Load, Pressure & Safety

Tire Load Index Decoder

Translate any tire load index into maximum load capacity in kg and lb. Includes the load for a full set of 4 tires.

Load, Pressure & Safety

Translate load index into rated capacity.

Open Live Calculator

Tire Load Index Decoder: Tire Size Inputs

Compare two tire sizes here. Use the formulas and reference tables below for this tool's specific calculation.

ISO/TRA Compliant

Baseline Tire (T1)Stock OEM

Width (mm)

Aspect (%)

Rim (in)

Comparison Tire (T2)Proposed Setup

Width (mm)

Aspect (%)

Rim (in)

Baseline OD634.3 mm24.97"

Comparison OD637.2 mm25.09"

Diameter Variance+2.9 mm+0.46%

Speed @ 60 MPH60.3 MPH-4 revs/mi

How Tire Load Index Decoder Works?

The Tire Load Index Decoder works by looking up the load index number in the standard ISO and ETRTO load table and returning the matching capacity. The tool uses 3 steps.

Find the index
Read the number after the size, for example 94 in 225/45 R17 94W.
Look up the capacity
The decoder returns 670 kg (1,477 lb) for index 94.
Scale to a set
The decoder multiplies by 4 to show 2,680 kg (5,908 lb) for a full set at the reference pressure.

Tire Load Index Decoder Formula

The Tire Load Index Decoder uses a lookup table, not a formula. Each index step raises capacity by about 3%, so L(i) ≈ 45 × 1.030^i kg approximates the table.

Exact valueL(i) = Table[i] (ISO 4000-1 / ETRTO)

ApproximationL(i) ≈ 45 × 1.030^i kg

PoundsL_lb = L_kg × 2.20462

Set capacityL_set = 4 × L(i)

i: Load index number
L(i): Maximum load per tire at reference pressure (kg)

Worked example

Load index 98 equals 750 kg (1,653 lb) per tire. Load index 121 equals 1,450 kg (3,197 lb) per tire.

Tire Load Index Decoder Conversion Table

The Tire Load Index Decoder conversion table lists 17 load index values from 75 to 123 with capacity per tire and per set.

Load index 75 to 123 in steps of 3
Load index	Capacity (kg)	Capacity (lb)	Set of 4
75	387 kg	853 lb	1,548 kg (3,413 lb)
78	425 kg	937 lb	1,700 kg (3,748 lb)
81	462 kg	1,019 lb	1,848 kg (4,074 lb)
84	500 kg	1,102 lb	2,000 kg (4,409 lb)
87	545 kg	1,202 lb	2,180 kg (4,806 lb)
90	600 kg	1,323 lb	2,400 kg (5,291 lb)
93	650 kg	1,433 lb	2,600 kg (5,732 lb)
96	710 kg	1,565 lb	2,840 kg (6,261 lb)
99	775 kg	1,709 lb	3,100 kg (6,834 lb)
102	850 kg	1,874 lb	3,400 kg (7,496 lb)
105	925 kg	2,039 lb	3,700 kg (8,157 lb)
108	1000 kg	2,205 lb	4,000 kg (8,818 lb)
111	1090 kg	2,403 lb	4,360 kg (9,612 lb)
114	1180 kg	2,601 lb	4,720 kg (10,406 lb)
117	1285 kg	2,833 lb	5,140 kg (11,332 lb)
120	1400 kg	3,086 lb	5,600 kg (12,346 lb)
123	1550 kg	3,417 lb	6,200 kg (13,669 lb)

What is Tire Load Index Decoder?

A Tire Load Index Decoder is a tool that converts the load index number on a tire into the maximum weight one tire carries. The load index sits in the service description next to the speed rating, for example 94 in 94W.

The load index is a code, not a weight. Index 100 equals 800 kg (1,764 lb), not 100 kg.

The capacity applies at the reference pressure for the tire's construction. A tire run below that pressure carries less.