Lap Surface Speed SFPMLapidary Guild
Calculate surface velocity (SFPM) at different points on grinding and polishing laps based on disk diameter and RPM.
Velocity Match Advice
Fine Faceting & Pre-polishing
Explore Additional Utilities
Soil Permeability Converter
Convert coefficient of permeability (hydraulic conductivity) between cm/s, m/day, ft/day, and m/s with soil type drainage classifications.
Zipper Length & Size Converter
Convert zipper lengths between centimeters and inches, and explore standard zipper gauge size applications.
Telescope Magnification Calculator
Calculate telescope magnification, exit pupil, and resolving limit from focal lengths and aperture.
Water discount — full water ↔ reduced water ratio
Optimize water discount levels and water-to-lye concentration ratios to speed up soap curing.
Drug & Supplement Dosage Converter
Convert supplement and drug dosing between milligrams (mg), micrograms (mcg), and International Units (IU) for vitamins A, C, D, and E.
Pipe Flow Rate Calculator
Calculate water flow rate, velocity, and capacity under gravity or pressurized nozzle flow.
Stone size ↔ carat estimator
Estimate carat weight of round, oval, emerald, pear, or marquise cut gemstones from their physical dimensions and specific gravity.
Translation Pages & Pricing Converter
Convert document page count to word and character counts, and calculate translation pricing for multiple languages and target audiences.
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.
Solar Panel Output & Yield Calculator
Calculate daily and annual electricity generation (kWh) based on solar panel capacity (kWp), peak sun hours, and system efficiency losses.
Fabric Width Yardage Converter
Convert fabric yardage requirements between different standard widths like 44 inches and 60 inches.
Stellar Magnitude Converter
Calculate apparent vs. absolute magnitudes of stars and estimate their physical distance.
Servo angle ↔ PWM pulse width
Convert between servo rotation angle in degrees and standard PWM pulse width in microseconds, with continuous rotation presets.
Blood Glucose Converter
Convert blood glucose levels between mmol/L and mg/dL, with diabetic range assessments and HbA1c approximations.
Paper size ↔ finished model size — origami scaling
Determine required starting paper square dimensions to fold specific final 3D origami model sizes.
Container volume ↔ wax fill weight — density calculation
Convert liquid container water volumes to actual solid wax weights using correct wax specific gravity ratios.
NPK Fertilizer Blend Designer
Calculate exact commercial fertilizer weights (Nitrogen, Phosphate, Potash) required to hit crop nutrient targets.
Latency ↔ distance — speed of light in fiber
Calculate propagation delay and round-trip time (RTT) for signals traversing fiber optic, copper, air, or vacuum.
Oxygen Saturation & PaO2 Converter
Convert blood oxygen saturation (SpO2) to partial pressure of oxygen (PaO2) using the clinical Severinghaus-Ellis model.
Leather weight — oz ↔ mm thickness
Convert leather weights in ounces to exact millimeter or fractional inch thickness. View target usage categories.