Tire Load Index & Speed Rating Lookup

The Tire Load Index & Speed Rating Lookup decodes the service description printed on your tire — the number and letter at the end of a code like 225/45R17 94V. The number (94) is the load index, telling you the maximum weight each tire can carry, and the letter (V) is the speed rating, telling you the maximum speed the tire is certified for. Paste your full tire size or just the service description and this tool converts both codes into real-world limits in kg, lbs, km/h, and mph.

What Is the Tire Service Description?

Every passenger tire carries a size code such as 225/45R17 94V. The first part, 225/45R17, describes the tire's dimensions and construction. The final two symbols, 94V, are the service description: the load index and the speed rating. Together they define how much weight the tire can safely support and how fast it can safely go.

What Is a Tire Load Index?

The load index is a numeric code — not the weight itself. Each number maps to a maximum load in kilograms via a standardized chart. For example, a load index of 94 means each tire can carry up to 670 kg (1,477 lbs) at its rated inflation pressure. Multiply by the number of tires to find the total weight a full set can support. Fitting a tire with a lower load index than your vehicle requires can overload the tire and is unsafe.

What Is a Tire Speed Rating?

The speed rating is a letter that indicates the maximum speed the tire can sustain while carrying its rated load. A V rating, for instance, certifies the tire to 240 km/h (149 mph). Higher ratings indicate better high-speed heat resistance and handling. You can safely fit a tire with an equal or higher speed rating than your vehicle's original specification, but a lower rating is not recommended.

Load Index Chart

Maximum load per tire for each load index in the common passenger and light-truck range.

Use the lookup above for any index from 50 to 150 — this chart shows the most common values.

Speed Rating Chart

Note the order: H (210 km/h) sits between U (200) and V (240) — a historical quirk of the rating system.

Why the Load Index and Speed Rating Matter

How to Use This Calculator

1. Find the code on your sidewall: Look for a size such as 225/45R17 94V. The 94V at the end is the service description.
2. Enter the code: Type the full tire size or just the service description like 94V into the lookup field.
3. Choose how many tires: Select 1, 2, 4, or 6 tires to see the total supported load.
4. Read the results: See the maximum load per tire in kg and lbs, the total across your set, and the maximum speed rating in km/h and mph on the visual gauge.

Frequently Asked Questions

What is a tire load index?

The load index is the number in the service description of a tire code, such as the 94 in 225/45R17 94V. It is a coded value that corresponds to the maximum load one tire can carry at its rated pressure. A load index of 94, for example, means each tire can support up to 670 kg (1,477 lbs).

What is a tire speed rating?

The speed rating is the letter in the service description, such as the V in 225/45R17 94V. It indicates the maximum speed the tire is certified to sustain when carrying its rated load. A V rating means the tire is approved for speeds up to 240 km/h (149 mph).

Where do I find the load index and speed rating?

They appear together at the end of the tire size code on the sidewall. In 225/45R17 94V, the size is 225/45R17 and the service description is 94V, where 94 is the load index and V is the speed rating.

Can I use a tire with a higher load index or speed rating?

Yes. Fitting a tire with an equal or higher load index and an equal or higher speed rating than the vehicle manufacturer specifies is generally safe. Never fit a lower load index, as the tire may be overloaded, and avoid a lower speed rating than recommended.

What does ZR mean on a tire?

ZR is a legacy marking indicating the tire is rated for speeds above 240 km/h. Modern ZR tires also carry a specific letter such as W or Y that gives the exact maximum speed, for example 225/45ZR17 94Y is rated to 300 km/h.

Is a higher speed rating always better?

A higher speed rating usually means better high-speed handling and heat resistance, but such tires can wear faster and may offer a firmer ride. The best choice matches or exceeds your vehicle's original specification for your normal driving conditions.

Additional Resources

• Tire Code - Wikipedia
• Tire Load and Speed Ratings - Wikipedia