FREE · CONSTRUCTION & TRADE CALCULATORS
Voltage Divider Calculator.
Calculate the output of a resistor voltage divider, or the resistor needed for a target voltage, including the effect of a load and standard values.
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How to use Voltage Divider Calculator
Choose what to solve for, enter the input voltage and resistors in kΩ, and optionally a load. When solving for a resistor, pick the E-series to round to.
How it works
Vout = Vin × R2 ÷ (R1 + R2), with R2 replaced by R2 ∥ R_load when a load is present. Currents and power in each resistor are shown.
Example
12 V with R1 = 10 kΩ and R2 = 4.7 kΩ gives 3.8367 V; a 10 kΩ load pulls it down to 2.9072 V.
Questions about Voltage Divider Calculator
Is Voltage Divider Calculator free, and do I need an account?
Yes. This tool is free to use in your browser without an account. Processing takes place on your device.
What are the limits and what should I check?
Ideal resistors and a resistive load. Not a voltage regulator. Everything is calculated in your browser; nothing you type is uploaded. Review the result before using it in your work.
Is my input sent to a server?
Your input is processed in your browser and is not uploaded by this tool. Files and pasted text are cleared when the page is refreshed. Normal website requests are still required to load the page and its libraries. Read the privacy explanation.