Complete Tire Size Chart &
Conversion Guide 2024

The ultimate reference for tire sizing: conversion tables, diameter calculations, width comparisons, and fitment guides for every vehicle type. Used by 280,000+ monthly users worldwide.

500+
Tire Sizes
P-Metric
Standard
LT
Light Truck
Metric
European
Understanding SizesConversion ChartWidth GuideDiameter ChartAspect RatiosUse Calculator

How to Read Tire Size Numbers

P 235 / 45 R 18 94 W
P
Type
235
Width
45
Aspect
R
Radial
18
Rim
94W
Load/Speed

🔤 P = Tire Type

P = Passenger car
LT = Light Truck
ST = Special Trailer
T = Temporary spare
No letter = European metric

📏 235 = Width (mm)

Tire width measured in millimeters from sidewall to sidewall. Common widths range from 145mm (narrow) to 335mm (extra wide). Wider = better grip, narrower = better fuel economy.

📐 45 = Aspect Ratio

Sidewall height as % of width. 45 means sidewall is 45% of 235mm = 105.75mm tall. Lower number = shorter sidewall = sportier handling. Higher = more comfortable ride.

⭕ R = Construction

R = Radial (99% of modern tires)
D = Diagonal/Bias (vintage)
B = Belted bias (rare)
Radial provides better handling and longevity.

🔵 18 = Rim Diameter

Wheel/rim diameter in inches (not mm!). Common sizes: 15"-22" for cars, 17"-24" for trucks. Must match your wheel size exactly. Cannot install 18" tire on 17" wheel.

⚖️ 94W = Load/Speed

94 = Load index (1,477 lbs capacity)
W = Speed rating (168 mph max)
Critical for safety - never downgrade load rating or speed rating below OEM specs.

⚠️ Important Safety Note:

Always consult your vehicle's door jamb sticker or owner's manual for the correct tire size. Installing incorrect tire sizes can affect speedometer accuracy, vehicle handling, clearance, and safety. When in doubt, consult a professional tire technician.

Complete Tire Size Conversion Chart

This comprehensive chart shows equivalent tire sizes across different standards. Use it to find alternative sizes with similar overall diameter (±3% recommended maximum).

🚗Passenger Car Tire Sizes (P-Metric)

Tire SizeOverall DiameterSection WidthCircumferenceCommon Vehicles
P195/65R1525.0"7.7"78.5"Honda Civic, Toyota Corolla
P205/55R1624.9"8.1"78.1"Honda Accord, Mazda 3
P215/60R1626.2"8.5"82.1"Nissan Altima, VW Jetta
P225/65R1728.5"8.9"89.5"Honda CR-V, Toyota RAV4
P235/45R1826.3"9.3"82.6"Tesla Model 3, BMW 3-Series
P245/40R1926.7"9.6"83.8"Audi A4, Mercedes C-Class
P255/35R2027.0"10.0"84.9"Mustang GT, Camaro SS

🚙Light Truck Tire Sizes (LT-Metric)

Tire SizeOverall DiameterSection WidthLoad RangeCommon Vehicles
LT265/70R1731.6"10.4"E (10-ply)Ford F-150, Ram 1500
LT275/65R1832.1"10.8"E (10-ply)Chevy Silverado, GMC Sierra
LT285/70R1732.7"11.2"E (10-ply)Toyota Tundra, Nissan Titan
LT295/70R1834.3"11.6"E (10-ply)Ford F-250, Ram 2500
LT315/70R1734.4"12.4"E (10-ply)Jeep Gladiator, Ram Power Wagon
LT35x12.50R1735.0"12.5"E (10-ply)Jeep Wrangler (lifted), F-150 Raptor
LT Tire Note:Load Range E (10-ply) is the most common for 1/2 ton and 3/4 ton trucks. Requires 60-80 PSI inflation vs 35-42 PSI for P-metric tires. Always check door jamb sticker for correct pressure.

⛰️Flotation Tire Sizes (Off-Road)

Flotation SizeMetric EquivalentOverall DiameterSection WidthCommon Use
31x10.50R15LT265/75R1531.0"10.5"Jeep TJ, Toyota Tacoma
33x12.50R15LT285/75R1633.0"12.5"Jeep Wrangler (2.5" lift)
35x12.50R17LT315/70R1735.0"12.5"Jeep Wrangler (3.5" lift)
37x12.50R17LT325/65R1837.0"12.5"Rock crawler (4"+ lift)

Need to Compare Specific Tire Sizes?

Use our advanced tire size calculator to compare any two tire sizes, see exact diameter differences, speedometer error, and clearance requirements.

Launch Tire Calculator →Compare Two Sizes

Tire Width Conversion Guide (mm to inches)

Convert between metric millimeter width and approximate inch equivalents. Note that section width varies slightly based on rim width - these are nominal values.

