Know Your Tires Before You Buy or Swap

Calculate exact internal air volume of any tire in liters, gallons & cubic inches — useful for sealant dosing and capacity comparison.

Find how much your speedometer reads off after a tire size change — get real speed at any indicated reading and odometer error %.

Calculate static, loaded, and dynamic rolling radius plus circumference and revs per mile for any P-metric tire.

Convert wheel ET offset to backspacing and estimate outer poke and inner clearance for custom fitment.

Check if staggered front/rear tires are safe for AWD and xDrive — compares diameter difference and rolling radius.

Calculate exact scrub radius from SAI, spindle offset, and wheel ET — or instantly see how a wheel swap or spacer shifts your scrub radius, with drivetrain safety rating.

Find minimum, ideal, and maximum rim width for any tire section width based on industry correlation tables.

Convert between P-Metric and Flotation tire sizes and compare two sizes with diameter, sidewall, and speedometer error.

Calculate tire contact patch area in sq in and cm² from vehicle load and inflation pressure.

Find recommended tire pressure by vehicle type and convert PSI ↔ kPa instantly.

Instantly convert tyre pressure between PSI and kPa — perfect for UK and European vehicles.

Decode your tire DOT code to find manufacture date and age — get a safety warning if tires are over 6 years old.

Compare spare tire diameter to primaries and check AWD/4WD tolerance to avoid drivetrain damage.

Compare two tire sizes side-by-side — diameter, sidewall, speedometer error, and revs/mile instantly.

Find the exact diameter difference between two tire sizes with safe-change %, speedometer error, and AWD tolerance.

Solve for the aspect ratio needed to hit a target diameter — ideal for plus-sizing while keeping speedometer error under ±3%.

Understand UTQG temperature grades (A, B, C) and what they mean for heat resistance and high-speed safety.

Estimate inner suspension clearance and outer fender poke when changing wheel width, offset, or tire size.

Check if your tire width is compatible with your rim — see stretch or pinch estimate and safety bands.

Find Plus-0, Plus-1, and Plus-2 tire sizes within safe diameter range with speedometer error and fitment impact.

Calculate remaining tread life from depth in 32nds or mm and decode UTQG treadwear ratings.

Convert tire speed rating letters (Q–ZR) to max safe speed in mph and km/h with OEM matching guidance.

Calculate exact sidewall height in mm and inches from tire width and aspect ratio.

Convert tire Load Range (SL, XL, C–H) to ply rating, max PSI, and typical use for LT and trailer tires.

Convert tire Load Index to max load capacity in lbs and kg — match it to your vehicle GVWR safely.

See how bigger tires affect effective gear ratio and RPM — calculate the regear needed to restore stock performance.

Understand positive, negative, and zero caster — how it affects steering feel, self-centering, and tire wear.

Calculate engine RPM at any speed from tire size, axle ratio, and gear — see the RPM impact of bigger tires.

Understand toe-in, toe-out, and zero toe — how small changes affect stability, turn-in, and tire wear.

Compare any two tire sizes with a to-scale visual diagram, bar charts, and live speedometer simulation.

Calculate tire revolutions per mile/km, rolling circumference, and speedometer error after a size change.

Check tire stretch or pinch for any tire and rim combo — see safe limits and street vs show risk levels.

Estimate prorated tire value and remaining tread life — useful for warranty claims, insurance, and used tire sales.

Calculate BMW tire fitment for any model — compare OEM vs aftermarket sizes, check the xDrive 1% rolling-diameter guideline, M-series staggered specs, and speedometer error.

Complete MX-5 Miata tire calculator for NA, NB, NC, ND — decode sizes, compare stock vs new with speedometer correction, check generation-specific fender clearance, and get track-day recommendations.

Convert tire pressure between PSI and Kilopascals.

OEM tire sizes for Subaru models 2013–2026 from Subaru's specifications. Compare tire size difference with an AWD check and see owner-reported lifted sizes.

Convert kilopascals to PSI for tire pressure, boost/MAP sensor readings, and vacuum. Full conversion chart, vehicle-type pressure guide, and TPMS unit-change instructions.

Compare P-Metric tire dimensions side-by-side.

Compare two tire sizes side-by-side. Diameter, sidewall, speedometer error, revs/mile, and visual chart. P-metric & flotation.

Find the exact diameter difference between two tire sizes. Safety thresholds, speedometer error %, AWD tolerance, and re-gear guidance.

Calculate speedo error from tire size changes.

Convert tire pressure units: PSI and kPa.

Convert between wheel offset and backspace.

See how tire size changes impact effective gear ratio.

Calculate engine RPM at speed based on tire size & gear ratios.

Analyze diameter differences for staggered tire setups.

Calculate scrub radius from SAI, spindle offset, and ET — or estimate the delta from a wheel/spacer swap. Includes drivetrain safety rating.

Calculate total tire height from P-Metric specs.

Check if a tire width is suitable for a given rim width.

Find the aspect ratio for a target tire diameter.

Find max load capacity from load index number.

Find max speed capability from a tire's speed rating letter.

Explore tire options for different wheel sizes.

Assess if a tire is stretched or pinched on a rim.

Estimate a tire's effective radius under load.

Determine tire age from the DOT date code.

Convert tire load range to ply rating and max PSI.

Compare spare tire diameter with primary tires for safety.

Understand Treadwear, Traction, and Temperature ratings.

Estimate inner/outer clearance changes for new setups.

Estimate tire contact patch area from load and pressure.

Calculate tire sidewall height from P-Metric specs.

Calculate tire revolutions per mile and kilometer.

Estimate the internal air volume of a tire.

Calculate total tire diameter from P-Metric specs.

