Dissociation Constant (Kd) Calculator

Calculate Kd from equilibrium concentrations, Ka, kinetic rates, or thermodynamic data

Calculation Method

Select Method

Free Receptor [R] (M)

Free Ligand [L] (M)

Complex [RL] (M)

Dissociation Constant (Kd)

1111.111 mM

1.1111e+0 M

Ka

9.000e-1 M^-1

Delta G

0.26 kJ/mol

Calculation

Kd = [R][L]/[RL] = (5 x 10)/45

Kd Interpretation

Kd = concentration at 50% saturation
Lower Kd = tighter binding
Kd = [R][L]/[RL] at equilibrium