Why does an i-Size orange label show height and a kg limit?

Why print centimetres and kilograms on the same sticker?

nidirect is the official Northern Ireland explainer and it states the split plainly: Regulation 129 (i-Size) seats are based on height or length and have a maximum weight. The label tells you the maximum height or length the seat is designed for. You still need the child's weight because the same label shows the weight cap.

The Baby Products Association says the same in Great Britain trade language: R129 seats are chosen by height, and an upper weight limit is also given for ISOFIX seats. GOV.UK tells you to check a height-based seat is suitable for the child's height. It does not delete the kilogram line the maker printed.

What is the cm range doing, and what is the kg figure doing?

Official records show both numbers as limits of the approval. The centimetre line does not override the kilogram line. The kilogram line does not turn the seat into an R44 group seat.

Which number wins if my child hits one limit first?

The first printed limit the child reaches ends that approval range. A tall, light child can pass the upper centimetre figure while still under the kilogram cap. A heavier child can reach the kilogram cap while still inside the centimetre range. nidirect tells you to check the label for length or height and to observe the maximum weight.

Which? describes the same two clocks in consumer language: R129 categories are based on height measurements, and the orange label is where you read them; weight is how the older R44 groups are built. On an i-Size sticker those two systems sit together, so you measure and weigh.

• Still inside both printed figures — the child is inside the approval range on the sticker.
• Over the cm figure, under the kg figure — the height approval has ended.
• Under the cm figure, over the kg figure — the weight cap has ended.
• Head above the shell — Which? treats that as a separate outgrown sign, not a replacement for the printed numbers.

How do I read both numbers on one orange label?

1. 1
   Find the stature line Copy the centimetre range exactly (for example 61–105 cm). That is the height or length the Regulation 129 approval covers.
2. 2
   Find the kilogram line Copy the maximum weight, and any minimum weight if it is printed. nidirect says each maker specifies the length or height range and the maximum child weight for that product.
3. 3
   Measure stature the way the instructions describe Which? describes a crown-to-heel measure for babies. For older children, stand them against a wall. Use centimetres, not clothing age.
4. 4
   Weigh the child Use kilograms. The kg figure is not an estimate and it is not cancelled because the child still 'looks' inside the seat.
5. 5
   Stop at the first printed limit If either number is outside the sticker, that approval range has ended. Do not average the two figures.

Does a kg figure mean the seat is really an R44 group seat?

No. GOV.UK keeps the marks separate: height-based seats show R129; weight-based seats show ECE R44 and the group table (0 / 0+ / 1 / 2 / 3). A kilogram cap on an R129 sticker is an occupant limit on a height-based approval. It is not Group 1 printed in disguise.

Child Car Seats still tabulates R44 by weight and R129 (i-Size) by height. Shops sometimes keep talking in groups because parents know those numbers. The orange R129 mark remains a centimetre range plus a kg cap, not a group letter.

In shortCentimetres say who the seat is sized for. Kilograms cap how heavy that child may be. Both are printed limits. Neither is a verdict that the seat is or is not suitable beyond what the sticker states.

The law says 135 cm. Why does my booster label go to 150 cm?

GOV.UK says children normally use a child car seat until they are 12 years old or 135 centimetres tall, whichever comes first. That is the law on when a child restraint is required. Many R129 booster approvals are printed to 150 cm because that is the stature used in some other European rules and in the regulation's booster fixtures. The extra centimetres on the sticker do not change the UK 135 cm / 12-year rule.

Which? notes that difference when it explains i-Size child seats. For the orange label in your hand, still apply both the printed cm range and the printed kg cap. The 135 cm figure is the UK law line for using a child restraint at all, not a reason to ignore the kilogram number on an i-Size sticker.