Tire Comparison Calculator
Compare wheel and tire dimensions with scaled diagrams. See how a size change affects circumference, speedometer readings and clearance.
Quick-Load Popular Comparison Setups
Real-Time Visual GeometryDynamic Scaled Vector
Live synchronized engineering comparison scaled to exact millimeter ratios
Tire 1 (Stock / Current)
Wheel Width & Offset (ET)Optional
Tire 2 (Proposed / New Setup)
Wheel Width & Offset (ET)Optional
Performance & Engineering Analysis
| Tire Dimension / Metric | Tire 1 (Stock) | Tire 2 (New) | Delta Difference | % Variance |
|---|---|---|---|---|
| Overall Diameter | 634.3 mm (24.97") | 637.2 mm (25.09") | +2.9 mm (+0.12") | +0.46% |
| Section / Tread Width | 225.0 mm (8.86") | 225.0 mm (8.86") | 0.0 mm (0.00") | 0.0% |
| Sidewall Height | 101.3 mm (3.99") | 90.0 mm (3.54") | -11.3 mm (-0.45") | -11.15% |
| Circumference | 1992.7 mm (78.45") | 2001.8 mm (78.81") | +9.1 mm (+0.36") | +0.46% |
| Revolutions / Mile (Km) | 807.6 rev/mi (501.8/km) | 803.9 rev/mi (499.5/km) | -3.7 rev/mi | -0.46% |
| Vehicle Ride Height Delta | Reference Baseline | -- | +1.45 mm (+0.06") | Ground Lift |
How Tire Comparison Calculator Works
The tool uses the standard ISO metric tire-size formula. It works out the results in your browser as you change the inputs.
Enter your current tire
Pick the width, aspect ratio and rim diameter printed on your sidewall (for example 225/45 R17) as Tire 1, your factory baseline.
Choose the new size
Set the size you are considering as Tire 2, or load one of the popular upgrade presets such as a Plus 1 wheel swap or an all-terrain upsize.
Read the geometry
The calculator works out sidewall height, overall diameter, circumference and revolutions per mile, then draws both tires to the same scale.
Check speedometer & fitment
See how far your speedometer will be off, how ride height and clearance change, and whether the new size stays inside the ±3% tolerance.
Tire & Wheel Calculators & Comparators
Explore purpose-built calculators for speedo recalibration, wheel offset, rim clearances, gear ratios, tire load indexes, and wear forecasting.
Tire Size Comparison Calculator
Compare two tire sizes.
Multiple Tire Size Comparator
Compare several sizes together.
Tire Diameter Calculator
Estimate nominal overall diameter.
Tire Diameter Difference Calculator
Calculate absolute and percentage differences.
Tire Circumference Calculator
Estimate nominal circumference.
Tire Circumference Difference Calculator
Compare estimated rolling distances.
Tire Section Width Comparator
Compare nominal section widths.
Tire Sidewall Height Calculator
Calculate sidewall height from size markings.
Sidewall Height Difference Calculator
Compare sidewall height changes.
Tire Aspect Ratio Calculator
Derive aspect ratio from dimensions.
Tire Radius Calculator
Calculate nominal unloaded radius.
Rim Diameter Comparator
Compare required wheel diameters.
Tire Revolutions per Mile Calculator
Estimate rotations over one mile.
Tire Revolutions per Kilometer Calculator
Estimate rotations over one kilometer.
Published Revolutions Comparator
Compare manufacturer-listed rolling specifications.
Measured Tire Rollout Calculator
Calculate circumference from measured travel.
Nominal vs Published Dimensions Comparator
Compare estimates with manufacturer specifications.
Metric Tire Size Decoder
Explain width, aspect ratio, and rim diameter.
Flotation Tire Size Decoder
Explain inch-based truck tire dimensions.
Metric-to-Flotation Tire Converter
Express nominal dimensions in inches.
Flotation-to-Metric Tire Converter
Find approximate metric size equivalents.
