Resistor Series and Parallel Calculator – Online Ohm Resistance Calculator

Also try Capacitor Series and Parallel Calculator

Theory of Resistors in Series and Parallel

Resistors are basic electronic components that resist the flow of current. When you connect them in series or parallel, their total resistance changes.

🔗 1. Resistors in Series

📌 Concept:

• In series, resistors are connected end-to-end.
• Current remains same through all resistors.
• Voltage gets divided across them.

🧮 Formula:

If you have resistors $\dots$ then:

$$\dots .$$

Just add all the resistance values — as simple as adding apples.

🔍 Example:

If you have:

• R1=10Ω
• R2=20Ω
• R3=30Ω

Then:

R_total=10+20+30=60Ω

🧲 2. Resistors in Parallel

📌 Concept:

• In parallel, resistors are connected side by side.

• Voltage across each resistor is the same.

• Current gets divided between them.

🧮 Formula:

If you have resistors R1,R2,R3..… then:

1/R_total=1/R1+1/R2+1/R3+……

Then take the reciprocal to find R_total.

✨ Shortcut for two resistors:

R_total=R1⋅R2/R1+R2​​

🔍 Example:

If you have:

• R1=10Ω
• R2=20Ω

Then:

1/R_total=1/10+1/20=3/20⇒R_total=20/3≈6.67Ω

🔢 What This Calculator Does

1. Takes multiple resistor inputs (with values and units like Ohm, kΩ, MΩ).
2. Converts everything into Ohms internally.
3. Based on selected mode (series/parallel), applies the correct formula:

• Series: Adds all values.
• Parallel: Uses reciprocal sum.

Converts the result back into:

• Ohms
• Kiloohms (kΩ)
• Megaohms (MΩ)

Displays the result in all units neatly.

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