Math & Numbers
Convert torque (moment of force) between N·m (SI base), lbf·ft (pound-foot), kgf·m (kilogram-force-metre), and lbf·in (pound-inch). Factors based on standard gravity g₀ = 9.80665 m/s² and 1 lbf = 4.4482216152605 N. Converts via N·m to the target unit and also lists the equivalent value in all four units for reference. Used for mechanical specs, automotive, and fastener tightening torque.
torque-unit-converterMath & Numbers
Linear and volumetric thermal expansion of an isotropic material. Linear: ΔL = α·L₀·ΔT, L₁ = L₀·(1+α·ΔT). Volumetric: ΔV = 3α·V₀·ΔT (β = 3α for isotropic solids). Built-in typical α for carbon/alloy steel, aluminum, copper, austenitic stainless, titanium and glass, plus custom. ΔT in K or °C, length in mm, volume in mm³.
thermal-expansion-calculatorMath & Numbers
Thermal stress in a fully constrained member under a uniform temperature change: σ_th = E·α·ΔT. Built-in typical Young's modulus E and expansion coefficient α for carbon/alloy steel, aluminum, copper, austenitic stainless and titanium, plus custom values. ΔT in K or °C (same magnitude), result in MPa. Heating (ΔT>0) → compressive stress in the member.
thermal-stress-calculatorMath & Numbers
Compute the thermal comfort indices PMV (Predicted Mean Vote, −3 cold..+3 hot) and PPD (Predicted Percentage Dissatisfied, %) per ISO 7730 / ASHRAE 55, using the Fanger equations. Inputs: air temperature Ta, mean radiant temperature Tr, relative air velocity v_ar, relative humidity φ, metabolic rate M (met; 1 met = 58.2 W/m²), clothing insulation Icl (clo; 1 clo = 0.155 m²·K/W), and external work W (defaults to 0). The clothing surface temperature Tcl is solved iteratively. Returns a 7-level ASHRAE sensation label.
thermal-comfort-pmvGeography
Estimate spring/neap tide forcing and lunar-distance amplification with a transparent offline planning model.
tide-and-lunar-distance-predictorMath & Numbers
Calculate active, reactive, and apparent power for a balanced three-phase system: S=√3·U·I, P=√3·U·I·cosφ, Q=√3·U·I·sinφ. Also returns the power-factor angle φ and verifies the power triangle.
three-phase-power-calculatorMedia
Convert a selected TIFF page to verified 16-bit-per-channel grayscale, RGB, or RGBA PNG.
tiff-to-16bit-pngMath & Numbers
Reflect an impedance through an ideal transformer: Z' = a²·Z, where a = N₁/N₂. Supports secondary→primary and primary→secondary directions; a can be given directly or derived from N₁/N₂. Also returns admittance Y and reflected admittance.
transformer-impedance-transferMath & Numbers
Ideal transformer ratio: a = N₁/N₂ = V₁/V₂ = I₂/I₁. Given turns, voltage, or current on either side, compute a and the corresponding voltage/current on the other side; verifies V₁·I₁ = V₂·I₂.
transformer-turns-ratioMath & Numbers
Convert common physical, chemistry, cooking, medical, and information units with the formula and dimensional analysis visible.
unit-converter-with-formulaFinance
Compare supermarket product prices by normalizing them to a common unit (per 100g, per liter, per piece, etc.). Enter products as 'name, price, quantity, unit' per line. Ranks from cheapest to most expensive per unit and shows savings vs the most expensive option.
unit-price-calculatorGames
Test your knowledge with a trivia quiz. Random questions from a built-in English bank across science, history, geography, and general topics. Pick 1 of 4; get your score and accuracy at the end.
trivia-quiz