Anyone know how do I install a convertible car seat with LATCH correctly?

Quick way to get it right every time. Open both manuals your car and your car seat to confirm which seating spots allow lower anchors and what the LATCH weight limits are. Set the seat to the correct recline for rear or forward facing and use the seat's level indicator if it has one. Attach the lower anchors, make sure the strap is flat, then press your body weight into the seat while pulling the LATCH strap tight. Check for movement only at the belt path and aim for under one inch side to side or front to back. If forward facing, always connect and snug the top tether. Use either LATCH or the seat belt, not both, and switch to a seat belt install once your child or the seat hits the stated LATCH weight limit. A quick check with a certified child passenger safety technician is worth it for peace of mind.

If you want something that makes LATCH especially straightforward, consider Clek Foonf. Its rigid LATCH for forward facing gives a near foolproof click-in install, and the built-in recline helps you dial in the proper angle. It is on the heavy side, but the rock-solid install and ease of use are excellent.

From a tech perspective the biggest pitfalls are wrong seating position for LATCH, missed top tether when forward facing, and ignoring weight limits and vehicle makers often cap LATCH use at a combined weight of seat plus child around the mid sixties and some child seats give a child weight limit for LATCH instead, so if you are not sure a conservative move is to switch to the seat belt install around a fortyish pound child — Set the recline correctly, route the strap through the proper belt path, click both anchors, then tighten while pushing down into the seat. Verify less than an inch of movement right at the path and you are done. Do not stack LATCH and the seat belt together, pick one system and use the top tether for forward facing only.

People get told LATCH is safer than the seat belt which is not true when both are used correctly. tbh Use the system that gives you the tightest install in a seating position your car allows and that stays within the weight limits for that system. Make sure the anchors you clip to are the actual lower anchors and not a cargo hook and don't try to use both LATCH and the belt at the same time. Less than an inch of movement at the belt path is the standard. You got this.

For a grandparent or sitter car, practice the steps at home until they are automatic set recline, attach both anchors, flatten the strap, lean in and tighten, then check only at the belt path, and always add the tether forward facing. If anyone is unsure, get a quick check from a certified child passenger safety technician since not every fire station has one available.

Find approved anchors and confirm weight limits, set the right recline and level, then clip both connectors, remove twists, press down, and tighten until movement at the belt path is under an inch.

Add the top tether when forward facing, and switch to a seat belt install if LATCH is loose or over its limit.

YEP been there.

Hmm, My routine is quick now. Put the seat in at the correct recline, snap on both lower anchors, pull the LATCH strap from inside the seat so I am pulling in line with the adjuster, then lean my body weight into it while tightening. Do the inch test at the belt path, not the headrest. If I fight it for more than a minute I switch to a seat belt install because sometimes the angle of the anchors in a particular car does not play nice. Either method is safe when tight. Done.

Some cars have sloped or cushy seats that fight you. Try reclining the vehicle seatback a few clicks before you tighten the LATCH, get the strap fully snug while pushing down, then bring the seatback upright again and that often takes out the last bit of slack. Keep the LATCH webbing flat with no twists and make sure you are not accidentally sitting on the adjuster. No aftermarket add ons or strap extenders since those are not crash tested with your seat. One inch or less of movement at the belt path is your pass fail.

Double check whether your center spot actually allows LATCH. Many vehicles only allow it on the two outboard seats and do not permit borrowing the inner anchors for the middle unless both the vehicle and car seat say it is okay and the spacing matches the standard but then... if the center is not approved for LATCH, install with the seat belt there and that is fine. Set the recline first, use the level indicator, then attach lower anchors and pull the strap tight while compressing the cushion where the child sits. A rolled towel or pool noodle to help achieve the proper rear facing angle is sometimes allowed but only if your car seat manual says so which, yeah... one inch or less of movement at the belt path is the goal.

Ugh, Make sure you are threading the LATCH strap through the correct belt path for how the seat is facing. Convertible seats have one path for rear and a different one for forward and it is easy to use the wrong one when you flip it. Buckle both connectors to the vehicle anchors, remove twists in the webbing, then apply pressure straight down while pulling the adjuster. When forward facing connect the top tether and snug it. Check for wiggle at the belt path only and aim for under an inch. Simple but easy to miss.

I used to yank on the top of the seat and think it was tight then a tech showed me to test only at the belt path where the LATCH strap runs. Night and day. I click both connectors, then lift the cover or reach through the seat to pull the tail straight out from the adjuster while pushing down with my forearm. For forward facing I always add the top tether and snug it so the head does not pitch forward. If you are stuck after trying a few angles do not fight it forever, a seat belt install can be easier in some cars and is as safe when done right.