Find your output voltage in seconds. Enter Vin, R1 and R2 to get the divider output, current and power — or flip to target-voltage mode and get the exact resistor values plus the nearest standard E-series resistors. It is also a resistor divider calculator: the two names describe the same two-resistor circuit.
A resistor divider is for sensing and reference levels, not for powering a load. Any current drawn from Vout pulls the voltage down — add a buffer or regulator if the load matters.
A calculator is great for a sanity check — but you still have to translate the numbers into real parts, drop two resistors on a schematic, wire the divider, and label the net. In Flux, you just ask. Flux picks the E-series resistor pair, places the divider, and wires it into your rail — live on the canvas.
Done! For a 5 V → 3.3 V divider I went with standard E24 resistors:
That gives an output of 3.33 V with a divider current of about 1.67 mA.
I've placed both resistors and wired the divider onto your schematic. Want me to try a different ratio or tolerance?
The divider ratio, currents and power are all computed client-side as you type.
The output is Vin scaled by the ratio of the bottom resistor R2 to the total resistance R1 + R2.
Fix R1 and a target Vout, and the exact R2 falls out. The calculator then snaps to the nearest E-series value.
Larger resistors waste less power but are noisier and sag more under load. Check the current and power before you commit.
Engineers call this circuit a resistor divider, a resistive divider or a voltage divider. The names are interchangeable, because the divider is built from two resistors and the output depends only on their ratio. Use the calculator above for either term.
A resistor divider is the right tool for scaling a signal into an ADC, setting a comparator threshold, biasing a transistor, or making a reference level. It is the wrong tool for powering a rail: the output impedance is R1 ∥ R2, so a real load pulls the voltage down. Enter your load resistance in the optional field to see how far the output sags.
