Wisconsin Car Seat Laws (2026): Ages, Booster & Penalty

Wisconsin requires a rear-facing seat until age 1 or 20 pounds, a forward-facing or continued rear-facing seat through age 3, and a booster seat through age 7 for a child who meets the weight and height bands, with any other child under 8 required to be restrained as provided in subds. 1. to 3. or in an approved safety belt, under Wis. Stat. § 347.48(4)(as). This page reflects the statute's text as of September 2026.

Jurisdiction scope: This article covers car seat and child-restraint law in the state of Wisconsin only. It does not address any other state. For other states, see the car seat laws hub.

Under 1 or under 20 pounds: rear-facing

Wisconsin's rear-facing requirement, in 347.48(4)(as)1., applies "if the child is less than one year old or weighs less than 20 pounds," whichever condition is true. It requires the child to be restrained "in a rear-facing child safety restraint system, positioned... in a back passenger seat of the vehicle if the vehicle is equipped with a back passenger seat."

Age 1 through 3, or 20 to 39 pounds: forward-facing or continued rear-facing

Once a child is at least 1 year old and weighs at least 20 pounds, but is still under 4 or weighs less than 40 pounds, 347.48(4)(as)2. allows either continuing with the rear-facing restraint from the stage above or switching to a forward-facing restraint system, again positioned in the back seat if the vehicle has one.

Age 4 through 7: the booster stage

The booster requirement in 347.48(4)(as)3. has three conditions that must all be true together: the child is at least 4 but under 8 years old, weighs at least 40 but not more than 80 pounds, and is not more than 57 inches tall. When all three apply, the child must be restrained as described in the forward-facing stage above or in a child booster seat. A child who exceeds any one of those thresholds, such as height, moves out of this specific stage, but not out of the restraint requirement itself; see the catch-all below.

Outside the three bands: the catch-all safety belt requirement

347.48(4)(as)4. closes the gap the first three subdivisions leave open. "Subject to subds. 1. to 3., if the child is less than 8 years old, the child shall be properly restrained as provided in subds. 1. to 3. or properly restrained in a safety belt approved by the department under sub. (2)." In practice, this means a child under 8 who does not fit the rear-facing, forward-facing, or booster bands, for instance a 6-year-old who already weighs more than 80 pounds or stands taller than 57 inches, is still required to be restrained, either under the earlier subdivisions or in an approved safety belt. There is no age or size at which a child under 8 falls out of Wisconsin's restraint scheme entirely.

Exemptions from Wisconsin's car seat law

Section 347.48(4)(c) excludes certain vehicle types from subsection (4): it "does not apply if the motor vehicle is a motor bus, school bus, taxicab, moped, motorcycle or is not required to be equipped with safety belts under sub. (1) or 49 CFR 571." A taxicab ride, for example, falls outside subsection (4).

Separately, section 347.48(4)(b) authorizes the department to exempt by rule a child who, because of a physical or medical condition or body size, cannot safely be placed in a child safety restraint system, child booster seat, or safety belt.

The back-seat rule only applies when there is a back seat

The back-seat placement language in both the rear-facing and forward-facing subsections is expressly conditional: it applies "if the vehicle is equipped with a back passenger seat." A vehicle without a back seat, such as some pickup trucks or two-seat vehicles, may legally have a properly restrained child in the front. The booster-stage subsection does not repeat this back-seat language.

Penalty for a car seat violation

A violation involving a child under 4, under 347.48(4)(am), carries a forfeiture, meaning a civil fine, of not less than $30 nor more than $75, under Wis. Stat. § 347.50(3). The statute also provides a way to avoid the forfeiture entirely: if the vehicle lacked a compliant restraint system at the time of the citation, the driver obtains proof of purchasing or installing a qualifying child safety restraint system within 30 days, and the driver has had no similar citation in the preceding 3 years, no forfeiture is assessed.

A separate forfeiture schedule applies to a child at least 4 and under 8, under section 347.50(4): not less than $10 nor more than $25 for a first offense, rising to not less than $25 nor more than $200 for a second or subsequent conviction within 3 years. The proof-of-purchase relief described above attaches only to the under-4 forfeiture in par. (a); subsection (4) has no equivalent waiver for the 4-to-under-8 band.

Leaving a child alone in a vehicle

Wisconsin does have an unattended-child statute, Wis. Stat. § 948.53, but it is scoped narrowly: it applies only to a child-care vehicle, meaning one owned or leased by a licensed child-care center, a certified family child-care provider, or a school-based program, and used to transport children to and from that provider. It does not reach private vehicles generally. This is a genuinely narrower rule than either "Wisconsin has no unattended-child law" or "Wisconsin bans leaving a child unattended generally," both of which would misstate it. A parent leaving a child alone in a personal vehicle is not covered by this specific statute.

Federal guidance vs. Wisconsin law

The federal standard that governs car seats as products, FMVSS 213 (49 CFR 571.213), regulates what a manufacturer may sell, not how a parent must use the seat; Wisconsin's own statute, described above, sets the use requirement, and its staged age-weight-height thresholds already track closely with NHTSA and the American Academy of Pediatrics' general rear-facing-then-forward-facing-then-booster progression. The AAP's separate recommendation to keep a child rear-facing "as long as possible," up to the seat's own limits, can extend longer than Wisconsin's own age-1/20-pound floor for switching to forward-facing; that's guidance layered on top of the statutory minimum, not a separate legal requirement.

Related Wisconsin traffic law pages

• Wisconsin DUI laws
• Wisconsin window tint laws
• Car seat laws in every state

Disclaimer: This article provides general legal information about Wisconsin's car seat law as of September 2026. It is not legal advice. Statutes, exemptions, and penalties change; verify the current text of the law before relying on it, and talk to a lawyer licensed in Wisconsin about a specific situation.

Statutes cited reflect their in-force version as of 2026-09-17. Last updated: 2026-09-17.

Frequently Asked Questions

Until what age does Wisconsin require a booster seat?

Wisconsin's booster stage covers a child who is at least 4 but under 8 years old, weighs 40 to 80 pounds, and is not more than 57 inches tall, under Wis. Stat. section 347.48(4)(as)3. All three conditions must apply together. A child under 8 who falls outside that band, for example by weight or height, must still be restrained under the catch-all in subd. 4., either as in the earlier stages or in an approved safety belt.

Can a child under 4 ride in the front seat in Wisconsin?

The back-seat requirement for the rear-facing and forward-facing stages applies only if the vehicle is equipped with a back passenger seat. A vehicle with no back seat may legally place a properly restrained child up front.

What is the penalty for a car seat violation in Wisconsin?

It depends on the child's age. For a child under 4, a violation carries a forfeiture of $30 to $75, under Wis. Stat. section 347.50(3); a driver can avoid it by showing proof of acquiring a qualifying restraint system within 30 days, if there's no similar citation in the prior 3 years. For a child at least 4 and under 8, section 347.50(4) sets a separate forfeiture of $10 to $25 for a first offense and $25 to $200 for a second or subsequent offense within 3 years, with no equivalent proof-of-purchase waiver.

Does Wisconsin have a law against leaving a child alone in a car?

Wisconsin's unattended-child statute, section 948.53, applies only to child-care vehicles, meaning one owned or leased by a licensed, certified, or school-based child-care provider, not to private vehicles generally. Wisconsin has no general statute covering a child left alone in a private vehicle.

Are taxis exempt from Wisconsin's car seat law?

Yes. Section 347.48(4)(c) exempts a motor bus, school bus, taxicab, moped, or motorcycle, and any vehicle not required to have safety belts installed, from the entire restraint scheme.