For when the answer is "it depends on the schedule, the standard, and three footnotes" — and you need the right number now.
Each conversion has its own page — formula, examples, reference values, and a live converter. The pages below get the deepest treatment; over 100 more pairs are auto-generated for direct linking.
Over 100 conversion-pair pages in total. Don't see what you need? The universal converter above handles every pair.
Each cheat sheet is a hand-laid-out reference: clean tables, footnoted edge cases, citations to the named standard, one-click print, one-click PDF. Pin it to the wall, paste it in a wiki, share it with a colleague.
Diameter, area, resistance per 1000 ft, ampacity at 60/75/90 °C insulation. Sourced from NEC.
Fractional, decimal, letter, number, metric — with the closest cross-match column.
UNC, UNF, metric coarse, metric fine — with recommended tap drill and clearance hole.
Grade 2 / 5 / 8 imperial, 8.8 / 10.9 / 12.9 metric. Dry, lubricated, and anti-seize values.
NPS, ISO/DN, PEX, copper Type K/L/M — with schedule, ID/OD, and applications.
4-band, 5-band, 6-band with tolerance and temperature coefficient. Interactive decoder.
3-digit, 4-digit, and EIA-96 codes for surface-mount resistors. Full lookup table.
Steel, aluminum, copper — they're all different. Thickness in inches and mm.
h7, H7, k6, n6 and the rest — with actual dimensions for common nominal sizes.
Common sound levels with NIOSH exposure limits and hearing-damage thresholds.
SAE and metric sockets, sorted by size with closest cross-match column.
ISO 216 A & B series, US ANSI series, plus bleed and safe area for print design.
Cups ↔ mL, oven F/C/gas mark, USDA safe cooking temperatures.
3-digit codes, tolerance letters, ceramic temp coefficients, polarity markings.
J, K, T, E, N, R, S, B — range, accuracy, color codes (US ANSI and IEC).
Absolute zero to surface of the sun. Cooking, body, weather, melting points.
Tire, blood, hydraulic, scuba, deep-sea — across psi, bar, kPa, mmHg.
Real-world forces from grain of sand to Saturn V thrust, plus structural loads.
CFM capacity vs round duct diameter, equivalent rectangular sizes, residential rules.
Dash numbers, ID, cross-section across 0xx through 4xx series. Material guide.
6000/6200/6300 series ball bearings — bore, OD, width, and the number decoder.
A36, A572, A992, 4140, 304, 316 — yield, tensile, and typical applications.
Seven recycling codes plus engineering plastics: ABS, PC, nylon, PTFE, PEEK.
Aperture, shutter, ISO stops. Sunny 16, scene reference, exposure triangle.
US men's, women's, kids', UK, EU, cm. With the brand-variation caveats.
Pilot, clearance, countersink for #4-#14 wood screws and lag screws.
Multi-input lookups that Google's answer box can't render and AI chat can't reliably compute. Each one is deterministic, sourced, and shows its work.
Pick the right AWG given amperage, run length, voltage, and allowable drop. NEC ampacity tables.
Best pilot, tap, and clearance hole given screw size and material (wood, metal, plastic).
Recommended torque given bolt grade, diameter, lubrication, and target preload.
Room heat loss given wall area, R-values, indoor/outdoor temperature difference.
Friction loss for a given flow, fluid, pipe size, and length. Darcy–Weisbach.
Lumber volume with waste factor. Common nominal vs actual sizes built in.
Slab, footing, post hole, or round column. With waste factor and ready-mix yard rounding.
Two-resistor divider — solve for Vout, R1, or R2. With E12/E24/E96 closest-value suggestions.
Pick the right resistor given supply voltage, LED Vf, and target current. Power dissipation included.
Convert between RPM and SFM for lathe and mill work. Material presets for HSS and carbide tooling.
Optimal tilt for fixed PV panels by latitude. Year-round, seasonal, and two-season strategies.
Round and rectangular duct sizes for given CFM at standard friction rate. ASHRAE-based.
Simply-supported wood or steel beam with UDL. Bending, shear, deflection checks.
psi, bar, Pa, mmHg, atm — when to use which, and why the same physical thing has a dozen names.
Why "smaller number = bigger wire," how AWG relates to mm², and the gotchas when sourcing internationally.
Nominal vs actual diameter, schedule numbers, and why a "1-inch" pipe isn't one inch.
The distinction that breaks first-year engineering homework — and the conversions that follow.
Every value cites its standard — NEC, ASTM, ISO, IEC. Use it in a spec; it's auditable.
Every cheat sheet has a one-click print mode designed for paper, not just for screen.
No data leaves your device. No sign-up. No tracking beyond aggregate page views.
Designed for looking things up on a phone in the field, not just from a desktop.