Estonishingly, two thirds of child car seats checked at fitting clinics are either wrong child car seat for that child or are fitted incorrectly. So it's essential that you buy the right one and you get it fitted properly to really protect your little one. Firstly, make sure you check the child car seat fits in your car before you buy. If it doesn't, then it may not protect your child in a crash. You'll also need to check it fits in any other cars you might use. Take a look at our buying video for more advice on how to choose the best. You should ask the retailer that you're buying the child car seat from to demonstrate the fitting for you and you should practice it yourself before you take it home. The safest place for the child car seat is always on the back seat of the car. All child car seats are fitted slightly differently, so make sure you read the instruction manual before you fit it. The base of the child car seat should sit squarely and evenly on the back seat of the car, but it doesn't that it's not right for the car and you'll need to get another one. Most of the time, the headrest should be raised to make sure it's not touching the seat. However, there are some child car seats that actually need it to be attached to the headrest, so check in the instructions before fitting. Fitting with icifix mountings allows you to simply click the seat base or seat into the car. They should have visual indicators that tell you it's securely in place, such as red markers that turn green, so check this for all the points each time you fit it. As well as the two rear mounting points, your seat will either have a foot that extends to the floor or a top tether that reaches behind the seat. If your seat has a foot, make sure it's fully extended, touching the floor and that there's no underfloor storage in the car as this could be a weak point in a crash. If you have a top tether, it must go over the back of the seat and clip into the dedicated mounting point in the boot without any obstruction. Make sure you don't use luggage hooks as these are not strong enough. We recommend testing the seat before you put your child in by pulling on the internal harness. Finally, you just want to make sure that your child's in the car seat properly, so you want to make sure the shoulder pads level with the shoulders or if they're raising up a little bit no more than an inch. Also, you want to make sure the harness isn't too tight or too loose, so you want to be able to get two fingers underneath the shoulder pads and then you want to take any thick clothing off because that really makes a difference to how well they're fitting in. You can find all our information on child car seats and best buys that have been able to withstand our tough lab tests that are higher than the UK standard by visiting witch.co.uk. Click on the links below for more on choosing a child car seat, how we test child car seats and a car seat reviews.