Convertible Car Seats

Convertible seats are so named because they convert: they are used first for rear facing children, then later they are turned forward facing. In recent years, the rear facing limits have increased substantially, so now most kids can stay rear facing until they are 18-24 month old, which is FAR safer than forward facing (see Extended Rear Facing benefits on CPSafety.com).

Top features to look for on a Convertible

5 point harness: Some convertibles come with a "tray shield", which acts as two of the 5 points of protection for a child. We recommend sticking with the 5 point models. The 5 point harness snugs in close to the child's body, conforming to a large range of sizes and shapes. Crash tests allow the child dummy's head to impact the shield, in some cases, but this is not recommended for children who wear glasses, and we would rather not have it happen to our children at all. So even though the 5 point harness takes a few extra seconds each time to use, that is what we highly recommend.
Five point harness: Little infant bodies are slumpy and wiggly. The 5 point harness does a better job than the older 3 point style of keeping the baby in the correct position, and allowing the harness to be nice and snug on the child's body.

Top Convertible Choices

Cheaper, basic seat: Graco Comfort Sport 5 pt.
This seat has the basics: a five point harness, rear facing to 30 pounds and a nice high seat back. The padding is fairly thin on the cheapest model, and the straps sometimes twist. The harness adjuster works OK, but takes some attention. The simplest versions usually retail for around $69. For an extra $10 you can get a thicker pad, and there are now versions up to $120 or so, sporting a thicker pad, leather trim, and perhaps a cup holder.
Middle price and featured seat: Evenflo Triumph
For a bit more money ($119-$129), you get eps foam (bike helmet foam) around your child's head, a Memory Harness that makes it easier to take the child in and out of the seat, a knob to tighten the harness, and a no-thread system for changing harness slots.
Most expensive and most features: Britax Roundabout
For several years, this seat has been the pinnacle of carseats. It is expensive (around $200), but it is packed with useful features, like eps foam; a full layer of comfort foam; a thick, washable, easy to remove pad in great colors; no-twist straps, a rear facing tether for added stability; a very smooth action harness (easy to adjust every single time you use the seat) and more. Parents love this seat and say that it was worth every penny. When it comes to LATCH, Britax has once again gone the extra mile, using mini-connectors with an adjuster on each side. This may have some significant crash benefits over a single sided latch strap, and are easier to use than the cheaper snap hooks.
Even better: Britax Marathon/Wizard
For about $249 you can get the Marathon, which has been called a "Super Roundabout". It is taller and wider and heavier. In this seat, children can stay rear facing until they are 33 pounds or until the top of the head is an inch from the top of the seat. Functionally, this means that children can stay rear facing longer in this seat than any other seat on the U.S. market today. Forward facing, this seat last longer than other convertibles too. The top harness slots are an inch or two higher than the Roundabout, and the weight limit is 65 pounds. I think that most kids will reach the top harness slots long before they reach the weight limit, but most kids can use this seat to a full 4-5 years old, when they'll be truly ready for a regular booster seat. So far, this seat fits great in cars, but rear facing in some small backseats, it will be a tight squeeze. The Wizard is similar to the Marathon, though more expensive, but includes a moving headrest piece, with some extra side impact protection. Some kids may feel too confined, but most seem to like this this seat.

Top Pick: Overall, this is our top pick for most children these days, because of how much longer the child can stay rear facing, and then forward facing in the harness.
Cosco Alpha Omega Elite and Safety 1st Intera
Both of these seats attempt to do it all, from birth through age 8 or so. Neither is a top pick for me, but many families like both seats. The Alpha Omega, also called the 3 in 1, has been around for a long time, and is quite popular. The newest version, the Elite, has addressed the biggest problem we had with the AO - now the top slots are higher and children are less likely to outgrow the harness portion before 40 pounds. The Intera is a new seat, but faces some difficulties for trying to be everything to every child. It is a large seat with a huge base. A baby, especially a newborn, is likely to swim in it. We tend to suggest a seat that specializes a bit more, but if you like the seat, give it a try. Just remember that it may not be the last seat you buy.