How to Install an Infant Car Seat, Step by Step

Before anything else: this page is a general orientation, not a substitute for your two manuals. Always follow the instructions that came with your specific car seat and your vehicle owner's manual, and have your install checked for free by a Child Passenger Safety Technician (CPST). Car seats and vehicles vary, so the exact steps for your combination live in those manuals. What follows are the universal principles that apply across seats — use them to understand the process, then defer to the manuals for the specifics.

A correctly installed seat protects far better than a loose one, and a large share of car seats are installed with at least one error. The good news is that getting it right is very learnable, and a free CPST check confirms it. Take your time; there is no rush.

First principles that never change

• Infant seats are rear-facing only. An infant car seat is always installed facing the rear of the vehicle. Never install one forward-facing.
• The back seat is the place for it. A rear-facing seat must never be installed in front of an active frontal airbag. Put it in the back seat.
• Use the belt OR lower LATCH anchors — never both at once.Pick one method to secure the base. Using both at the same time is not tested or approved unless your seat's manual specifically says so (almost none do).
• Read both manuals first. Your car seat manual and your vehicle manual together tell you where LATCH anchors are, which seating positions are approved, and any limits.

Step 1: Choose your seating position and method

Check your vehicle manual for where the lower LATCH anchors are located — they are not in every seating position, and the center seat often cannot borrow anchors from the outer seats. Decide whether you will install with the vehicle seat belt or with the lower LATCH anchors. Both are safe when done correctly; choose whichever gives you a tighter, easier install in your car. Note that LATCH has a combined weight limit (the seat plus the child), after which you must switch to the belt — your seat's manual states the number.

Step 2: Set the recline angle for a newborn

A newborn needs the correct recline so their head does not fall forward and restrict their airway. Most infant seats have a built-in angle indicator (a line or a bubble level) and often an adjustable foot or base to dial it in. Set the base so the indicator reads correctly on your seat — this is one of the most important and most missed steps. The manual shows exactly what "level" looks like for your seat.

Step 3: Install the base tightly

Whether you use the belt or LATCH, the goal is the same: the base should not move more than one inch side to side or front to back when you test it at the belt path.

• Route the belt or LATCH strap through the correct belt pathmarked on the base (rear-facing seats have a specific path — use it).
• Press down firmly with a hand or knee in the base while you pull the belt or LATCH strap tight, removing all the slack.
• Lock the seat beltif you used it — most vehicles lock the belt when you pull it all the way out and let it retract; your vehicle manual explains its locking method.
• Test at the belt path. Grip the base where the belt runs through and tug. Less than one inch of movement in any direction means it is tight enough. More than that, redo it tighter.

Step 4: Buckle the baby correctly

A perfect install still needs a correct harness. For a rear-facing infant:

• Harness straps at or just below the shoulders.For rear-facing, the slots should be at or slightly below your baby's shoulders. (Forward-facing is the opposite.)
• Snug harness — the pinch test. Tighten until you cannot pinch a horizontal fold of webbing at the shoulder between your fingers. Snug is safe; loose is not.
• Chest clip at armpit level. The chest clip sits flat at the level of the armpits, not on the belly and not up on the neck.
• No bulky coats under the harness. A thick coat leaves the harness too loose in a crash. Dress the baby thin and tuck a blanket over the buckled harness for warmth.

Step 5: Get it checked

Even careful parents miss things, so confirm your work with an expert. A certified CPST will check your install for free — NHTSA maintains a find-a-station tool, and many fire departments, hospitals, and health departments host regular check events. This is the single best way to be sure, and there is no charge.

If you use the carrier on a stroller

Many infant seats click onto a stroller as part of a travel system, which is a convenient way to move a sleeping baby — but the same seat still has to be installed correctly in the car every time. If you are choosing a bundle, our best travel systems roundup weighs each mainly on how good and how installable its infant seat is, and our best infant car seats roundup does the same for standalone seats.

Looking ahead

Your baby will use this rear-facing infant seat until they reach its weight or height limit, then move to a convertible seat — still rear-facing. Our guides on when to switch to a convertible car seat and rear-facing versus forward-facing cover what comes next. Through every stage, the same principle holds: follow your manuals, keep the install tight and the harness snug, and rear-facing as long as the seat allows.