What is a tire load index?

Load index is a number on the tire that indicates the maximum weight that one tire can carry at the specified pressure. Higher numbers mean higher carrying capacity.

How do I use this calculator?

Enter your ready-to-roll vehicle weight (curb weight plus passengers and cargo). The tool divides by four and adds a safety margin to suggest the minimum load index per tire. If you know your axle split, enable the axle option for a more precise result.

Can I choose a lower load index than my original tires?

No. Never choose a tire with a load index lower than the vehicle manufacturer’s specification on the door placard. Downgrading can lead to unsafe overload conditions.

What safety margin should I use?

A 10–15% reserve covers typical variations in passengers, cargo, and weight distribution. If you frequently tow or carry heavy loads, consider a higher reserve and consult a fitment specialist.

Does front/rear weight distribution matter?

Yes. Vehicles are often nose- or tail-heavy. If you know your axle weights or percentages, use the axle distribution option. The calculator selects the higher per-tire load between the two axles.

Tire Load Index Calculator

Load Index / Weight Calculator

Enter ready-to-roll vehicle weight (curb + passengers + cargo). We’ll divide by four and add a safety margin to suggest the minimum tire load index. Never choose a lower load index than your OE placard.

Units

Ready-to-roll vehicle weight

Includes curb weight + passengers + cargo

Reserve capacity (safety margin): 10%

Adds extra capacity to each tire’s requirement

Use axle distribution (front/rear)

Result

Per-tire requirement

—

Includes selected safety margin

Total ready weight

—

User entered

Minimum load index (per tire)

—

Capacity per tire: —

Nearby load indexes

Load Index	Capacity (lb)	Capacity (kg)

Important: Always follow the vehicle manufacturer placard and never downgrade load index. Weight isn’t always 50/50 front/rear; if you know your axle weights, use the axle option.

Need help? Contact a fitment specialist · Shop tires by vehicle: Search by Vehicle

Key Takeaways

Never downgrade load index. Match or exceed the load index shown on your vehicle placard and original tires.
Calculate with real-world weight. Use curb weight plus passengers and cargo; add a sensible reserve for safety.
Front/rear isn’t always 50/50. If you know axle split, size to the higher per-tire load.
Inflation matters. Load capacity assumes correct pressure; check your placard and monitor TPMS.

Next Steps

Shop Tires by Vehicle Wheel & Tire Packages Financing Options Talk to a Fitment Specialist

Fitment Notes

LT / Commercial tires: Load index and inflation tables differ from P-metric; follow manufacturer data.
Towing & payload: Frequent heavy loads may require a higher reserve capacity and different tire class.
Mixed sets: Avoid mixing different load indexes or constructions on the same axle.

Reviewed by the Performance Plus Tire Fitment Team

This tool is for guidance only and assumes properly maintained tires inflated to the vehicle placard pressure. Always follow the vehicle manufacturer specifications and consult our team for edge cases (lifted vehicles, aftermarket load changes, towing, or commercial use).