Tire Dimension Unit Converter
Convert millimeters, inches, and centimeters.
Tire Size Input Validator
Check size notation and required fields.
Equivalent Diameter Tire Finder
Find sizes near a target diameter.
Target Diameter Tire Calculator
Solve for nominal aspect ratio.
Diameter Tolerance Filter
Filter candidates using specified limits.
Same-Rim Alternative Size Finder
Compare alternatives on one rim diameter.
Plus-One Tire Calculator
Compare sizes using larger wheels.
Plus-Two Tire Calculator
Compare sizes using two-inch wheel increases.
Custom Plus-Sizing Calculator
Explore specified wheel diameter increases.
Minus-Sizing Calculator
Compare sizes using smaller wheels.
Winter Wheel Size Comparator
Compare proposed winter wheel packages.
Stock vs Replacement Tire Comparator
Compare replacement dimensions with original specifications.
Passenger vs LT Tire Comparator
Compare dimensions and rated specifications.
Truck Tire Size Comparator
Compare metric and flotation truck sizes.
Spare Tire Size Comparator
Compare spare and road tire dimensions.
Staggered Tire Size Calculator
Compare front and rear sizes.
Front-to-Rear Circumference Calculator
Calculate axle-to-axle circumference differences.
AWD Tire Matching Comparator
Compare measurements against vehicle-specific limits.
Dual Tire Specification Comparator
Compare published spacing and load requirements.
Speedometer Error Calculator
Estimate speed changes after tire resizing.
Actual Speed Calculator
Estimate road speed from indicated speed.
Indicated Speed Calculator
Estimate displayed speed at a given road speed.
Speedometer Correction Factor Calculator
Calculate a tire-size correction multiplier.
Speedometer Correction Table Generator
Tabulate indicated and estimated actual speeds.
Odometer Error Calculator
Estimate distance recording differences.
Corrected Trip Distance Calculator
Adjust indicated distance for tire changes.
Corrected Fuel Economy Calculator
Adjust distance-based fuel economy readings.
Effective Gear Ratio Calculator
Calculate gearing changes from tire diameter.
Equivalent Axle Ratio Calculator
Find ratios preserving original effective gearing.
Engine RPM at Speed Calculator
Combine tire size and drivetrain ratios.
Vehicle Speed at RPM Calculator
Estimate speed from RPM and gearing.
Shift Speed Comparator
Compare theoretical speeds across gears.
Wheel Torque Change Calculator
Model gearing and tire-radius effects.
Theoretical Tractive Force Calculator
Combine wheel torque and tire radius.
Nominal Ground Clearance Change Calculator
Estimate clearance changes from tire radius.
Loaded Radius Comparator
Compare manufacturer-specified loaded tire radii.
Wheel Arch Gap Change Calculator
Estimate static vertical gap changes.
Inner Tire Clearance Change Calculator
Estimate changes toward suspension components.
Outer Tire Position Calculator
Estimate tire movement toward the fender.
Combined Wheel and Tire Comparator
Compare dimensions, widths, and offsets.
Wheel Offset Calculator
Calculate wheel mounting offset.
Wheel Offset Difference Calculator
Compare old and new offsets.
Wheel Backspacing Calculator
Calculate backspacing using specified wheel dimensions.
Backspacing-to-Offset Converter
Convert mounting measurements.
Wheel Frontspacing Calculator
Calculate outward wheel projection.
Wheel Width Comparator
Compare rim width changes.
Inner Wheel Clearance Calculator
Estimate changes at the inner wheel edge.
Outer Wheel Position Calculator
Estimate changes at the outer wheel edge.
Effective Offset with Spacer Calculator
Account for spacer thickness.
Spacer Position Change Calculator
Calculate inward and outward clearance changes.
Target Wheel Position Calculator
Solve for a desired static position.
Track Width Change Calculator
Estimate axle track changes.
Approved Rim Width Checker
Compare wheels with published tire limits.
