Free online calculator

Voltage divider calculator

Simple

Example Vout = 2.5 V

Formula

V_{out} = V_{in} \times \frac{R_{2}}{R_{1} + R_{2}}

With the default values

2.5 V = 5 V \times \frac{10 kΩ}{10 kΩ + 10 kΩ}

$V_{out} = V_{in} \times \frac{R_{2}}{R_{1} + R_{2}}$

Example Nearest E24: R1=10 kΩ, R2=10 kΩ → Vout = 2.5 V (0.0%)

What you enter

Vin (V)
R1 (Ω)
R2 (Ω)
Nearest buyable value

With load

Example Vout (loaded) = 2.381 V — R2‖RL = 9.091 kΩ

Example Unloaded Vout would be 2.5 V — loading pulls it down by 4.762%

Formula

V_{out} = V_{in} \times \frac{R_{2} ∥ R_{L}}{R_{1} + R_{2} ∥ R_{L}}

With the default values

2.381 V = 5 V \times \frac{9.091 kΩ}{10 kΩ + 9.091 kΩ}

A load draws current from the divider's midpoint, which pulls Vout down from the unloaded (ideal) value — the classic "why did my sensor reading change when I connected it" gotcha.

$V_{out} = V_{in} \times \frac{R_{2} ∥ R_{L}}{R_{1} + R_{2} ∥ R_{L}}$

What you enter

Vin (V)
R1 (Ω)
R2 (Ω)
RL — load resistance (Ω)

Voltage divider calculator

Simple

With load

More calculators