What is the difference between the i-Size logo on the car and i-Size on the seat label?

What does the i-Size logo next to the car’s ISOFIX points mean?

On the car, i-Size is a seating-position class, not a second child-seat law. Silver Cross’s car-seat technicians describe it as the vehicle’s ISOFIX being approved as i-Size. You find that in two places:

• A pictogram on or near the ISOFIX bars, where the seat cushion meets the backrest.
• The vehicle handbook child-restraint or ISOFIX pages, which list which outer (and, rarely, middle) positions are i-Size.

nidirect tells anyone choosing a Regulation 129 i-Size seat to check that the car has ISOFIX anchorage points and, if they are not sure, to check with the manufacturer. Which? says i-Size seats fit i-Size-certified cars and almost all vehicles with Isofix, and to check with the car maker for the position.

No i-Size pictogram does not by itself mean the car has no ISOFIX. Many cars have standard ISOFIX anchors without the i-Size seating-position mark. That is the case the fit list is for.

What does i-Size on the seat orange label mean?

On the seat, i-Size is a UN Regulation 129 category. GOV.UK says height-based seats used in the UK show a capital E in a circle and R129. The orange sticker then says what kind of R129 product it is.

Silver Cross also notes that R129 has two approval routes: i-Size and specific vehicle ISOFIX. The second route exists because some seats are larger, or belt-fitted, and therefore need a vehicle list. Both routes still show E + R129. Only the category word on the sticker changes.

How do I match the car mark to the seat mark?

1. 1
   Open the vehicle handbook Find the child-restraint or ISOFIX table. Note which seats are listed as i-Size, which are ISOFIX only, and whether a support leg is allowed over under-floor storage.
2. 2
   Look at the ISOFIX pictograms Peel back the cushion gap. Photograph any i-Size logo and any plain ISOFIX icon so you are not matching from memory.
3. 3
   Read the seat orange label category Copy the exact words: i-Size, i-Size booster seat, specific vehicle ISOFIX, specific vehicle booster seat, Universal Belted. That string is the seat’s category, not a repeat of the car logo.
4. 4
   If both say i-Size Silver Cross’s published rule is that an i-Size seat and i-Size vehicle ISOFIX are treated as automatically compatible. Still fit the seat and check the handbook for airbags, front-seat use and support-leg limits.
5. 5
   If the car is standard ISOFIX only Do not stop. Open the seat maker’s vehicle list for that model. Silver Cross states you can still use an R129 i-Size seat on standard ISOFIX when the list includes that car.
6. 6
   If the seat says specific vehicle Ignore the wish that the car logo would be enough. That category requires the maker’s vehicle list, even if the car itself has an i-Size pictogram.

Can a car with standard ISOFIX and no i-Size logo take an i-Size seat?

Yes, when the seat manufacturer’s fit list includes that vehicle and seating position. That is the gap Which? leaves as “almost all vehicles with Isofix” and Silver Cross states in plain words: no logo is not a bar if the list allows the fit.

The reverse is also a label job. An i-Size logo on the car does not convert a specific-vehicle seat into a universal i-Size seat. The orange label category still governs the seat.

What if the seat says specific vehicle ISOFIX instead of i-Size?

Then the car pictogram is only a hint that ISOFIX exists. UN Regulation 129 defines specific vehicle ISOFIX as a category that is not claimed for every i-Size position. The handbook plus the maker’s list decide the match. nidirect still wants the label checked for the child’s height or weight and the seat used only as the maker instructs.

In shortThe car logo marks an i-Size seating position. The orange label marks the seat’s R129 category. Both i-Size is treated as a match. Standard ISOFIX without a logo can still take an i-Size seat if the fit list names that car. A specific-vehicle sticker always needs the list.