Tire Load Index Calculator
Decode the load index and speed rating on your sidewall, and check whether a set of tires can legally carry your vehicle.
Sidewall markings
- Load capacity is per tire at the maximum inflation pressure marked on the sidewall.
- Never fit a tire with a lower load index than the manufacturer's placard specifies.
- Speed ratings assume a correctly inflated tire in good condition. A repaired tire loses its rating.
Reading the sidewall
A marking like 225/60R16 95H ends with two pieces of rating information. The 95 is the load index, which maps to 1,521 pounds per tire through a standard table. The H is the speed rating, good for 130 mph.
Four tires at index 95 carry 6,084 pounds between them, which needs to comfortably exceed the vehicle's gross weight rating with room for passengers and cargo.
Never go down
The load index on the door placard is a minimum. Going lower puts the tire structure closer to its limit every time the vehicle is loaded, and heat builds in an overloaded tire until the belts separate. Going higher is always safe from a load perspective, though heavy-duty tires ride firmer.
This catches people fitting passenger-rated tires to light trucks and vans. An SUV that came with an XL or Load Range E tire needs one, and a standard load tire in the same size is not a substitute.
Speed ratings are a structural limit
A speed rating is the sustained speed a tire can hold at full load without the structure failing from heat. It is not a recommendation, and it is not a performance measure. Dropping a speed rating below the placard also usually means a softer sidewall, which changes how the car steers.
Frequently asked questions
What does load index 95 mean?
1,521 pounds per tire. The index is a code into a standard table rather than a direct measurement, so 95 means 1,521 lb, 96 means 1,565 lb, and so on. Four tires at index 95 support 6,084 lb in total.
Can I use a higher load index than specified?
Yes, that is always safe from a load standpoint and is often what you want on a vehicle that tows or carries weight. The trade-off is a stiffer sidewall and a firmer ride, and heavier tires blunt acceleration and economy slightly.
What happens if I fit a lower speed rating?
The tire's structure is rated for less sustained heat. For most driving nothing happens, but it may invalidate insurance in some jurisdictions and the softer construction usually makes steering feel vaguer. Manufacturers pick the rating deliberately.
Does load capacity depend on tire pressure?
Yes, entirely. The rated capacity applies at the maximum inflation pressure on the sidewall. An underinflated tire carries substantially less, which is why overloading and underinflation together is the classic recipe for a blowout.
Everything on this page is an estimate worked out from the numbers you entered and typical figures for the conditions you picked. Your vehicle, your parts and your conditions will differ. Check anything you intend to act on against the manufacturer's specification, the service manual, or a qualified technician. Verifying the result before relying on it is up to you.