145mm
5.7"
Narrow Width
Compact cars, economy
155mm
6.1"
Narrow Width
Small sedans, city cars
165mm
6.5"
Narrow Width
Subcompact, hybrids
175mm
6.9"
Standard Width
Compact sedans
185mm
7.3"
Standard Width
Economy sedans
195mm
7.7"
Standard Width
Mid-size sedans
205mm
8.1"
Standard Width
Family sedans, compact SUVs
215mm
8.5"
Standard Width
Mid-size cars, crossovers
225mm
8.9"
Wide Width
SUVs, performance cars
235mm
9.3"
Wide Width
Sports sedans, crossovers
245mm
9.6"
Wide Width
Performance cars, large SUVs
255mm
10.0"
Wide Width
Sports cars, trucks
265mm
10.4"
Extra Wide Width
Trucks, performance SUVs
275mm
10.8"
Extra Wide Width
Trucks, muscle cars
285mm
11.2"
Extra Wide Width
HD trucks, off-road
295mm
11.6"
Extra Wide Width
Heavy-duty trucks
305mm
12.0"
Ultra Wide Width
Supercars, HD trucks
315mm
12.4"
Ultra Wide Width
Off-road, rock crawlers

Aspect Ratio Guide: What Do the Numbers Mean?

The aspect ratio (second number in tire size) represents sidewall height as a percentage of width. Lower = sportier handling, higher = more comfortable ride and better off-road capability.

25-35

Ultra Low Profile
  • ✓ Maximum handling
  • ✓ Sharp steering response
  • ✗ Harsh ride quality
  • ✗ Wheel damage risk
  • ✗ Expensive tires
Examples: Sports cars, supercars
275/35R20, 245/30R21

40-50

Low Profile
  • ✓ Sporty handling
  • ✓ Good looks
  • ✓ Balanced performance
  • ✗ Firmer ride
  • ✗ Higher cost
Examples: Sport sedans, performance crossovers
235/45R18, 255/40R19

55-65

Standard Profile
  • ✓ Comfortable ride
  • ✓ Good fuel economy
  • ✓ Affordable
  • ✓ All-season versatile
  • ✗ Less sporty feel
Examples: Family sedans, crossovers, SUVs
215/60R16, 225/65R17

70-85

High Profile
  • ✓ Maximum comfort
  • ✓ Off-road capability
  • ✓ Pothole protection
  • ✓ Towing stability
  • ✗ Softer handling
Examples: Trucks, off-road vehicles
LT265/70R17, LT285/75R16

Tire Size Chart FAQs

Can I use a tire size chart to find alternative tire sizes?
Yes, but with caution. Alternative sizes should be within ±3% of your original tire's overall diameter to avoid speedometer error, clearance issues, and drivetrain problems. Our tire size calculator shows exact percentage differences. Always verify clearance by test-fitting or consulting a professional.
What's the difference between P-metric and LT-metric tire sizes?
P-metric (Passenger) tires are designed for cars, minivans, and light-duty SUVs with max load around 1,200-2,000 lbs per tire at 35-42 PSI. LT-metric (Light Truck) tires are built for pickups, heavy SUVs, and commercial vehicles with reinforced construction supporting 2,000-4,000+ lbs per tire at 50-80 PSI. LT tires have Load Range ratings (C/D/E) instead of load index numbers.
How do I convert flotation tire sizes (like 33x12.50R15) to metric?
Flotation sizes list diameter first (33 inches), then section width (12.50 inches), then construction (R=radial), then rim diameter (15 inches). To convert to metric: 33x12.50R15 ≈ LT285/75R16. The metric equivalent isn't exact - use our calculator for precise comparisons. Flotation sizing is common for off-road and mud-terrain tires.
Why do tire sizes use millimeters for width but inches for rim diameter?
Historical reasons. Tire width adopted European metric standards (millimeters) in the 1960s for precision, but rim sizes stayed in imperial inches because wheel manufacturing was established in the US/UK. This hybrid system persists globally today. Some European sizes use all-metric (e.g., 195/65R390 where 390mm = rim diameter), but these are rare.
What's a safe range for changing tire size?
Industry standard: ±3% diameter change maximum. This equals ±2 mph speedometer error at 60 mph. Exceeding 3% can cause: speedometer/odometer inaccuracy, ABS/traction control issues, rubbing/clearance problems, gear ratio changes affecting performance and fuel economy. Some vehicles tolerate up to 5% with modifications, but consult a professional first.
Can I mix different tire sizes on the same vehicle?
Generally NO for safety and legal reasons, with exceptions: 1) Staggered setups (different front/rear) are factory-spec on some performance cars (BMW M3, Corvette). 2) Temporary spare (T-rated) for emergency use only, max 50 mph. 3) AWD/4WD vehicles require all four tires within 2/32" tread depth difference to avoid drivetrain damage. Never mix sizes on same axle.
How often do tire size standards change?
TRA and ETRTO update standards annually but changes are incremental. New sizes are added for new vehicles (e.g., electric vehicles needing high-load, low-resistance tires), but existing size specifications rarely change. Our database updates quarterly to include new OEM tire sizes. Classic vehicle sizes from 1960s+ remain unchanged and still manufactured.
Do all tire brands size the same for a given tire size?
No - there's ±3% manufacturing tolerance. A 265mm tire can measure 258-272mm actual width depending on brand, model, and rim width. Michelin Pilot Sport 4S and Hankook Ventus V12 in same size may differ by 5-10mm section width. This affects fitment on lowered vehicles or tight wheel wells. Always verify actual measurements when clearance is critical.