International Hat Size Matcher
Convert hat dimensions across US, UK, and European standards.
Fitted Hat Size guidelines: Classic fedoras, panamas, and baseball caps are sized in US/UK fractions. Take head circumferences across the forehead and just above your ears.
Medium (M)
Explore Additional Utilities
Wire feed speed ↔ amperage — MIG welding settings
Calculate MIG wire feed speed (WFS) and matching amperage. Includes gas recommendations and presets for steel, stainless, and aluminum.
Twist per inch (TPI) — spinning wheel flyer ratio ↔ speed
Calculate twists per inch (TPI) based on flyer ratio, treadles per minute, and fiber intake rate.
Superfat percentage — excess oil ↔ skin conditioning level
Calculate excess unsaponified superfat oils and skin-conditioning moisture metrics.
Fabric Width Yardage Converter
Convert fabric yardage requirements between different standard widths like 44 inches and 60 inches.
Jewel count ↔ movement quality indicator
Explore movement bearing counts from 1 to 30+ jewels. See where rubies are placed and how they reduce mechanical friction.
Karat purity (Karat ↔ Fineness ↔ % gold)
Convert gold purity levels between Karat values, parts-per-thousand millesimal fineness, and pure gold percentage.
Thread length — stitch count ↔ thread needed
Calculate thread length needed for saddle stitching based on stitch line length, leather thickness, and spacing density.
Stellar Magnitude Converter
Calculate apparent vs. absolute magnitudes of stars and estimate their physical distance.
IV Drip Rate (Drops/min ↔ mL/hour)
Convert IV flow rates between mL/hour and drops/minute (gtt/min) for any drop factor, with real-time dripping rate animation.
Blood Glucose Converter
Convert blood glucose levels between mmol/L and mg/dL, with diabetic range assessments and HbA1c approximations.
Carbon Footprint Calculator
Convert between distance driven (km or miles) and greenhouse gas emissions (kg CO2) across various vehicle fuel types and efficiencies.
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.
Sidereal Time Converter
Convert between standard Solar Time and Sidereal Time based on your longitude.
Ballistic coefficient ↔ drag — projectile performance
Calculate bullet Sectional Density (SD) and Ballistic Coefficient (BC) using projectile weight, caliber, and form factor.
Paper size ↔ finished model size — origami scaling
Determine required starting paper square dimensions to fold specific final 3D origami model sizes.
Melt point — wax type ↔ degrees Celsius ↔ Fahrenheit
Analyze melt points, fragrance addition temperatures, and pour temperatures for different waxes.
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.
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.
Brick Count Estimator
Calculate bricks, mortar volume, sand, and cement needed for masonry walls.
Dissolved oxygen — mg/L ↔ % saturation at temperature
Convert between DO mg/L and % saturation. Analyze solubility boundaries based on water temperature and salinity.