Best Twin Car Seats by Car Size

The best twin car seat is the one that fits the back row of the car you actually own. Most car seat reviews skip this entirely. They list features, weight limits, and side-impact ratings, but they don't tell you whether two seats plus a third (for a sibling, a grandparent, or just an adult) will physically fit in your car.

Here's how to do that calculation in three minutes, then a list of seats that work in small, medium, and large cars.

Measure your back row in three minutes

You need three numbers:

• Total back-seat width, door to door, in inches.
• Width of each car seat at its widest point (usually the cup holder or shoulder area).
• Whether your car has LATCH anchors on all three back-seat positions, or only the outboard two.

Measure the back seat with a tape measure, then check car seat widths in any retailer's spec sheet. If 2x seat width plus 12 inches (for an adult between them, or a third child seat) exceeds your back-seat width, you can fit two seats but not three. If 2x seat width alone exceeds your back-seat width, you can't fit two abreast and you need a different seat or a different car.

Narrow seats that fit small cars

Compact sedans (Honda Civic, Toyota Corolla, VW Golf) have around 50 to 52 inches of back-seat width. To fit three across (two infants plus a third passenger), you need narrow seats around 16 to 17 inches wide.

• Diono Radian 3R / 3RX. Around 17 inches wide. Designed specifically for three-across fit. Heavier than average.
• Clek Fllo. Around 17 inches wide. Premium price, premium fit. Three-across in many small sedans.
• Graco SlimFit. Around 16.7 inches wide. Mid-priced. Good narrow-fit option.
• Cybex Sirona S. Around 17 inches wide. Premium European brand, good for narrow fit.
• Combi Coccoro. Around 15.5 inches wide. The narrowest option on this list. Lower weight limit.

Standard seats that fit most SUVs

Compact SUVs (Honda CR-V, Toyota RAV4, Subaru Outback) have around 56 to 58 inches of back-seat width. Two standard infant seats fit comfortably, with room for a third child seat or an adult. You can use the popular full-size options:

• Graco SnugRide SnugLock 35 / 35 LX. Standard, well-priced, widely stocked.
• Chicco KeyFit 35. Strong fit and easy install. The default for many twin parents.
• Britax B-Safe Gen2. Mid-priced, good safety record.
• UPPAbaby MESA. Premium, integrates with the Vista stroller.
• Nuna PIPA RX. Premium, lightest infant seat in this group.

When you actually need a bigger car

If you have one car and it's a compact, you may genuinely need to upgrade for the toddler years. Two narrow infant seats fit most compacts. Two convertible seats (the next stage, around 18 to 20 months) often don't, especially if you also have a third child or want to fit a passenger in the back.

If you're inside the first year, the narrow infant seats above will hold. After that, you'll either need narrow convertibles (Diono Radian still works) or a vehicle with a 58+ inch back row.

What we'd do

Measure first, shop second. If you have a compact sedan, default to the Diono Radian or Graco SlimFit. If you have an SUV, default to the Chicco KeyFit 35 or Graco SnugRide. Skip premium brands unless they meaningfully solve your fit problem. Two well-installed mid-tier seats outperform two expensive seats with mediocre installation.

Related reading

• Do I need a bigger car for twins?
• Decision: do I need two car seats?
• Build a personalized twin registry