Voltage Divider Calculator
Calculate an unloaded two-resistor voltage divider output.
Your inputs
Calculation results
Formula & assumptions
Output = input × bottom resistance/(top+bottom); connected loads change this result.
Values use the specified units. Calculations use floating-point arithmetic. Check input measurements and formula assumptions before applying the result.
Compare your scenarios
Save up to five results to compare changes side by side. Scenarios stay in this tab until you clear or reload it.
Using Voltage Divider Calculator
Calculate an unloaded two-resistor voltage divider output.
- Enter input voltage, top resistor, bottom resistor using the units printed under each field.
- Choose Calculate, or enable live updates. Review the result labels and formula assumptions.
- Save scenarios to compare up to five variations, then copy the report or download JSON or CSV.
Example
Input voltage: 12 volts Top resistor: 10000 ohms Bottom resistor: 5000 ohms Output voltage · volts: 4 Divider current · milliamps: 0.8 Total resistor power · watts: 0.0096
Questions & answers
What does Voltage Divider Calculator calculate?
Calculate an unloaded two-resistor voltage divider output.
Which units should I enter?
Input voltage uses volts. Top resistor uses ohms. Bottom resistor uses ohms. Convert values to these units before calculating.
Which formula does it use?
Output = input × bottom resistance/(top+bottom); connected loads change this result.
What does the included example show?
Input voltage: 12 volts; Top resistor: 10000 ohms; Bottom resistor: 5000 ohms. Result: Output voltage · volts = 4; Divider current · milliamps = 0.8; Total resistor power · watts = 0.0096.
Can I compare different settings?
Yes. Save a scenario, change the inputs and save another result. Up to five scenarios are compared in this tab; they disappear when you reload or leave.
Can I export the calculation?
Copy the JSON report or download JSON and CSV with inputs, result labels and numeric values. Processing uses local JavaScript; no calculation request is sent to our server. Displayed values use up to 10 significant digits; exports retain JavaScript numeric precision.
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