Voltage Divider Calculator

Calculate output voltage from a resistive voltage divider circuit.

By Konstantin Iakovlev · Updated April 2026 · Source: IETF

V
Ω
Ω

Output Voltage

6.000 V

Current

0.600 mA

Details

Vout6.000 V
Division Ratio0.5000
Total Current0.600 mA
Power (R1)3.600 mW
Power (R2)3.600 mW
FormulaVout = Vin × R2 / (R1 + R2)

Use the Voltage Divider Calculator above to calculate your results. Enter your values and see instant results — all calculations run in your browser.

Disclaimer: This calculator is for informational purposes only and does not constitute tax, financial, or legal advice. Results are estimates based on the information you provide and current rates. Always consult a qualified tax professional or financial advisor for advice specific to your situation.

How It Works

Working out the output of a resistive divider is a routine step when designing sensor interfaces, setting reference voltages, or scaling signals, and it grows more important as demand for precise low-power IoT devices is projected to grow by 15% in 2026. Dividing voltage cleanly is central to keeping power consumption in check and circuits stable as electronic systems get denser.

Output voltage follows Vout = Vin * (R2 / (R1 + R2)), where Vin is the input voltage to the divider, R1 is the resistor tied to Vin, and R2 is the resistor tied to ground, with Vout measured across it. The relationship comes straight out of Ohm's Law and Kirchhoff's Voltage Law, on the assumption of an ideal voltage source and no load drawing from Vout.

A divider is meant for signal scaling or setting a reference, not for supplying meaningful current, so treating it as a power supply leads to trouble. The most frequent oversight is ignoring a load on Vout, which sits in parallel with R2 and pulls the output away from the calculated value. Where real current or tight regulation is needed, a voltage regulator is the right tool rather than a plain divider.

Example: Scaling a Sensor Output for an ADC in 2026

  1. 1 Imagine you have a new environmental sensor, the 'EcoSense 2026', that outputs a maximum of 5V, but your microcontroller's Analog-to-Digital Converter (ADC) can only handle a maximum input of 3.3V. You need to scale down the sensor's 5V output to be compatible with the ADC.
  2. 2 Let's choose R1 = 10kΩ and R2 = 20kΩ. Using the formula: Vout = 5V * (20kΩ / (10kΩ + 20kΩ)) = 5V * (20kΩ / 30kΩ) = 5V * (2/3) ≈ 3.33V.
  3. 3 The calculated output voltage (Vout) would be approximately 3.33V.
  4. 4 This 3.33V output is perfectly within the 3.3V maximum input range of your microcontroller's ADC, allowing you to safely and accurately read the data from your advanced EcoSense 2026 sensor without damaging your microcontroller. The slight excess of 0.03V would typically be handled by the ADC's input protection or simply registered as the maximum 3.3V without harm.

Source: IETF · Last updated: April 2026

Frequently Asked Questions

How does a voltage divider work?
A voltage divider uses two resistors in series to create an output voltage that is a fraction of the input. Output voltage = Vin x R2/(R1+R2). For example, with R1=1kΩ, R2=2kΩ, and 9V input, output is 6V.
When should you use a voltage divider?
Voltage dividers are used for sensor signal conditioning, reference voltage generation, level shifting, and reading analog voltages. They work best with high-impedance loads that draw minimal current.
Why does loading affect voltage divider output?
Connecting a load in parallel with R2 effectively reduces the bottom resistance, lowering the output voltage. For accurate results, the load impedance should be at least 10x greater than R2.

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