About SocketConversion.com

SocketConversion.com is a free reference for mechanics, technicians, machinists, and engineers who work across metric and SAE measurement systems. We publish socket conversion charts, wrench size tables, bolt charts, drill and tap drill references, thread standards, and live calculators that update as you type, with no submit buttons and no waiting.

The site is independent and not affiliated with any tool manufacturer. Every conversion in our tables comes from a direct calculation against the international inch, defined as exactly 25.4mm since 1959, cross-checked against published engineering standards including ANSI/ASME, ISO, and DIN. We don't shorten the math, and we don't round prematurely. Every chart states an interchangeability rating so a reader knows not just the closest size, but whether it's genuinely safe to use in place of the exact one.

The interchangeability bands used across this site (Highly Interchangeable at 0.005 inch or less, Use with Caution up to 0.015 inch, Not Recommended beyond that) reflect tolerance guidance commonly cited in workshop and engineering reference material, not a marketing claim. Where a size substitution carries real risk, such as torque-critical fasteners, soft materials like brass and aluminum, or impact-wrench use, the relevant page says so directly rather than leaving it implied.

Coverage spans automotive repair, small engine work, industrial maintenance, fabrication, machining, and general workshop use. If you'd like to suggest a correction or a new chart, our contact page is open. Start at the homepage, or jump straight to the wrench size chart or bolt size chart.