Voltage Divider Calculator

May 14, 2026 Voltage Divider Calculator Interactive Calculator

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Compute divider output voltage or solve for R2 from a target output voltage.

Input Voltage

R2 (or leave blank and use target output)

Target Output Voltage (optional)

Example Inputs: Vin = 12V, R1 = 10k, R2 = 10k

Example Output: Vout = 6V

Live Result: Enter values and click Calculate.

Vout = Vin * R2 / (R1 + R2), and R2 = (Vout * R1) / (Vin - Vout)

Use the example inputs and outputs above to walk through the calculation step-by-step.

Can I solve for output voltage?
Yes. Enter Vin, R1, and R2 to get Vout.

Can I solve for resistor value from a target Vout?
Yes. Provide Vin, R1, and target Vout, and the calculator computes required R2.

When should I avoid a divider?
A passive divider is unsuitable for heavy loads because load current changes the output voltage.

Recommended products for this calculator workflow.

Part #: RSMF2JB43K0

Category: Fixed Resistors

Available Qty: 0

View Product

Use resistor ratio to scale a source voltage to a lower reference output.

Equal resistors split the source in half, so 12V becomes 6V.

Results are estimates. Verify calculations against component datasheets before safety-critical use.

Formula Notes