About WrenchRig

Free, accurate automotive calculators built for the people who actually turn wrenches.

🔧 What WrenchRig Is

WrenchRig is a free suite of automotive calculators designed for mechanics, fabricators, fleet managers, and car enthusiasts who need reliable numbers - fast. Whether you're comparing tire sizes in the shop, calculating fuel costs for a fleet, converting torque specs on a build, or figuring out the right coolant mix for winter, WrenchRig gives you the answer without ads-first bloat or paywalls.

Every tool runs entirely in your browser. We don't store your inputs, don't require an account, and don't gate features behind subscriptions. You open the page, enter your numbers, and get your answer.

🎯 Why We Built This

We got tired of searching for basic automotive calculations and landing on pages stuffed with pop-ups, wrong math, and generic content written by people who've never held a torque wrench. The automotive industry deserves better tools.

WrenchRig exists to be the go-to reference for automotive math - the kind of site a shop tech bookmarks, a fleet manager keeps open in a tab, and a weekend builder sends to their buddy.

📐 Our Accuracy Standards

Accuracy isn't optional when professionals rely on your numbers. Here's how we ensure our calculators are trustworthy:

Formula Verification

Every formula is cross-referenced against authoritative sources - SAE standards, engineering textbooks, NIST conversion factors, IRS published rates, and ASTM specifications. We don't guess. We cite.

Real-World Validation

Calculators are tested against known real-world values. Our engine displacement calculator is validated against published OEM specs (like GM's 5.7L LS1 = 5,665cc). Our torque conversion factors match NIST Handbook 44 to the published decimal places.

Automated Monthly Testing

Every tool is automatically tested monthly with a suite of known inputs and expected outputs. If any calculation drifts or a code change introduces an error, we catch it before a user does. Every tool in our registry is tested - nothing slips through.

Transparent Methodology

Each tool page includes the formulas used, step-by-step explanations, and references to relevant standards. We don't hide behind a black box - we show our work so you can verify it yourself.

🛠️ What We Cover

WrenchRig currently offers calculators across these categories:

  • Tires & Wheels - Tire size comparison, speedometer correction, wheel offset, bolt pattern, tire pressure temperature adjustment
  • Fuel & Cost - Fuel cost, MPG, cost per mile
  • Engine & Performance - Engine displacement, compression ratio, HP/torque conversion, 0-60 time estimation
  • Drivetrain - Gear ratio
  • Shop & Repair - Torque conversion, coolant mix ratio, two-stroke oil mix ratio

We're adding new tools regularly. If there's a calculator you need, let us know at hello@wrenchrig.com.

💰 How We Keep It Free

WrenchRig is supported by two revenue sources:

  • Google AdSense - Display ads that appear on our pages
  • Amazon Associates - We recommend relevant tools and products on each calculator page. When you buy through our links, we earn a small commission at no extra cost to you. We only recommend products we'd actually use in the shop.

These revenue streams allow us to keep every tool completely free, with no accounts or paywalls - ever.

📬 Contact

Questions, feedback, tool requests, or found a bug? We want to hear from you.

Email: hello@wrenchrig.com