Tire load index chart explained — what 95, 100, 121 actually carry

The two or three digit number before the speed rating on a tire size code is the load index — the maximum weight that tire is rated to carry at the listed inflation pressure. Here is the full chart, what to do for towing, and why under-rating costs more than people realize.

On a sidewall code like 235/40R18 95Y, the 95 is the load index. It is one number in a single global table that maps to a specific maximum weight at the tire's rated inflation pressure. The fact that the index goes in increments and not in literal pounds is what makes it confusing — a load index of 95 is 1,521 lb, 100 is 1,764 lb, 110 is 2,337 lb, and 121 is 3,297 lb. The jumps are non-linear, and reading the wrong row of the chart is a common pre-purchase error.

What the index means

The load index is the maximum load (per tire) that the manufacturer certifies at the tire's rated maximum cold inflation pressure. The full table runs from 0 (99 lb) to 279 (over 300,000 lb for industrial applications). Consumer passenger tires almost always sit in the 79 (882 lb) to 116 (2,756 lb) range. Light-truck and trailer tires often range up to the 120s.

The number is per tire, not per vehicle. A vehicle's total tire load capacity is the sum across all four — but tires don't carry equally, and at any given moment one corner of the car (loaded heavy in the trunk, cornering hard, hitting a pothole) can carry well above the average. The rated capacity exists to provide margin for that.

Common rows you'll see on the sidewall

• 82 — 1,047 lb. Common on small economy cars.
• 89 — 1,279 lb. Compact sedans, small crossovers.
• 91 — 1,356 lb. Mid-size sedans.
• 94 — 1,477 lb. Larger sedans, base trim crossovers.
• 95 — 1,521 lb. Most touring all-season passenger tires.
• 100 — 1,764 lb. Mid-size SUVs, larger crossovers.
• 104 — 1,984 lb. Large SUVs.
• 110 — 2,337 lb. Half-ton trucks, large SUVs.
• 116 — 2,756 lb. Heavy half-ton, light three-quarter-ton trucks (E-rated LT tires).
• 121 — 3,297 lb. Three-quarter and one-ton trucks at full payload.
• 126 — 3,748 lb. One-ton heavy-duty trucks, fifth-wheel trailers.

The number is non-linear because the actual table uses a logarithmic relationship between index value and rated load. Each step is roughly a 2.5% load increase, not a fixed pound increase.

Why placard matching matters

The door-jamb placard on every US-market vehicle specifies the OEM load index along with the size, speed rating, and pressure. The manufacturer determined the placard load index by adding the vehicle's curb weight to its maximum payload (the "GVWR minus curb weight" published on the placard), dividing by 4, and applying a safety margin. Falling below the placard load index in your replacement tires under-equips the vehicle for its design payload — a fully loaded family minivan with a downgraded load index has less reserve when one tire takes the bulk of the load over a pothole.

Going over the placard load index is always fine. A 100-rated replacement on a 95-placard vehicle is over-equipped, which is harmless apart from a small ride-stiffness penalty.

Towing math

If you tow, the load math gets harder. The placard rates the tires for the vehicle at its maximum GVWR. If you add a trailer with tongue weight, that tongue weight transfers onto the rear axle of the tow vehicle — meaning the rear tires now carry the rear-axle share of the curb-plus-payload weight plus the tongue weight, while the fronts carry slightly less than placard.

For a half-ton truck with a 110-load-index OEM tire (2,337 lb per tire, 4,674 lb rear axle capacity), towing a 7,000 lb trailer with 700 lb tongue weight adds 350 lb to each rear tire on top of the existing payload. Most owners stay within margin, but loading a truck bed near GVWR and towing near maximum tongue weight can put a single rear tire above its rated capacity. The fix is usually to step up to an LT-rated tire with a higher load index (typically 121 or 126) when running near maximum payload. See our towing tire guide.

What goes wrong when you under-rate

Under-rated tires don't fail immediately. They run hotter than they should under any given load. Higher operating temperature accelerates the same compound degradation that makes tires age out — so an under-rated tire is also a faster-aging tire. The visible failure mode, when it comes, is usually a tread separation rather than a sudden burst; the heat soak weakens the belt-to-rubber bond over thousands of miles before the tire actually fails. NHTSA's tire complaint data over the past 15 years shows a meaningful concentration of belt-separation complaints on vehicles where the replacement tire's load index was lower than the placard — usually a result of well-meaning installers substituting a cheaper tire when the OEM-spec size was out of stock.

Where to find it

On any sidewall code, the load index is the two- or three-digit number immediately before the speed rating letter. On the door-jamb placard it appears in the same format. The two should match (or your replacement should exceed the placard) every time you buy tires.

By Mark Bishop · Updated 2026-05-21.