How to Calculate Current in a Parallel Circuit (Made Simple!) - OneSDR

🔌 If you’ve ever looked inside an electronic device or learned about electricity in school, you’ve probably heard of parallel circuits. But how do you calculate current in one?

Don’t worry—this guide will walk you through it step by step. No confusing jargon, just simple explanations!

Table of Contents

⚡ What Is a Parallel Circuit?

In a parallel circuit, electrical components are connected side by side, and each path has its own direct connection to the power source.

Think of it like:

Multiple lanes on a highway: cars (current) can travel on different paths at the same time.
Each bulb or resistor has its own road from the battery.

📌 Key Fact: In a parallel circuit, the voltage across each branch is the same.

🔍 What Is Electric Current?

Current (I) is the flow of electric charge, measured in amperes (A).

In a parallel circuit:

The total current (Itotal) from the power source is split between the branches.
Each branch has its own current, depending on the resistance.

🧮 Step-by-Step: How to Calculate Current in a Parallel Circuit

Let’s say we have a battery and three resistors in parallel:

Voltage (V) = 12 volts
Resistor 1 (R₁) = 6 ohms
Resistor 2 (R₂) = 4 ohms
Resistor 3 (R₃) = 12 ohms

Step 1: Use Ohm’s Law for Each Branch

Ohm’s Law is:

I = V / R

Calculate current for each branch:

I₁ = 12 / 6 = 2 A
I₂ = 12 / 4 = 3 A
I₃ = 12 / 12 = 1 A

Step 2: Add All the Currents Together

Itotal = I₁ + I₂ + I₃  
Itotal = 2 + 3 + 1 = 6 A

🎉 The total current from the battery is 6 amperes.

⚙️ Parallel Current Calculator

Enter

any number of resistor values separated by commas
voltage across the resistors

The tool will provide the total current across the resistors

📚 Total Current with Parallel Resistance Formula

R_total = (1/R₁ + 1/R₂ + 1/R₃+…. + 1/R_n)^-1

I_total = V/R_total

✏️ Example Calculation

Consider four resistors in parallel: 1 Ω, 2 Ω, 3 Ω, 4 Ω and 5 Ω. The total effective resistance is 0.44 Ω.

For a voltage value of 5V, the total current is 5/0.44 = 11.42 A

📌 Quick Recap

Branch	Resistance (R)	Voltage (V)	Current (I = V/R)
1	6 ohms	12 V	2 A
2	4 ohms	12 V	3 A
3	12 ohms	12 V	1 A
			Total: 6 A

✅ Tips to Remember

In a parallel circuit, voltage is the same across all branches
Current splits across the branches
Use Ohm’s Law for each branch separately
Add all the individual currents to get the total current