Discount a future lump sum or an annuity back to today's value (PV). Supports lump-sum and annuity cash flows, multiple compounding frequencies, a present-value decay curve, and a per-period breakdown. PV = FV / (1+r)^n for a lump sum.

Finance

Retirement Calculator

Two-phase retirement model: an accumulation phase (current age to retirement, with monthly contributions and compound growth) and a withdrawal phase (retirement to life expectancy, nest egg grows at a conservative rate while inflation-adjusted withdrawals are taken out). Reports whether the nest egg lasts, real purchasing power, and any shortfall.

Math & Numbers

Half-Life Calculator

Exponential decay for radioactive isotopes and drugs: remaining amount, derived half-life, time to target, or steady-state accumulation. Uses N(t) = N0·e^(-λt).

Math & Numbers

Pendulum Period Calculator (T = 2π√(L/g))

Compute period, length, or gravity of a simple pendulum, plus amplitude-based peak speed and energy

Math & Numbers

Pressure Calculator & Converter (P=F/A, Pa/kPa/bar/atm/psi)

Solve pressure, force, or area from P=F/A, and convert between Pa, kPa, MPa, bar, atm, psi, Torr, inHg, kgf/cm²

Math & Numbers

Wavelength Calculator (λ = v/f, period, wave number, angular frequency)

Solve wavelength, frequency, or wave speed from v=f·λ, with derived period, angular frequency, wave number, and photon energy

Math & Numbers

Potential Energy Calculator (PE = mgh)

Compute gravitational potential energy, mass, or height from the other two, with impact velocity

Math & Numbers

Projectile Motion Calculator (Range, Height, Time)

Compute range, max height, flight time, and the full trajectory of a projectile given speed, angle, and optional initial height

Math & Numbers

Resistor Series / Parallel Calculator

Combine resistors in series, parallel, or an arbitrary +/| expression, with per-resistor voltage and power

Math & Numbers

Voltage Divider Calculator

Calculate divider output voltage, solve for R1 or R2, and evaluate load effects with a circuit diagram

Math & Numbers

Cable Voltage Drop Calculator

Compute cable voltage drop from current, length, conductor size (AWG/mm²) and material, for DC, single-phase and three-phase circuits

Math & Numbers

Thermodynamics (Gibbs Free Energy) Calculator

Calculate Gibbs free energy ΔG = ΔH − TΔS, reaction spontaneity, equilibrium temperature, and equilibrium constant K.