Voltage divider
Choose a resistor ratio, account for loading and explore component tolerance.
Development preview. Check the assumptions below before relying on a result. Calculations run in your browser.
How it calculates
A resistive divider follows Vout = Vin × (R2 ∥ RL) / [R1 + (R2 ∥ RL)]. Remove RL for the unloaded case. The source is ideal and the resistors are linear.
Assumptions
- DC resistive divider with an ideal voltage source. R1 connects the input to the output; R2 and the optional load connect the output to ground.
- Output resistance is the unloaded Thevenin resistance R1 ∥ R2, with an ideal input source.
- Input resistor values are specified at the reference temperature. Schematic values and dissipation use their effective operating values.
- Loading and component tolerance are included. Source resistance, dynamic behaviour and resistor self-heating are not modelled.
- Choose component ratings using actual datasheets and operating conditions.
Worked example
These are the calculator's default inputs. Change any input above to recalculate.
Inputs
- Input voltage
- 12 V
- Top resistor R1
- 10000 Ω
- Bottom resistor R2
- 4700 Ω
Results
- Output voltage
- 3.83673 V
- Divider current
- 0.000816327 A
- Output resistance
- 3197.28 Ω
- R1 dissipation
- 0.00666389 W
- R2 dissipation
- 0.00313203 W