Measuring Rim Width Comparator
Compare manufacturer measurement conditions.
Rim-Dependent Section Width Estimator
Estimate width changes within approved ranges.
Wheel Bolt Pattern Comparator
Compare bolt count and pitch diameter.
Wheel Center Bore Comparator
Compare hub and center bore dimensions.
Brake Clearance Template Comparator
Compare wheel-specific clearance templates.
Tire Load Index Decoder
Translate load index into rated capacity.
Tire Load Index Comparator
Compare replacement and original ratings.
Tire Speed Rating Decoder
Explain speed rating designations.
Tire Speed Rating Comparator
Compare specified speed categories.
Tire Service Description Comparator
Compare load index and speed rating.
Tire Load Range Comparator
Compare load range specifications.
Standard Load vs XL Comparator
Compare published load and pressure specifications.
Single vs Dual Load Comparator
Compare application-specific load ratings.
Load-at-Pressure Table Tool
Look up applicable load capacities.
Replacement Load Equivalence Tool
Compare capacity at specified pressures.
Axle Load Distribution Calculator
Allocate entered loads across tires.
Tire Capacity Margin Calculator
Compare entered loads with applicable capacities.
Tire Pressure Specification Comparator
Compare placard and manufacturer guidance.
Tire Pressure Unit Converter
Convert PSI, bar, and kPa.
Temperature–Pressure Scenario Calculator
Model pressure changes under stated assumptions.
Tire Tread Depth Converter
Convert millimeters and thirty-seconds of an inch.
Tread Depth Difference Calculator
Compare measured remaining tread.
Tread Wear Diameter Calculator
Estimate diameter reduction from tread loss.
New vs Worn Circumference Calculator
Compare approximate circumference changes.
Usable Tread Percentage Calculator
Compare tread with a selected replacement threshold.
Tire Wear Rate Calculator
Calculate measured wear per distance.
Tire Replacement Projection Calculator
Extrapolate recorded tread wear.
Four-Tire Wear Comparator
Compare tread readings across wheel positions.
Tire Age Calculator
Calculate age from a DOT date code.
Tire Age Comparator
Compare manufacture dates across a set.
UTQG Treadwear Comparator
Compare reported treadwear grades.
UTQG Traction Grade Comparator
Compare standardized traction grades.
UTQG Temperature Grade Comparator
Compare standardized temperature grades.
Tire Label Rating Comparator
Compare ratings within the same labeling scheme.
Rolling Resistance Comparator
Compare results from compatible test methods.
Wet Braking Test Comparator
Compare published results under matched conditions.
Tire Noise Comparator
Compare noise measurements under matched protocols.
Snow Performance Comparator
Compare published winter test results.
Tire Certification Marking Comparator
Compare reported certification markings.
Tire Weight Comparator
Compare published tire weights.
Wheel and Tire Package Weight Calculator
Compare complete assembly weights.
Tire Specification Comparator
Compare exact models in a common size.
Tire Model Size Variant Comparator
Compare specifications across one model’s sizes.
Tire Price per Unit Calculator
Compare individual tire prices.
Complete Tire Set Cost Calculator
Calculate costs for a specified quantity.
Installed Tire Cost Calculator
Include mounting, balancing, and entered fees.
Tire Rebate Comparison Calculator
Compare costs after applicable rebates.
Tire Cost per Mile Calculator
Use purchase cost and entered service life.
Tire Cost per Kilometer Calculator
Compare distance-based ownership costs.
Tire Warranty Comparator
Compare mileage coverage and conditions.
Prorated Tire Warranty Calculator
Apply a specified warranty schedule.
Wheel and Tire Package Cost Calculator
Compare complete replacement packages.
Tire Fuel Cost Scenario Calculator
Use entered fuel consumption assumptions.
Tire Package Break-Even Calculator
Compare extra costs with assumed savings.
Side-by-Side Tire Visualizer
Display nominal tire silhouettes.
