Wisconsin’s child passenger safety law sets specific age, weight, and height thresholds for car seats and boosters. This guide lays out the current requirements as published by the official Wisconsin Legislature, plus penalties, front-seat rules, and answers to the questions parents ask most.
Law data last verified against official state sources: October 4, 2026.
Quick answer
Wisconsin requires rear-facing under 1 or 20 lbs, forward-facing for ages 1–4 (or under 40 lbs), a booster for ages 4–8 (40–80 lbs, up to 57 in), with harnessed seats in the back seat. Fines: $30–$75 (under 4).
Wisconsin car seat requirements by age and size
| Stage | What Wisconsin law requires |
|---|---|
| Rear-facing | Children under 1 year old or weighing less than 20 lbs — rear-facing child safety seat in the back seat if the vehicle has one. |
| Forward-facing | Children at least 1 year old and at least 20 lbs, but under 4 years old or under 40 lbs — forward-facing child safety seat in the back seat if the vehicle has one. |
| Booster seat | Children at least 4 but under 8 years old, weighing 40–80 lbs and no more than 57 inches tall — child booster seat. |
| Seat belt only | Age 8. |
Fines and penalties in Wisconsin
Fine: Child under 4: forfeiture of $30–$75 (waived with proof a compliant system was purchased/leased and installed within 30 days); child ages 4–7: $10–$25 first offense, $25–$200 for a 2nd/subsequent conviction within 3 years (Wis. Stat. § 347.50).
Front seat rules in Wisconsin
Front-seat rule: Rear-facing and forward-facing harnessed seats must be in the back seat if the vehicle is equipped with one.
The official law
- Statute: Wis. Stat. §§ 347.48(4)(am), 347.50
- Official source: Wisconsin Legislature
Wisconsin car seat law FAQs
What is the fine for a car seat violation in Wisconsin?
Fine: Child under 4: forfeiture of $30–$75 (waived with proof a compliant system was purchased/leased and installed within 30 days); child ages 4–7: $10–$25 first offense, $25–$200 for a 2nd/subsequent conviction within 3 years (Wis. Stat. § 347.50).
When can my child stop using a booster seat in Wisconsin?
Children at least 4 but under 8 years old, weighing 40–80 lbs and no more than 57 inches tall — child booster seat. Age 8.
Does Wisconsin law require rear-facing car seats?
Children under 1 year old or weighing less than 20 lbs — rear-facing child safety seat in the back seat if the vehicle has one.
Can my child ride in the front seat in Wisconsin?
Front-seat rule: Rear-facing and forward-facing harnessed seats must be in the back seat if the vehicle is equipped with one.
Where can I read the official Wisconsin car seat law?
Statute: Wis. Stat. §§ 347.48(4)(am), 347.50 Official source: Wisconsin Legislature.
Check another state
Driving across state lines? Requirements change at the border — use our interactive car seat law checker to look up any state by your child’s age, weight, and height.
Related state guides:
This page is for general informational purposes only and is not legal advice. Child passenger safety laws change — always verify current requirements with your state’s DMV, highway safety office, or the official statute linked below before making decisions.