Metric equivalents next to imperial measurements on McMaster-Carr, plus dark and beige themes.
Users
36
0 in 30 days
Rating
5.0 / 5
unchanged in 30 days
Ratings
1
0 in 30 days
Store rank
#123K
#103K among extensions
Version
1.8.1
updated 24 Jul 2026
Users
monthly, 4 months
Latest, 20 Oct 2026:36 usersMove the mouse over the chart for any month
Ratings count
monthly, 4 months
Latest, 20 Oct 2026:1 ratingsMove the mouse over the chart for any month
The Chrome Web Store rounds user counts down to the leading digit, so the user line moves in steps. The ratings count is exact and is the better signal of real adoption.
About McMetric
Tired of mentally converting inches while browsing McMaster-Carr? McMetric annotates every imperial measurement with its metric equivalent, inline and in green, so 3/4" reads 3/4" (19.05 mm).
What gets converted: • Inches (fractions, mixed numbers, decimals) → mm or m • Feet → m • Pounds → kg, or Newtons when the context is a load/force rating • lbf → N • Ounces → g • psi → bar, or MPa for tensile strengths • °F → °C
Works everywhere on mcmaster.com: product detail pages, catalog listing tables (including columns whose unit lives in the header, like "Working Load, lb."), and sidebar filters. Thread callouts like 1/4"-20 are left untouched — they're size designations, not dimensions.
Toggle annotations on or off from the toolbar popup. No accounts, no tracking, no data collection. Runs only on mcmaster.com.
V1.2: torque and drill-gauge conversions, per-unit preferences pane
V1.7.1: themes added: dark mode and beige mode, bug fixes
V1.8.1: improved dark theme, spring rate & No. # screw conversions, bug fixes