smallest and largest dimensions and treats anything that clears both as a small part. For a rigid rectangular block that over-reports, because it is the diagonal of the two smaller faces that has to clear the 31.75 mm opening, not the smallest side on its own. A 30 × 30 × 50 mm block has a 42.4 mm diagonal and will not go in, but this page will still call it a hazard.

That direction is deliberate. On a screening tool for a child-safety question, an answer that is occasionally too cautious costs you a redesign; an answer that is occasionally too permissive costs a great deal more. Where the diagonal clears the opening, the page says so, and you can take that as the real answer for a rigid part. For anything soft, squashable, or hinged, ignore the diagonal entirely and take the cautious verdict, because a compressible part gets squeezed into the cylinder in the actual test.

Tested by the “tension test”

The cylinder is only the size test. There’s also a separation test: any part must withstand a 15 lbf (67 N) pull force for 10 seconds without separating. If a part can be pulled off and fits in the cylinder, the toy fails.

The implications:

• Glued-on eyes, hair, or accessories must survive the 15 lbf pull
• Snap-on parts must be tight enough not to pop off under normal play force
• Velcro and weak adhesives often fail this test
• Sewn-on parts (with secure stitching) typically pass

Balls and the small ball rule (separate stricter test)

Spherical objects have their own classification because they roll easily into a child’s airway:

The threshold is exactly 1.75 inches, which is 44.45 mm, and the rule is “less than”, so a ball measuring 44.4 mm is a small ball and one measuring 44.5 mm is not. That looks like hair-splitting until you are the one sourcing wooden balls in 44 mm and 45 mm, which is a real gap in the catalogues. A 44 mm ball is banned for under-3 toys and needs a warning label on anything else, even though it does not come close to fitting inside the small parts cylinder. The extra margin exists because a sphere seals an airway in a way an irregular object does not.

Age labeling, and the exact words

If your toy contains any small parts (per the rules above), it must be labeled for ages 3 and up. The required warning is prescribed wording, not a paraphrase:

WARNING: CHOKING HAZARD - Small parts. Not for children under 3 yrs.

Dropping “Small parts”, or writing “not suitable for” instead of “not for”, is a labeling defect in its own right. Copy the sentence exactly.

The label must be:

• Conspicuous on the packaging
• Visible at point of sale (not hidden inside)
• In English (and Spanish in some retailers)
• Permanent on the toy itself if sold without packaging

Failure to label is a CPSC violation. Civil penalties run to six figures per violation and the ceiling is adjusted for inflation every year, so look up the current figure rather than trusting any number printed on a web page, including this one.

What’s exempt from the small parts rule

Certain categories are explicitly exempt or have specific allowances:

• Books with cardboard pages, whose pages don’t count as small parts
• Modeling clay and dough, which come as naturally large lumps
• Toy musical instruments with hard-to-remove components
• Crayons and chalk, even though they fit the cylinder
• Latex balloons (uninflated), but with the specific balloon warning required
• Toys with batteries in a secured compartment, where the compartment must require tools to open

Where small parts actually fail in the lab

When safety testing labs evaluate toys, the typical failures:

The six-step bench review

Before sending a toy for commercial production, run this yourself:

1. Pick up the toy and try to pull off every component with reasonable force
2. Drop the toy on a hard floor from 3 feet and see what comes loose
3. Wash the toy or expose it to humidity for 24 hours. Does the adhesive weaken?
4. Bend, twist, and compress any soft parts. Do they hide a small part underneath?
5. Apply 15 lbf force to every glued/sewn/snapped component for 10 seconds
6. Measure every potential small part against a 31.75 × 57.15 mm cylinder

A 35 mm film canister gets passed around as a substitute cylinder, and it is worth being careful about. Its opening runs a little wider than 31.75 mm, so it swallows parts a real cylinder would reject. As a screening prop it errs in the wrong direction: everything that jams in a film canister is definitely a small part, but plenty of small parts drop straight through it. Treat it as a way to catch obvious failures, never as a way to clear a part. A proper test cylinder costs $30 to $50 and there is no reason to improvise once you are selling.

Magnets, a separate and more dangerous category

Small high-powered magnets (rare earth, NdFeB) have their own much stricter regulations after multiple deaths from children swallowing multiple magnets that then pinched intestinal walls. The regulations:

• Magnets accessible to children under 14 are restricted by flux index
• Sets of small magnetic balls (Buckyballs and similar) are effectively banned for children’s toys
• Magnetic toy components must either be too large to swallow OR too weak to attract through tissue

If your toy contains rare-earth magnets, consult the CPSC magnet regulations specifically, because the small-parts rule alone doesn’t cover the additional magnetic hazard.

The commercial reality

For a handmade Etsy seller making 100 toys/year, formal lab testing is overkill but the safety rules still apply. For commercial production (1,000+ units), expect:

1. Third-party CPSC testing at a registered lab, $500 to $2,000 per toy
2. CPSC product registration before sale
3. Tracking labels on each unit (required for children’s products)
4. Children’s Product Certificate (CPC), your own attestation of compliance

The legal liability for a child injured by a non-compliant toy is severe. Even non-commercial gift-giving can result in lawsuits if a child is hurt.

Bottom line

If any part of your toy fits in a 31.75 × 57.15 mm cylinder and isn’t permanently attached, the toy is for ages 3+ only, and the warning label is required. For children under 3, every component must be either too large for the cylinder or permanently attached with 15+ lbf pull strength. When in doubt, design conservatively. The safety margin is cheap and injury liability is not.