Voltage divider calculator
A resistive divider produces an output that is a fixed fraction of its input. It only holds while the load draws negligible current compared with the divider itself, so keep the resistors small relative to whatever they feed.
Results
- Output voltage
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- Divider current
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- Divider ratio
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Results update as you type.
Formula
Vout = Vin × R2 / (R1 + R2)
I = Vin / (R1 + R2)
How it works
R1 sits between the input and the output node; R2 sits between the output node and ground. The output is pulled toward ground by R2 and toward Vin by R1, landing at the ratio above.
The current shown is the quiescent current wasted in the divider itself. Smaller resistors give a stiffer output but burn more current — a design trade-off, not a bug.
Build one on the canvas to watch the midpoint node settle, then load it and see the output sag as the load resistance drops.