SeatCheck
LiveWhat child car seat does the law actually require, in every US state
Built by Caden Sorenson · Launched June 2026
What is SeatCheck?
SeatCheck answers one question, for every US state, with a citation: what child car seat, booster, or restraint does the law require? It exists because the honest answer is genuinely hard to find. The rules change at every state line, the official statutes are often buried or locked behind clunky portals, and most of what ranks online is ad-choked guesswork that blurs “the law” with “what a pediatrician recommends.”
It covers 56 jurisdictions: 50 states, DC, and five territories. For each one it shows the legal requirement and, separately, the American Academy of Pediatrics best-practice recommendation, so the two are never mistaken for each other.
How it works
You pick a state and enter your child’s age, height, and weight. SeatCheck returns the restraint the law requires there, rear-facing car seat, car seat or booster, or seat belt, and cites the exact statute. The same checker is published as an embeddable widget any site can iframe in.
Key Features
- All 56 US jurisdictions, each statute-sourced with its own last-verified date and source tier
- 84 state-vs-state comparison pages generated by a deterministic engine, so two pages differ exactly as much as the underlying law differs
- Law and recommendation kept separate, with the legal requirement as the floor and AAP guidance shown as best practice, never as a requirement
- Embeddable widget: no cookies, no accounts, self-contained CSS and JS, themeable by the host site and deep-linkable by URL parameters
- Provenance tooling: three lint scripts catch unsourced facts, internal contradictions, and dead source links so the data does not silently rot
Why it is built this way
SeatCheck is YMYL (you-your-money-or-your-life) child-safety content, which is why accuracy and provenance are prioritized over speed. Every threshold traces to the official statute, a statute that is silent on a value is recorded as null rather than filled with a reasonable guess, and the AAP recommendation is stored and displayed as a separate field so it can never be presented as law. A wrong car seat age is not a cosmetic bug, so the whole system is built to make a wrong number hard to ship.
Frequently Asked Questions
- You pick a state and enter your child's age, height, and weight, and it returns the restraint the law requires there: a rear-facing car seat, a car seat or booster, or a seat belt, with the exact statute cited. Alongside the legal answer it shows the AAP best-practice recommendation, which is usually stricter, clearly labeled as guidance rather than a legal requirement.
- All 56 US jurisdictions: 50 states, DC, and five territories. Every fact, ages, heights, fines, and citations, traces to the official statute and carries its own source URL, last-verified date, and source tier. Three lint scripts continuously check that nothing is unsourced, internally contradictory, or pointing at a dead link, and the data is refreshed against the official sources rather than secondary summaries.
- Yes. Besides the standalone site, SeatCheck ships an embeddable widget that parenting, gear-review, and family-travel sites can drop in via an iframe. It carries its own styling, sets no cookies, needs no accounts, detects the host theme, and resizes itself. You can pre-fill a state and accent color with URL parameters.
- No. It is a plain-language summary of the statutory requirement with the official citation so you can read the law yourself, plus the separate AAP best-practice guidance. It does not replace reading the statute or talking to a certified car seat technician.
What does SeatCheck tell a parent?
Which states does it cover, and how accurate is the data?
Can I add the car seat checker to my own site?
Is SeatCheck legal advice?
More about SeatCheck
- Behind the buildBuilding SeatCheck: A Car Seat Law Site Where a Wrong Number Could Hurt a KidOne of my kids wanted a booster seat, I didn't know if the law allowed it, and the answers online were terrible. So Claude and I built a cited car seat law site for all 56 US jurisdictions.
- From the blogBuilding Travel Vient: The Real Work Was Not Trusting ClaudeHow I built travelvient.com, a data-driven travel site with 80 airlines and a fleet of free tools, by letting Claude generate under skills I wrote and building the harness that catches it when it makes a fact up.
- From the blogBuilding a Travel Power Adapter Tool with Claude in a WeekendHow I turned leftover destination data into a 221-country power adapter finder with plug types and voltage comparison. The first version was unusable.
- From the blogBuilding a Layover Calculator That Knows Every Terminal at JFKHow I built a connection time calculator covering 70 airports with pairwise terminal transfers, customs buffers, and a five-factor assessment algorithm.