Resistor Calculator
Series · Parallel · Voltage Divider
Series
Parallel
Voltage Divider
Resistors in series
R1
——
R2
——
Rn
+ Add resistor
Total resistance (R₁ + R₂ + … + Rₙ)
—
Resistors in parallel
R1
∥
R2
∥
Rn
+ Add resistor
Total resistance (1 / (1/R₁ + 1/R₂ + … + 1/Rₙ))
—
Voltage divider
Vin
R1
Vout
R2
GND
Vin (input voltage)
R1 (top resistor)
Ω
kΩ
MΩ
R2 (bottom resistor)
Ω
kΩ
MΩ
Vout
—
Ratio (Vout / Vin)
—
Current draw (Vin ÷ R total)
—
Power dissipated
—
Find R1 or R2
Vin
R1
Vout
R2
GND
Vin
Vout
Know R2, find R1
Know R1, find R2
Known R2
Ω
kΩ
MΩ
R1
—
Ratio (Vout / Vin)
—
Current draw (Vin ÷ R total)
—
Power dissipated
—