Tire load index calculator

What does 98H mean on a tire?

The two characters at the end are the service description. 98 is the load index: a number that stands for the heaviest load one tire can carry, 750 kg or 1,653 pounds for index 98 in the UN Regulation No. 30 table. H is the speed symbol, 210 km/h or about 130 mph. Both figures assume the tire is inflated to the pressure the maker specifies; the U.S. Tire Manufacturers Association (USTMA) notes that the maximum load printed on a sidewall goes with the maximum cold inflation pressure, for example 730 kg (1,609 lb) at 44 psi.

How do I read P225/60R17 98H?

P means a passenger car tire (a metric size). 225 is the section width in millimeters (8.86 inches). 60 is the aspect ratio: the sidewall is 60% of the width, 135 mm or 5.3 inches. R means radial construction. 17 is the wheel diameter in inches. 98H is the load index and speed symbol. The overall diameter is the wheel plus two sidewalls, 17 + 2 × 5.31 = 27.6 inches (702 mm). LT in front of the size marks a light truck tire, and a letter C after the wheel size marks a commercial (van) tire.

What load index do I need?

At least the one the vehicle came with. USTMA says never to choose a replacement tire with less load-carrying capacity than the original at the placard pressure, and Continental says you can go higher than the manufacturer’s index but never lower. Find it on the tire placard or certification label (usually on the driver’s door edge or door post), in the owner’s manual or on the original tires. The U.S. rule, FMVSS 110, sets the legal floor. On a passenger car the vehicle’s maximum load on a tire may not exceed the load rating marked on the sidewall. On an SUV, minivan, pickup, van, bus or trailer the load ratings of the tires on an axle must add up to at least the axle’s gross axle weight rating (GAWR), and a passenger car tire fitted there has its rating divided by 1.10 first.

What do XL, extra load and reinforced mean?

UN Regulation No. 30 calls a tire “reinforced” or “extra load” when its carcass is more resistant than that of the corresponding standard tire, and requires the words REINFORCED or EXTRA LOAD on it. Continental describes extra load (XL) tires as built to carry more weight than a standard tire of the same size, with higher inflation pressures. The load index printed on the tire already accounts for this, so read it as printed instead of assuming a standard-load number.

What do two load numbers like 121/118 mean?

Light truck and commercial tires show two load indexes: the first for single fitment, one tire per wheel position, and the second for dual fitment, two tires side by side at one wheel position. USTMA’s own example of a sidewall is LT245/75R16 120/116Q Load Range E, and it prints a separate maximum load for single and for dual use. The calculator shows both. Never mix passenger tires with light truck tires, including C-type commercial tires, on the same vehicle (USTMA).

What are the speed symbols?

A letter that stands for the highest speed the tire is rated for in laboratory tests: S is 180 km/h (112 mph), T 190 km/h (118 mph), H 210 km/h (130 mph), V 240 km/h (149 mph), W 270 km/h (168 mph) and Y 300 km/h (186 mph). The full list is in the table below. A speed rating is not a recommendation to drive that fast: USTMA says it does not apply to tires that are under-inflated, overloaded, worn or damaged. A letter in brackets after the load index, such as (96Y), marks a tire that can exceed 300 km/h; ask the maker for its limits.

Speed symbols

F to K come from UN Regulation No. 54, L to H appear in both Regulation No. 54 and No. 30, and V, W and Y come from Regulation No. 30. Miles per hour are the km/h figure divided by 1.609344, rounded; the USTMA table gives the same numbers for M through Y.

Load index 75 to 110

Kilograms are the values in UN Regulation No. 30, Annex IV; pounds are converted and rounded to the nearest pound, so a printed U.S. chart can differ by a pound. The calculator knows indexes 0 to 200 (Regulation No. 54 covers 121 to 200). To compare tire sizes and see the speedometer effect, use the tire size calculator; for how far a wheel sits in or out, the wheel offset calculator; for towing, the tongue weight calculator.

Safety information, not a substitute for the vehicle placard, the owner’s manual or a tire professional. Load and speed ratings apply to properly inflated, undamaged tires; check the numbers on your own tire and vehicle. Sources: UN Regulation No. 30 (Revision 3, including Supplement 15 to the 02 series; text as published in the Official Journal of the EU, L 201, July 30, 2008) and UN Regulation No. 54 (OJ L 183, July 11, 2008); U.S. Tire Manufacturers Association, Tire Care & Safety (2018); 49 CFR 571.110 (FMVSS 110), eCFR as of October 6, 2026; Continental, “Load index.” How we check our calculators.