Case Size & Lug GuideWatchmaking & Horology
Analyze watch case diameter proportions, lug-to-lug spans, and find the corresponding standard strap lug-width sizes.
Calculations derived from Swiss and Japanese chronometric engineering standards. Always refer to your watch movement user manual to avoid shearing delicate calendar teeth or stripping winding stems.
Perfect classic mechanical sizing. Balanced case footprint for supreme wear comfort.
Explore Additional Utilities
Grade converter — Yosemite ↔ French ↔ UIAA ↔ Australian
Convert climbing difficulty grades across Yosemite Decimal System (YDS), French, UIAA, Ewbank, and bouldering scales.
Carat weight ↔ grams
Convert between diamond or gemstone carats, metric grams, grains, and points of gem weight.
Dewpoint & Relative Humidity Calculator
Calculate dewpoint, relative humidity, or air temperature using the Magnus-Tetens formula.
Hallmark converter (UK date letters ↔ year)
Decode historic and modern UK silver, gold, and platinum hallmarks, converting assay office date letters to exact production years.
Muzzle velocity — fps ↔ m/s ↔ km/h
Convert velocities between fps, m/s, and km/h. Calculate muzzle kinetic energy in Joules and Foot-Pounds.
Twist rate — caliber ↔ bullet length → stabilization
Calculate the optimal barrel rifling twist rate needed to stabilize a bullet of a given length, caliber, and velocity.
True wind ↔ apparent wind
Calculate apparent wind speed and angle from true wind speed, sailing angle, and boat speed (or vice versa).
Stepper motor steps (degrees ↔ steps ↔ microsteps)
Convert between motor rotation angles in degrees, physical steps, and microsteps based on step angle and microstepping resolution.
USCS Soil Classification Solver
Classify soil type under the Unified Soil Classification System (USCS) using sieve analysis and Atterberg limits.
Servo angle ↔ PWM pulse width
Convert between servo rotation angle in degrees and standard PWM pulse width in microseconds, with continuous rotation presets.
Watch beat rate — BPH ↔ Hz ↔ vibrations per hour
Convert mechanical watch balance wheel frequencies between Beats Per Hour (BPH), Vibrations Per Hour, and Hertz (Hz).
Layer height ↔ print time estimator
Estimate 3D print duration changes and total layer counts when switching layer heights and print speeds.
Bullet drop — distance ↔ inches ↔ cm at given range
Estimate bullet drop trajectories over distance based on muzzle velocity, projectile mass, and gravitational pull.
Wet folding moisture — paper weight ↔ water absorption
Calculate optimal water moisture weight to apply based on paper GSM and wood fiber absorption capacity.
Cosmic Distance Converter
Convert huge distances across Light Years, Parsecs, Astronomical Units, and Kilometers.
Barometric Pressure Tendency Analyzer
Analyze changes in barometric pressure over time to predict short-term local weather trends.
Pace, Speed & Time Converter
Convert between different running paces and speeds (min/km, min/mile, km/h, mph) and predict race times.
pH Acid/Base Index
Evaluate hydrogen ion concentrations and check acidic or alkaline levels using pH logarithmic scales.
Glaze specific gravity ↔ pint weight — glaze consistency
Convert glaze liquid specific gravities to US/Imperial pint weights and calculate suspended dry material volumes.
Water Footprint & Virtual Water Calculator
Estimate virtual water consumption based on diet choices, household activities, and direct/indirect product footprints.