Voltage Divider & Tolerance Calculator
Enter the known values and run the calculation.
Overview
Size resistor-divider networks and inspect tolerance-driven output spread in one place.
This tool calculates the nominal output voltage of a two-resistor divider and then estimates the worst-case high and low output caused by resistor tolerance.
It is useful when a divider is feeding an ADC input, bias node, reference input, or any other circuit point where the output range matters as much as the nominal target.
The math and how it's used
The nominal divider equation is Vout = Vin * R2 / (R1 + R2).
Worst-case output is estimated by pushing R1 and R2 to opposite ends of the tolerance band. Low output uses R1 high and R2 low. High output uses R1 low and R2 high.
Use this when a clean divider ratio on paper turns into a tolerance stack question in real hardware.
It is a first-pass check for resistor-divided nodes. Bias current, source impedance, load impedance, tempco, and resistor tracking still matter if the design margin is tight.
When it matters
Tolerance spread matters when the divider feeds logic thresholds, precision references, sensor scaling inputs, or protection circuits with narrow limits.
If loading from the next stage is not negligible, treat this as a first-pass estimate and include the input impedance of the receiving circuit in the final design.