Tire Overlay Visualizer
Overlay sizes to highlight dimensional differences.
Wheel Offset Visualizer
Illustrate wheel position changes.
Tire Comparison Chart Generator
Create dimension and specification tables.
Batch Tire Size Calculator
Process multiple candidate sizes.
Tire Comparison Report Generator
Export inputs, sources, and calculated differences.
Tire Sizing & Fitment Knowledge Base
Essential principles for tire upsizing, speedometer calibration, and suspension clearance
How to Read Tire Codes (e.g. 225/45 R17)
225: Nominal tire tread width in millimeters from sidewall to sidewall.
45: Aspect ratio profile. The sidewall height equals 45% of 225 mm (101.25 mm).
R: Radial construction method used in virtually all modern passenger vehicles.
17: Wheel rim diameter in inches that the bead seats onto.
The Golden 3% Tolerance Rule
Automotive engineers and tire manufacturers strongly recommend staying within ±3.0% (ideally within ±1.5%) of the OEM baseline tire diameter. Exceeding this boundary alters gear ratios, increases transmission heat load, introduces substantial speedometer inaccuracies, and can disrupt electronic stability control (ESC) and anti-lock braking (ABS) pulse algorithms.
What is "Plus Sizing" (+1, +2)?
Plus sizing is upgrading to a larger rim diameter (e.g., from 17" to 18" or 19") while proportionately reducing the tire sidewall aspect ratio (e.g., from 45 to 40 or 35). This maintains identical rolling diameter and speedometer accuracy while giving sharper steering response and filled-out wheel-well aesthetics.
Wheel Offset (ET) & Clearance Impact
Offset (measured in mm ET) specifies the distance from the wheel's mounting hub to its true centerline. Lower positive or negative offsets push wheels outward toward the fender lips (stance look), while higher offsets draw the wheel closer inward to brake calipers and suspension struts.
Frequently Asked Tire Fitment Questions
Can I put wider tires on my factory rims?
Generally, you can step up 10mm to 20mm in width (for example from 215mm to 225mm) without changing the wheel, provided your rim width is within the tire manufacturer's approved rim width range. Mounting too wide a tire on a narrow rim causes excessive tire bulge, sidewall flex, and uneven tread wear.
Why is my speedometer reading fast or slow after changing tire sizes?
Your vehicle's computer calculates velocity based on wheel revolutions per minute. If you install taller tires, each wheel revolution travels farther along the road than stock, meaning your vehicle moves faster than the speedometer displays. Taller tires cause your speedometer to read slow; shorter tires cause your speedometer to read fast.
Does changing tire diameter affect vehicle warranty or AWD systems?
On All-Wheel-Drive (AWD) vehicles like Subaru Symmetrical AWD, Audi quattro, or BMW xDrive, all 4 tires MUST share identical diameters (often within 2/32" or 1% circumference). Mismatched rolling circumferences between axles cause continuous slip in the center differential, resulting in mechanical overheating and potential failure.
How is overall tire diameter calculated?
Overall diameter equals the rim diameter plus two sidewall heights. The sidewall height is the section width multiplied by the aspect ratio. For a 225/45 R17 tire: 225 × 0.45 = 101.25 mm per sidewall, and 17 in × 25.4 = 431.8 mm for the rim, giving 431.8 + (2 × 101.25) = 634.3 mm, or about 24.97 inches.
How much bigger can I go with a new tire size?
Most tire and vehicle manufacturers recommend keeping the new overall diameter within ±3% of the original size, and ideally within ±1.5%. Beyond that, speedometer error, ABS and stability-control behavior, and fender or suspension clearance can all be affected. Always confirm physical clearance with a qualified tire installer.
Are the calculated dimensions exactly what my tires will measure?
No. The calculator uses the nominal ISO metric sizing formula. Real tires vary by brand, tread design, rim width and inflation pressure, so measured diameter and width can differ by several millimeters. Use the results to compare sizes and shortlist options, then check the manufacturer's published specifications.