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Physics

Voltage Divider Calculator

Vout = Vin × R2 / (R1 + R2). Free online Voltage Divider Calculator. Calculate voltage divider online — fast, accurate, mobile-friendly, no signup needed.

Vout (V)
8

Derivation

  1. ├── 01GivenVin = 12, R1 = 1000, R2 = 2000
  2. ├── 02Formulat × n / (a+n)
  3. └── 03Compute Vout (V)8
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§01What is

Understanding the Voltage Divider Calculator

The Voltage Divider Calculator computes Vout (V) from 3 inputs: vin (v), r1 (ω), r2 (ω). Vout = Vin × R2 / (R1 + R2).

Physics is the toolkit for turning a real-world observation into a prediction. Whether it’s a falling object, a moving car, or a stressed beam, the equations here are the same ones every engineer relies on. The Voltage Divider Calculator sits in that toolkit — it vout = Vin × R2 / (R1 + R2). Enter your numbers above and the result updates instantly; every step of the math is shown in the Derivation panel so you can see exactly how the answer was reached.

§02The Formula

How it’s calculated

t × n / (a+n)

Where

Vin
Vin (V)
R1
R1 (Ω)
R2
R2 (Ω)
§03Practical Example

Step-by-step walkthrough

Scenario

Apply the formula to a realistic set of inputs: Vin (V) = 12, R1 (Ω) = 1000, R2 (Ω) = 2000.

  1. 01Start by noting the input — Vin (V): 12.
  2. 02Start by noting the input — R1 (Ω): 1000.
  3. 03Start by noting the input — R2 (Ω): 2000.
  4. 04Substitute these values into the formula: t × n / (a+n)
  5. 05Compute Vout (V): the calculator returns 8.
  6. 06Cross-check the answer by opening the Derivation panel above — every line of math is shown so you can follow the computation end-to-end.
§04Variants

Common Voltage Divider Problems

The formula gets rearranged depending on which variable you need. Here are the patterns you’ll run into in the real world — find the one that matches your problem and follow the worked steps.

01 · PATTERN

Vin (V) halved

Vin = 6 (from 12)

Keep every other input at its default and halve the vin (v). See how vout (v) responds.

  1. 01New Vin (V): 6
  2. 02Baseline Vout (V): 8
  3. 03New Vout (V): 4
  4. 04Vout (V) decreases by 50% → use this sensitivity to plan for real-world variation.
02 · PATTERN

Vin (V) doubled

Vin = 24 (from 12)

Keep every other input at its default and double the vin (v). See how vout (v) responds.

  1. 01New Vin (V): 24
  2. 02Baseline Vout (V): 8
  3. 03New Vout (V): 16
  4. 04Vout (V) increases by 100% → use this sensitivity to plan for real-world variation.
03 · PATTERN

R1 (Ω) halved

R1 = 500 (from 1000)

Keep every other input at its default and halve the r1 (ω). See how vout (v) responds.

  1. 01New R1 (Ω): 500
  2. 02Baseline Vout (V): 8
  3. 03New Vout (V): 9.6
  4. 04Vout (V) increases by 20% → use this sensitivity to plan for real-world variation.
04 · PATTERN

R1 (Ω) doubled

R1 = 2000 (from 1000)

Keep every other input at its default and double the r1 (ω). See how vout (v) responds.

  1. 01New R1 (Ω): 2000
  2. 02Baseline Vout (V): 8
  3. 03New Vout (V): 6
  4. 04Vout (V) decreases by 25% → use this sensitivity to plan for real-world variation.
§05FAQ

Frequently asked questions

Yes. The calculator implements the standard formula as documented and returns exact floating-point results. No approximations are used unless noted in the formula.
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