Calculate output voltage (Vout) across R2 in a simple two-resistor voltage divider circuit.
Output Voltage
0.00
Vout
Voltage Drop (R1)
0.00
V
Current (I)
0.00
mA
Formula: Vout = Vin × (R2 / (R1 + R2))
Our professional Voltage Divider Calculator helps electronics engineers, hobbyists, students, and circuit designers quickly calculate output voltages and resistor values for voltage divider circuits. Whether you're designing sensor interfaces, creating reference voltages, building analog circuits, or learning electronics fundamentals, this tool provides accurate calculations following Ohm's Law and voltage divider formulas.
Calculate output voltage from resistor values, determine resistor values for desired output, analyze load effects on voltage dividers, check power dissipation in resistors, and design stable reference circuits with our specialized electronics engineering calculator.
Calculates both unloaded and loaded voltage dividers. For loaded dividers: Vout = Vin × (R2∥RL) / (R1 + R2∥RL). Essential for real-world circuit design where loads affect voltage.
Calculate forward (Vout from resistors) or reverse (resistors from Vout). Solves for R1 and R2 given Vin, Vout, and either R1 or R2 value using formulas: R2 = R1 × (Vout/(Vin-Vout)).
Calculates power dissipation: P = I²R or V²/R. Recommends resistor wattage ratings (1/4W, 1/2W, 1W). Prevents resistor overheating and ensures circuit reliability.
Calculates Thevenin equivalent: Vth = Vout (unloaded), Rth = R1∥R2. Shows output impedance (Zout) critical for driving capacitive loads or high-frequency applications.
Used by electronics engineers, hobbyists, students, and embedded systems designers worldwide. Design accurate voltage references and interface circuits with confidence!
The basic voltage divider formula is: Vout = Vin × (R2 / (R1 + R2)). For a 12V input with R1=10kΩ and R2=10kΩ: Vout = 12 × (10,000 / (10,000 + 10,000)) = 12 × 0.5 = 6V.
Load resistance (RL) parallels R2, reducing effective resistance. Example: With R1=10k, R2=10k, Vin=12V: Unloaded Vout=6V. With RL=10k: Effective R2 = 5k, Vout = 12 × (5k/(10k+5k)) = 4V. Load reduces output by 33%.
Choose resistors based on: 1) Current (I = Vin/(R1+R2)), 2) Load impedance (RL should be ≥10×R2 for <5% error), 3) Power rating (P = I²R). Typical values: 1kΩ-100kΩ for low-power circuits.
Use an op-amp voltage follower when: Load impedance is low (<10×R2), High accuracy needed (<1% error), or Driving capacitive loads. The op-amp provides near-zero output impedance while maintaining Vout.
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