Voltage Divider Calculator
Calculate the output voltage and current of a two-resistor voltage divider. Formula, worked example and a table of typical values.
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Estimate only. Not engineering or safety advice. Check the result against the applicable standard and the equipment data, and have a competent engineer review it before it is relied on. Terms of use.
Open in the calculator with these values
Formula
Worked example
| Input | Value |
|---|---|
| Input voltage | 12 V |
| Upper resistor R1 | 10 kΩ |
| Lower resistor R2 | 10 kΩ |
- Vout = 12 × 10,000 / 20,000 = 6 V
- I = 12 / 20,000 = 0.6 mA
Typical values
| Lower resistor R2 (kΩ) | Output voltage (V) |
|---|---|
| 1 | 1.091 |
| 2.2 | 2.164 |
| 4.7 | 3.837 |
| 10 | 6 |
| 22 | 8.25 |
| 47 | 9.895 |
Other inputs are the same as in the worked example above.
Assumptions
- Unloaded output: no current drawn from the midpoint
- Resistors are ideal
A load on the output in parallel with R2 lowers Vout. Keep the load at least ten times R2 for a stable output.
Frequently asked questions
How is Voltage Divider calculated?
Vout = Vin × R2 / (R1 + R2); I = Vin / (R1 + R2). Worked example: Input voltage 12 V, upper resistor R1 10 kΩ, lower resistor R2 10 kΩ gives 6 V.
What do I need to enter?
Enter input voltage, upper resistor R1 and lower resistor R2. Change the unit of a value with its selector and the result stays the same.
What happens when I connect a load to the output?
A load in parallel with R2 lowers the output voltage. Keep the load resistance at least ten times R2 for a stable output.
How accurate are the results?
Every figure comes from the same tested engine as the Elecmetric calculators and is meant for estimating. Check design values against the standard and the equipment data you work to.
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All 78 conversionsVoltage Divider in Elecmetric