Atomic Number Calculator — from Any Element Protons, Neutrons & Electrons
Find protons, neutrons, and electrons for any element or isotope. Includes electron configuration, ion calculator, isotope tool, and mini periodic table.
Calculators
Exact Mass Calculator — Monoisotopic Mass & Isotope Abundance
Calculate the exact monoisotopic mass of any molecule from its formula. Uses IUPAC 2021 atomic masses. Results match mass spectrometry M⁺ values.
Isoelectric Point Calculator — pI from Protein or Peptide Sequence
pI from any protein or peptide sequence, view the charge vs pH curve, compute net charge at any pH, and use the MCAT pI formula.
Protein Molecular Weight Calculator — From Sequence or Formula
Calculate protein molecular weight from amino acid sequence or formula. Includes amino acid MW table, extinction coefficient at 260nm, and nmol-to-μg conversion.
Buffer pH Calculator — Henderson-Hasselbalch with Steps
Calculate buffer pH using Henderson-Hasselbalch: pH=pKa+log([A⁻]/[HA]). Find acid-to-base ratio for target pH, buffer capacity, and pH shift from added strong acid or base. pKa table for 20 buffer systems.
Michaelis-Menten Calculator — Km, Vmax, Kcat & Lineweaver-Burk Plot
solve for Km, Vmax, velocity, and substrate concentration, generate Lineweaver-Burk plots from data, calculate kcat and catalytic efficiency, and model enzyme inhibition.
Chi-Square Calculator — Goodness of Fit, Test of Independence & Critical Values
run goodness of fit tests and tests of independence with full (O−E)²/E working tables, p-values, critical values, and Cramér’s V effect size. Supports contingency tables up to 6×6
Arc Length Calculator — Geometry, Calculus & Parametric Curves
find arc length of circle arcs (s=rθ), functions (∫√(1+f’²)dx), parametric and polar curves. Also finds radius from arc length using the sagitta-chord formula.
Standard Atmosphere Calculator — Density Altitude, Pressure & Temperature
Standard atmosphere calculator — find temperature, pressure, density, and speed of sound at any altitude using the ISA model. Includes density altitude calculator, pressure altitude converter, and full ISA reference table from sea level to 80km
Air Properties Calculator — Density, Viscosity & Thermal Conductivity vs Temp
Calculate thermophysical properties of dry air at any temperature and pressure: density, dynamic viscosity, kinematic viscosity, thermal conductivity, and Prandtl number.