Lux & Foot-Candles Photometry
Calculate architectural light levels, illuminance indexes, and foot-candle units.
Explore Additional Utilities
Battery capacity — Ah ↔ Wh ↔ days of autonomy
Convert between Amp-hours (Ah) and Watt-hours (Wh) and calculate battery bank backup days of autonomy based on loads.
Stellar Magnitude Converter
Calculate apparent vs. absolute magnitudes of stars and estimate their physical distance.
SO2 emission rate — flux ↔ tons per day
Convert sulfur dioxide degassing rate from tons per day to metric mass rates.
Drawing out ratio — starting thickness ↔ final length
Estimate expanded length when forging down the cross-section thickness of hot steel bars under conservation of volume.
Gas mix — O2 % ↔ depth limit — MOD calculation
Calculate the Maximum Operating Depth (MOD) and partial pressure of oxygen (PPO2) for nitrox and air diving.
Signature count — total pages ↔ sheets per signature
Divide book blocks into balanced signatures and calculate standard folded sheet configurations.
Forge temperature — color ↔ degrees Celsius — black to white heat
Reference forging heat ranges with equivalent temperature degrees and workability levels.
Color rod weight ↔ color intensity in clear glass
Calculate required color rod weights to achieve target color intensity saturation levels in clear glass gathers.
Speed to fly — polar curve ↔ McCready interthermal speed
Calculate the optimum speed to fly between thermals based on the glider polar curve, expected next thermal climb rate, and headwind/sink.
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.
Wraps per inch (WPI) ↔ yarn weight category
Convert wraps per inch (WPI) count to standard yarn weight categories, and find recommended knitting needle/crochet hook sizes.
Contour interval ↔ slope gradient — terrain steepness
Calculate terrain steepness, percentage grade, and slope angles using contour line spacing and map contour intervals.
Wind window — apparent wind angle ↔ power zone position
Determine apparent wind speed, angle, and optimal power zone placement.
Angular diameter — object size + distance → arcseconds
Calculate celestial body angular diameter in arcseconds, arcminutes, or degrees.
Final glide calculator — height + glide ratio → reach distance
Analyze safety margins, required arrival altitude, wind impact, and distance reachable for your glider final glide phase.
Kite size — wind speed ↔ rider weight
Calculate the recommended kite size in square meters (m²) based on rider weight and wind speed.
Gemstone rough weight ↔ finished carat yield
Estimate finished faceted carat weight and material yield percentages of raw gemstone rough.
Carat weight ↔ grams
Convert between diamond or gemstone carats, metric grams, grains, and points of gem weight.
Diopter ↔ Focal Length Converter
Convert between lens diopters and focal length in meters, millimeters, or inches, and calculate eyeglass lens power requirements.
Ink viscosity — temperature ↔ consistency adjustment
Adjust oil-based printmaking inks for stiffness, tack, and temperature variations using modifiers and plate oils.