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Voltage Divider Calculator

Calculate output voltage and series current for two resistors.

01 / INPUTS

V
Ω
Ω

02 / RESULT

Output voltage (Vout)
8 V
Current
0.004 A

Calculation trace

  1. 12 V × 2,000 Ω ÷ (1,000 Ω + 2,000 Ω) = 8 V
    8 V
    Output voltage
  2. 12 V ÷ (1,000 Ω + 2,000 Ω) = 0.004 A
    0.004 A
    Current
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How it works

A two-resistor divider outputs Vout = Vin · R2 / (R1 + R2). The series current is I = Vin / (R1 + R2). Both follow directly from Ohm’s law.

Assumptions & limits

  • Assumes an ideal, unloaded divider — a load across R2 changes the output.
  • Resistors are treated as ideal and ohmic.
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FAQ

Why is my real output lower than calculated?
Any load connected across R2 draws current and pulls the output down. Size the divider so its current is much larger than the load current.
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