4 free biophysics calculators and tools. Solve real-world biophysics problems instantly with accurate, step-by-step results on ApexCalc.
| Constant | Symbol | Value |
|---|---|---|
| Speed of light | c | 2.99792458×10⁸ |
| Planck's constant | h | 6.62607015×10⁻³‴ |
| Boltzmann constant | kʙ | 1.380649×10⁻²³ |
| Avogadro's number | Nₐ | 6.02214076×10²³ |
| Gravitational constant | G | 6.6743×10⁻¹¹ |
| Gas constant | R | 8.31446 |
| Elementary charge | e | 1.602176634×10⁻¹⁹ |
| Electron mass | mₑ | 9.1093837015×10⁻³¹ |
| Proton mass | mₚ | 1.67262192369×10⁻²⁷ |
| Fine-structure constant | α | 7.2973525693×10⁻³ |
Calculate equilibrium potential for individual ions (Nernst) and resting membrane potential (Goldman-Hodgkin-Katz) from ion concentrations and permeabilities.
Calculate action potential threshold, conduction velocity, and absolute/relative refractory period from axon parameters.
Calculate PK parameters: half-life, volume of distribution, clearance, AUC, Cmax, and Tmax from dose and time-concentration data.
Calculate drug concentration over time for one-, two-, and three-compartment pharmacokinetic models. Predict steady-state concentrations for multiple dosing.