Voltage Divider Calculator

Find your output voltage in seconds. Enter Vin, R1 and R2 to get the divider output, current and power — or flip to target-voltage mode and get the exact resistor values plus the nearest standard E-series resistors.

What do you want to solve for?
Schematic diagram Vout Vin
V
R1
R2
Results
Output voltage
R1
R2
Divider current
Power (R1+R2)

A resistor divider is for sensing and reference levels, not for powering a load. Any current drawn from Vout pulls the voltage down — add a buffer or regulator if the load matters.

Don't pick resistors by hand

A calculator is great for a sanity check — but you still have to translate the numbers into real parts, drop two resistors on a schematic, wire the divider, and label the net. In Flux, you just ask. Flux Copilot picks the E-series resistor pair, places the divider, and wires it into your rail — live on the canvas.

  • Describe the rail, get real E-series parts — not just raw numbers
  • Copilot places and wires the divider for you
  • Swap the target voltage and it re-picks the resistors instantly
Try Flux for free

In Flux

Design a 5 V to 3.3 V voltage divider and place it on my schematic
Flux Copilot

Done! For a 5 V → 3.3 V divider I went with standard E24 resistors:

  • R1 (top): 1.0 kΩ
  • R2 (bottom): 2.0 kΩ

That gives an output of 3.33 V with a divider current of about 1.67 mA.

I've placed both resistors and wired the divider onto your schematic. Want me to try a different ratio or tolerance?

How the voltage divider is calculated

The divider ratio, currents and power are all computed client-side as you type.

01

Divider ratio

The output is Vin scaled by the ratio of the bottom resistor R2 to the total resistance R1 + R2.

02

Solve for a resistor

Fix R1 and a target Vout, and the exact R2 falls out. The calculator then snaps to the nearest E-series value.

03

Current & power

Larger resistors waste less power but are noisier and sag more under load. Check the current and power before you commit.

Voltage divider calculator FAQ