Earthquake Magnitude (Richter ↔ Moment)
Convert and compare earthquake magnitude scales, calculating shaking amplitude ratios, energy release equivalents (TNT), and felt effects.
Explore Additional Utilities
Barometric Altimeter Settings
Calibrate pressure settings between QNH and QFE based on airfield elevation and temperature.
Board size — rider weight ↔ wind conditions → liters
Calculate optimal board size, volume, and dimensions for your riding style.
Carbon Footprint Calculator
Convert between distance driven (km or miles) and greenhouse gas emissions (kg CO2) across various vehicle fuel types and efficiencies.
Crown position ↔ function — hand setting vs winding
Map out the mechanical state and winding functions of crowns at positions 0, 1, and 2, including quickset dates and hacking.
Legal Billable Hours Estimator
Convert word count of legal drafting documents to estimated billable hours based on complexity and billing rates.
Thread Weight Converter
Convert between different thread sizing standards including Tex, Denier, and Number English (Ne).
Telescope Magnification Calculator
Calculate telescope magnification, exit pupil, and resolving limit from focal lengths and aperture.
Pace, Speed & Time Converter
Convert between different running paces and speeds (min/km, min/mile, km/h, mph) and predict race times.
Wind Turbine Power Generator
Estimate power output (watts) of a wind turbine based on wind speed, rotor diameter, blade sweep area, and aerodynamic power coefficients.
Oxygen Saturation & PaO2 Converter
Convert blood oxygen saturation (SpO2) to partial pressure of oxygen (PaO2) using the clinical Severinghaus-Ellis model.
Sidereal Time Converter
Convert between standard Solar Time and Sidereal Time based on your longitude.
Drug Concentration Converter
Convert pharmaceutical concentrations between % w/v, mg/mL, and mol/L using substance molecular weight presets.
Mohs Hardness & Scratch Resistance
Compare minerals, absolute hardness values, and scratch interactions using the classic 1-10 Mohs scale and Knoop indentation hardness.
Gear ratio (input RPM ↔ output RPM ↔ torque)
Calculate gear ratios and convert input RPM and torque to output values based on compound single or double-stage tooth configurations.
Cloud Base Height Estimator
Estimate cloud condensation levels and cloud base height based on temperature and dewpoint spreads.
eGFR Kidney Function Calculator
Calculate Estimated Glomerular Filtration Rate (eGFR) using the modern CKD-EPI (2021) equation to evaluate kidney stages.
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.
Soil Plasticity Index Calculator
Calculate Plasticity Index (PI) from Liquid Limit (LL) and Plastic Limit (PL), and interpret soil state using the Atterberg limits chart.
Layer height ↔ print time estimator
Estimate 3D print duration changes and total layer counts when switching layer heights and print speeds.
Paint Coverage Calculator
Estimate the gallons or liters of paint needed based on area and number of coats.