Calculators / Quick tool
Voltage Divider Calculator
Calculate unloaded divider output, current and resistor power from explicit values.
How to useHow to use Voltage Divider Calculator ⌄
Calculate unloaded divider output, current and resistor power from explicit values.
- 1
Paste content, enter parameters or choose the files you need in “Input voltage, R1 and R2”.
- 2
Choose “Calculate divider” for the job. Processing runs in this browser.
- 3
Review the result under “Divider result”, then copy or download it after checking the output.
Result guide
What Voltage Divider Calculator calculates
For an ideal two-resistor divider, Vout is measured across R2: Vout = Vin × R2/(R1 + R2). The calculator also reports total resistance, divider current, and each resistor's power.
Frequently asked questions
What voltage-divider formula is used?
For R1 above the output node and R2 to ground, the ideal unloaded output is Vout = Vin × R2/(R1 + R2).
How does a connected load change Vout?
A load in parallel with R2 reduces the effective lower resistance, so the real output is usually lower than this unloaded result. Model the parallel load separately for design work.
What units should I use for R1 and R2?
Enter both resistors in the same unit. The sample uses ohms, so current is returned in amperes and power in watts.
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