Parallel Resistor Calculator
Total resistance in parallel and series.
Enter your values
Enter the resistances (ohms) you are working with.
Enter the applied voltage in V.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Parallel resistance
- 59.9768 Ω
- Series resistance
- 790 Ω
- Current (parallel)
- 0.20008 A
- Power dissipated
- 2.4009 W
- Resistors entered
- 3
Quick answer
Parallel resistance is the reciprocal of the sum of reciprocals, and is always lower than the smallest resistor.
1/Rt = 1/R₁ + 1/R₂ + …
At a glance
| What it does | Total resistance in parallel and series. |
|---|---|
| Category | Science |
| Inputs needed | Resistances (ohms), Applied voltage |
| Main output | Parallel resistance |
| Formula | 1/Rt = 1/R₁ + 1/R₂ + … |
| Cost | Free — no sign-up, no download |
How to use the Parallel Resistor Calculator
- 1Enter each resistance in ohms, comma separated.
- 2Add the supply voltage for current and power.
- 3Compare parallel and series totals.
Inputs explained
- Resistances (ohms)
- Enter the resistances (ohms) you are working with.
- Applied voltage(V)
- Enter the applied voltage in V.
Worked example
Using the values the calculator loads with:
Inputs
- Resistances (ohms)100, 220, 470
- