Voltage Divider Calculator


Formulas:
  • \( V_{\text{out}} = \frac{R_2}{R_1 + R_2} \times V_{\text{in}} \)
  • \( V_{\text{in}} = V_{\text{out}} \times \frac{R_1 + R_2}{R_2} \)
  • \( R_1 = R_2 \times \left( \frac{V_{\text{in}}}{V_{\text{out}}} - 1 \right) \)
  • \( R_2 = R_1 \times \frac{V_{\text{out}}}{V_{\text{in}} - V_{\text{out}}} \)
Where:
  • Vin is the source voltage, measured in volts (V).
  • R1 is the resistance of the 1st resistor, measured in Ohms (Ω).
  • R2 is the resistance of the 2nd resistor, measured in Ohms (Ω).
  • Vout is the output voltage, measured in volts (V).
Voltage Divider Diagram
Result:
Blank
Enter values for any three of the parameters and
click "Calculate" to find the remaining parameter.

Resistor Values Table


Ω Ω Ω kΩ kΩ kΩ MΩ
1.0 Ω 10 Ω 100 Ω 1.0 kΩ 10 kΩ 100 kΩ 1.0 MΩ
1.1 Ω 11 Ω 110 Ω 1.1 kΩ 11 kΩ 110 kΩ 1.1 MΩ
1.2 Ω 12 Ω 120 Ω 1.2 kΩ 12 kΩ 120 kΩ 1.2 MΩ
1.3 Ω 13 Ω 130 Ω 1.3 kΩ 13 kΩ 130 kΩ 1.3 MΩ
1.5 Ω 15 Ω 150 Ω 1.5 kΩ 15 kΩ 150 kΩ 1.5 MΩ
1.6 Ω 16 Ω 160 Ω 1.6 kΩ 16 kΩ 160 kΩ 1.6 MΩ
1.8 Ω 18 Ω 180 Ω 1.8 kΩ 18 kΩ 180 kΩ 1.8 MΩ
2.0 Ω 20 Ω 200 Ω 2.0 kΩ 20 kΩ 200 kΩ 2.0 MΩ
2.2 Ω 22 Ω 220 Ω 2.2 kΩ 22 kΩ 220 kΩ 2.2 MΩ
2.4 Ω 24 Ω 240 Ω 2.4 kΩ 24 kΩ 240 kΩ 2.4 MΩ
2.7 Ω 27 Ω 270 Ω 2.7 kΩ 27 kΩ 270 kΩ 2.7 MΩ
3.0 Ω 30 Ω 300 Ω 3.0 kΩ 30 kΩ 300 kΩ 3.0 MΩ
3.3 Ω 33 Ω 330 Ω 3.3 kΩ 33 kΩ 330 kΩ 3.3 MΩ
3.6 Ω 36 Ω 360 Ω 3.6 kΩ 36 kΩ 360 kΩ 3.6 MΩ
3.9 Ω 39 Ω 390 Ω 3.9 kΩ 39 kΩ 390 kΩ 3.9 MΩ
4.3 Ω 43 Ω 430 Ω 4.3 kΩ 43 kΩ 430 kΩ 4.3 MΩ
4.7 Ω 47 Ω 470 Ω 4.7 kΩ 47 kΩ 470 kΩ 4.7 MΩ
5.1 Ω 51 Ω 510 Ω 5.1 kΩ 51 kΩ 510 kΩ 5.1 MΩ
5.6 Ω 56 Ω 560 Ω 5.6 kΩ 56 kΩ 560 kΩ 5.6 MΩ
6.2 Ω 62 Ω 620 Ω 6.2 kΩ 62 kΩ 620 kΩ 6.2 MΩ
6.8 Ω 68 Ω 680 Ω 6.8 kΩ 68 kΩ 680 kΩ 6.8 MΩ
7.5 Ω 75 Ω 750 Ω 7.5 kΩ 75 kΩ 750 kΩ 7.5 MΩ
8.2 Ω 82 Ω 820 Ω 8.2 kΩ 82 kΩ 820 kΩ 8.2 MΩ
9.1 Ω 91 Ω 910 Ω 9.1 kΩ 91 kΩ 910 kΩ 9.1 MΩ

Resistor Colour Chart


resistor-colour-chart/

Ohms Law Wheel


Ohm's law (named after the German physicist Georg Ohm) defines the relationship between Voltage, Current, and Resistance.

\( V = I \times R \)

Joule's law states that:

\( P = V \times I \)

The combination of Ohm's law and Joule's law gives us 12 formulas where 2 of the 4 variables are known. The wheel below is a handy tool and memory jogger. To use it, simply choose the quadrant corresponding to the variable you want to calculate, then select the segment corresponding to the variables that you know the values of.

ohms-law-wheel/