Goldman-Hodgkin-Katz (GHK) Equation Calculator

Calculated equilibrium potentials (V_eq) for K⁺, Na⁺, and Cl^- (read-only values)

V_K
mV

V_Na
mV

V_Cl
mV

Calculated electrochemical driving forces (V_DF = V_m − V_eq) (read-only values)

V_DF,K
mV

V_DF,Na
mV

V_DF,Cl
mV

Units: fM = 1e-15 M, pM = 1e-12 M, nM = 1e-9 M, μM = 1e-6 M, mM = 1e-3 M, M = 1 M.
T must be in Kelvin. Outputs always in mV. Enter V_m to see driving forces. If V_m is blank, the GHK equation is used to calculate V_m.

What Is the Electrochemical Driving Force Calculator?

This calculator lets users estimate the electrochemical driving force (V_DF) by using a simple relation between membrane potential and equilibrium potential. It's based on the formula — V_DF = V_m − V_eq — which shows how far from equilibrium an ion is, inside vs outside the cell.

It can also calculate the missing value if any one of these is unknown. You just leave that field empty. The result also shows whether ions go in or out, depending on their type and sign of the driving force. Really helpful if ur studying ion movement, resting potentials, or passive transport in neurobiology or cell physiology.

How To Use This Calculator

You gotta fill two of the following fields:

Membrane potential (V_m) — usually negative, like -70 mV
Equilibrium potential (V_eq) — depends on ion type, like -90 or +60 mV
Driving force (V_DF) — shows how strong the gradient is, like +20 mV

Then select the unit — either mV or V. It auto converts all entries to volts internally, so don’t worry if you mix up units. Also choose whether you're dealing with cation or anion, 'cause that affects flow direction.

How It Works

The formula is basic:
V_DF = V_m − V_eq
If V_DF is zero, there's no net movement. But when it's positive or negative, stuff happens.

For cations:
→ +V_DF means they exit (efflux)
→ −V_DF means they enter (influx)

For anions:
→ +V_DF means influx
→ −V_DF means efflux

All fields accept decimal values. Just don’t use scientific notation like 1×10^-3, type 0.001 instead. Tool shows direction text after solving — like “Anion moves IN” or “No net movement”.

Tool Features

Instant solve for any one value (V_m, V_eq, or V_DF)
mV and V input supported
Handles cations and anions separately
Direction of flow output shown automatically
Formula displayed below result for clarity

This thing's perfect for biology students, med folks, and neuro people trying to check which way K⁺, Cl⁻, Na⁺ or Ca²⁺ wanna go. Also great for exam prep or lab calc.