DIY Auto Lookup
Mechanic toolbox

Technician Reference Tools

Quick conversions, shop math, and repair references for common automotive work. Use these helpers for planning, then verify safety-critical specs with vehicle-specific service information.

Open Converters View Tables
Fast shop math

Conversion Tools

Convert the measurements technicians reach for most: wrench sizes, torque, pressure, volume, length, and electrical basics.

Metric to SAE Wrench Size

Find the closest standard wrench/socket size for a metric fastener.

mm

Torque Converter

Convert between ft-lb, in-lb, and N-m before setting the torque wrench.

Pressure Converter

Convert tire, fuel, compression, or A/C pressure readings.

Fluid Volume Converter

Convert oil, coolant, gear oil, and ATF quantities.

Length Converter

Convert measurements used for ride height, brake parts, and clearances.

Electrical Formula Helper

Use Ohm's law for quick voltage, amperage, resistance, and wattage math.

Reference tables

Shop Reference

Common references for hand tools, tire service, batteries, thread pitch, and fluids.

Common Metric to SAE

MetricClosest SAENote

Thread Pitch Reminders

  • M6: common pitch 1.0 mm
  • M8: common pitch 1.25 mm
  • M10: common pitch 1.25 or 1.5 mm
  • M12: common pitch 1.25, 1.5, or 1.75 mm
  • Rule: start bolts by hand and match old hardware before forcing threads.

Battery Quick Checks

  • 12.6 V: fully charged engine off
  • 12.2 V: partially discharged
  • Below 12.0 V: charge and test before diagnosing modules
  • 13.5-14.8 V: typical charging voltage while running
  • Warning: verify battery monitor reset requirements on newer vehicles.

Tire and Wheel Reminders

  • Set tire pressure cold using the door-jamb label, not the tire sidewall max.
  • Torque lug nuts in a star/cross pattern with a torque wrench.
  • Recheck lug torque after a short drive when wheels were removed.
  • Inspect for tire date code, sidewall bubbles, uneven wear, and missing wheel weights.

Fluid Handling Reminders

  • Never open a hot cooling system.
  • Use the exact transmission fluid type and fill-level procedure.
  • Brake fluid absorbs moisture; use fresh sealed fluid.
  • Gear oil smell is strong; use gloves and clean spills quickly.

Quick Formula Sheet

  • Voltage: V = A x Ohms
  • Amps: A = V / Ohms
  • Resistance: Ohms = V / A
  • Watts: W = V x A
  • Torque: 1 ft-lb = 12 in-lb = 1.3558 N-m