Supply Vin and two series resistors R1 (top) and R2 (bottom to ground)—output at the junction.
With resistors R₁ and R₂ in series to ground, Vout = Vin × R₂ ÷ (R₁ + R₂). Both resistances must be positive; the page also shows the tap ratio R₂ ÷ (R₁ + R₂). Loading and tolerance are not modeled.
This calculator uses plain decimal numbers. If a result looks wrong, check whether you used a comma instead of a dot (or vice versa) where the field expects one.