Apps
Free online car tools and calculators for DIY mechanics and vehicle owners. Use these apps to estimate fuel costs, compare tire sizes, convert repair units, plan maintenance, check diagnostics, and solve common auto tasks online.
Lease vs Buy Calculator — After-Tax Comparison
Lease vs Buy Calculator Compare leasing vs buying the same vehicle side-by-side over a 3-year window. The calculator includes monthly payment, total cash out, residual....
License Plate & Registration Fees by State
License Plate Format Checker Calculate license plate and registration fees by state. Most US states base registration on weight, value, or a flat fee —....
Lug Nut Torque Guide – Pattern & Spec by Bolt Count
Lug Nut Torque Guide Get the correct lug nut tightening sequence and torque range for your wheel’s bolt count — essential for safe wheel installation.....
Negative Equity Roll-Over — Real Cost of Trade
Negative Equity Roll-Over Calculator See the real cost of rolling negative equity (the amount you owe above your car’s value) into a new auto loan.....
OBD-II Code Lookup — P, B, C & U Code Meaning
OBD-II Code Lookup Look up the meaning of any OBD-II diagnostic trouble code (DTC). Enter a P0xxx, P1xxx, B0xxx, C0xxx, or U0xxx code to see....
OBD2 Code Explainer – Understand P0420 & More
OBD2 Code Structure Explainer Type any OBD-II code to understand its structure — system, generic vs manufacturer, and sub-system — before searching for repair info.....
OBD2 Readiness Monitors – Pass Your Emissions Test
OBD2 Readiness Monitors Guide Understand OBD-II readiness monitors and why ‘not ready’ fails an emissions test — with drive cycle guidance for each monitor. Readiness....
Oil Change Calculator – Next Service Mileage
Oil Change Calculator Calculate your next oil change mileage based on oil type and driving conditions — stay ahead of your service schedule. Oil Change....
Oil Change Verifier — Drained vs Refilled Check
Oil Change Verifier Verify that the oil change shop drained and refilled the correct amount of oil. Comparing drained volume to spec is the simplest....
Oil Viscosity Explained – Decode 5W-30 & More
Oil Viscosity Guide Decode any engine oil grade like 5W-30 — understand the winter and operating viscosity ratings and what they mean for your car.....
