What is load index 18?

Load index 18 means one tire is rated to carry 75 kg, which is 165 lb, at the inflation pressure the standard specifies for its load range.

How much can four tires with load index 18 carry?

300 kg (661 lb) between them, if every tire is correctly inflated. That figure does not raise the vehicle's own gross weight rating, which is usually the lower limit and the one that governs.

Is load index 18 enough for my vehicle?

This site cannot answer that. The vehicle placard in the driver's door jamb states the load index the vehicle was built around, and a replacement has to meet or exceed it. That placard is the authority, not a table.

Load index 18

One tire rated at load index 18 carries 75 kg, which is 165 lb. Four of them carry 300 kg (661 lb) between them.

A load index is the capacity of one tire at the inflation pressure the standard specifies for that rating, on a correctly sized rim, on a sound and undamaged tire. It is not a capacity at any pressure you choose, and it is not a licence to load a vehicle past its own axle and gross weight ratings.

Per tire: 75 kg
Per tire: 165 lb
Sources: 2

What load index 18 works out to

Load index 18 in several forms
Situation	Kilograms	Pounds
One tire	75	165
One axle (two tires)	150	331
Set of four	300	661
One tire, P-metric or Euro-metric fitted to a light truck (divided by 1.1)	68.2	150

A P-metric or Euro-metric tire fitted to a light truck, van, SUV or trailer carries less than its load index states. Divide the rated load by 1.1. An LT tire of the same nominal size is not derated, which is why an LT size and a P size that look alike are not interchangeable at rated load.

A tire rated for dual (twinned) fitment prints two load indices, for example 121/118S. The first applies when one tire is mounted per hub, the second when two are. Look the second index up in this table rather than working out a percentage - the printed pair is the rating, and any percentage is a description of it.

Indices either side

Load indices near 18
Index	Kilograms	Pounds	Difference from 18
15	69	152	-6 kg
16	71	157	-4 kg
17	73	161	-2 kg
19	77.5	171	+2.5 kg
20	80	176	+5 kg
21	82.5	182	+7.5 kg

Questions about load index 18

What is load index 18?: Load index 18 means one tire is rated to carry 75 kg, which is 165 lb, at the inflation pressure the standard specifies for its load range.
How much can four tires with load index 18 carry?: 300 kg (661 lb) between them, if every tire is correctly inflated. That figure does not raise the vehicle's own gross weight rating, which is usually the lower limit and the one that governs.
Is load index 18 enough for my vehicle?: This site cannot answer that. The vehicle placard in the driver's door jamb states the load index the vehicle was built around, and a replacement has to meet or exceed it. That placard is the authority, not a table.

Where these figures come from

Computed on this page, not looked up. Each figure and the arithmetic behind it:

Pounds pounds = kilograms x 2.20462262185, rounded to the nearest pound
Light truck derating rated load / 1.1, for a P-metric or Euro-metric tire on a light truck

Published values here were read from 2 independent sources:

Tyre Load Index Chart (LI 0-150) - AmesWeb, states ETRTO and SAE tables as the basis (read 2026-08-27)
Load index 0 to 150, kilograms
Tire Load Rating Chart - Your Auto Vision, page dated 21 April 2026 (read 2026-08-27)
Load index 0 to 150, kilograms and pounds; load range letters

These are independent publishers, not independent measurements. Each one reproduces a table originally set by a standards body, so agreement between them shows a value was transcribed correctly, not that the underlying table is right. Where a figure is safety relevant, check it against the tire manufacturer's own data before relying on it.