Understand camber and its effects on wear and handling.

Understand caster and its influence on steering stability.

Learn how toe-in/toe-out affects tire wear and stability.

Understand what a tire's UTQG treadwear rating signifies.

Understand a tire's UTQG temperature grade (A, B, or C).

Estimate remaining tread depth and prorated value of a tire.

Convert flotation tire sizes (35×12.50R17, etc.) to P-Metric and get full dimensions: diameter, sidewall, circumference, revs/mile.

Find the recommended rim width range for any tire section width using ETRTO guidelines.

Calculate sidewall height, overall diameter, and circumference for motorcycle tires.

Convert between P-Metric, flotation, and LT tire size formats with full dimension output.

Toyota tire size calculator for Camry, Corolla, RAV4 & 4Runner — compare OEM vs upgrade sizes, check diameter difference and speedometer error.

Calculate BMW tire fitment for any model — compare OEM vs aftermarket sizes, check the xDrive 1% rolling-diameter guideline, M-series staggered specs, and speedometer error.

Check if a BMW xDrive staggered tire setup is safe — compare front vs rear rolling diameter against the commonly cited 1% xDrive guideline and BMW factory pairs, with revs/mile and tread-depth wear check.

Convert metric tire sizes to inches, build P-metric/LT sizes, decode alpha-numeric vintage sizes, and look up load index — all in one free tool.

RAM 1500 & 2500 tire size calculator — compare OEM vs upgrade sizes by trim, check diameter difference, speedometer error, and lift kit requirements.

Mazda3, CX-5 & CX-30 tire size calculator — compare OEM vs plus-size options, check diameter difference and speedometer error instantly.

Decode any Mercedes tire size, compare two sizes with a 4MATIC rolling-diameter check, see factory sizes from Mercedes-Benz USA, and understand MO, MOE, MO1 and MOS tire markings.

Free Audi tire size calculator with factory sizes from Audi USA owner's manuals for A3, A4, A5, A6, RS 6, Q3, Q5, Q7, Q8, R8, Q4 e-tron, Q6 e-tron, Q8 e-tron and e-tron GT. Compare sizes, see the quattro AWD diameter check, speedometer error at 100/130 km/h, ground clearance change and load index check.

Find Tesla-approved tire sizes for Model 3, Y, S, X and Cybertruck from the Tesla Service Manual. Compare sizes, check the speedometer error, and see wheel nut torque. Free tool.

Calculate ATV flotation tire diameter, circumference, revs/mile, speedometer error, and ground clearance vs stock.

Complete Mazda MX-5 Miata tire size calculator for NA, NB, NC, ND. Decode sizes, compare stock vs new with speedometer correction, check generation-specific fender clearance, find sizes by diameter, and get track-day compound recommendations.

Toyota Tacoma tire size calculator for all generations (G1 1995–2004, G2 2005–2015, G3 2016–2023, G4 2024+). Decode sizes, compare stock vs upgrade with speedometer correction, check fender clearance by lift height, and get lift-kit-specific size recommendations. All gens share 6×139.7 bolt pattern.

Lexus tire size calculator for IS, ES, NX, RX, GX, and LX. IS 350 staggered 245/40R18(F)/275/35R18(R). Decode sizes, compare stock vs upgrade with AWD diameter check, and get OEM, summer, winter, and plus-1 setup recommendations.

Ford F-150 tire size calculator for all trims — XLT, Lariat, Raptor, and Lightning EV. 6×135 bolt pattern, OEM fitment, lift-kit clearance, speedometer correction, and Lightning IRS limits.

Calculate total tire height (overall diameter) in inches or mm — from P-metric code, inches direct, or compare two sizes side-by-side. Five modes: metric decode, inches direct, comparison, wheel+tire total, and find by height.

Free Jeep tire size calculator covering Wrangler, Gladiator, Cherokee, and Grand Cherokee. OEM sizes, max fitment by lift height, gear ratio recommendations, crawl ratio, metric ↔ inch conversion, and speedometer correction.

Tractor tire size calculator to compare and convert ag tire sizes: diameter, circumference, rim fit, wheel speed error, MFWD lead and minimum pressure.

Tractor ballast calculator for 2WD, MFWA and 4WD tractors. Target axle weights from PTO power and speed, minimum tire pressure, and liquid ballast gallons.

Convert metric ↔ inch ↔ alpha sizes, look up OEM fitment, compare tires, get terrain pressure recommendations, and check rim compatibility for dirt bikes.

Decode any press-on, pneumatic, or metric forklift tire size. Get full inches & mm dimensions, metric ↔ imperial equivalents, wear thresholds, load index lookup, and brand fitment data for Toyota, Hyster, Yale, Clark, and more.

Calculate golf cart tire dimensions from any size (18×8.5-8, 20×10-10, etc).

Convert any rim size to bead seat diameter in millimeters — includes automotive and bicycle (ETRTO) bead seat diameter charts.

Free truck tire size calculator covering all formats: metric (295/75R22.5), numeric (11R22.5), and flotation (35×12.50R17). Compare sizes, calculate gear ratio recalibration, speedometer correction, load/ply capacity, and view OEM semi truck & lifted truck tire charts.

Calculate tire rolling resistance force (N), power loss (W/kW), and EV range impact for cars, SUVs, and trucks. Crr presets, 7 road surfaces, ISO 28580 dynamic Crr, grade, and aero drag.

Free GMC tire size calculator with OEM lookup by model, year, and trim for Sierra 1500/2500HD/3500HD, Yukon, Canyon, Acadia, Terrain, and Envoy. Includes size comparison, speedometer correction, gear ratio recalibration, lift guide, AT4/AT4X specs, and sidewall decoder.