Scientific Tools

Calculate population growth with exponential and logistic models — solve for N, growth rate r, time, or N₀ with projections and doubling time. Free, browser-based.

Calculate star distance from parallax or magnitude. Convert between parsecs, light-years, AU, and km. Free, instant, browser-based astronomy tool.

Calculate blackbody peak wavelength, Stefan–Boltzmann flux, and Planck spectral radiance from temperature. Wien's law and σT⁴. Free, browser-based physics tool.

Convert astronomical units (AU) to light-years, parsecs, kilometers, meters, and miles. Enter any distance and get instant conversions with formulas. Free, browser-based.

Assess exoplanet habitability with habitable zone, equilibrium temperature, and Earth Similarity Index (ESI). Presets for Earth, Proxima b, and Kepler-186f. Free, browser-based.

Calculate Young's modulus E = σ/ε from stress and strain, or from a tensile test (force, area, elongation). Convert between GPa, MPa, Msi, ksi, and psi. Compare to common material references. Free, browser-based.

Calculate linear, area, and volume thermal expansion from temperature change. ΔL = αL₀ΔT, ΔA = 2αA₀ΔT, ΔV = 3αV₀ΔT. Bimaterial gap mode for differential expansion between two materials. Material presets for steel, aluminum, concrete, and copper. Metric and imperial units. Free, browser-based.

Calculate gear ratio, output RPM, and torque multiplier for spur gear trains. Single-stage, compound 2-stage, RPM solver, and tooth-count finder for target ratios. Enter driver and driven tooth counts — get speed reduction and ideal torque gain. Free, browser-based.

Calculate bolt tightening torque, clamp preload, and nut factor K. Modes: torque from preload (T = KDF), preload from torque, recommended torque from proof load and bolt grade, and nut-factor solver. Metric (mm, kN, N·m) and imperial (in, lbf, lbf·ft) with M6–M24 and Grade 5/8 presets. Free, browser-based.

Plan lab dilutions with pipette volumes, 1:N ratio dilutions, and serial dilution schemes. Get C₁V₁=C₂V₂ stock aliquots, sample and diluent volumes, and step-by-step bench procedures in µL, mL, or L. Free, browser-based.

Molar mass calculator free — parse chemical formulas like H2O or Ca(OH)2 and get g/mol with an element breakdown. Browser-based, instant, no signup.

Mole calculator free — convert between grams, moles, and particles using molar mass. Instant chemistry stoichiometry in your browser, no signup.