Voltage divider calculator
Find output voltage or the lower resistor, including an optional resistive load. Drag the graph handles to change inputs and explore the result.
Your inputs
Example values are editable. Use your measurements and product specifications. Results update as you edit.
Calculations run in your browser. Inputs are not saved or sent to analytics.
How it works
- Vout = × / ( + )
- Rlower = 1 / (1/ + 1/); Vout = × Rlower / ( + Rlower)
- Rlower = × / ( − ); R2loaded = 1 / (1/Rlower − 1/)
- P = I² × R
Input and formula key
Your result
Complete the inputs to see your result.
Assumptions and limitations
Ideal DC resistors with R1 above R2. A load is parallel to R2. Values are nominal: component tolerances, temperature, transient response and preferred stock values are excluded. Example: 12 V, 10 kΩ and 2 kΩ without load produce 2 V.
Sources
- Texas Instruments — voltage divider calculator Sources reviewed: 2026-10-10
- OpenStax — resistors in series and parallel Sources reviewed: 2026-10-10
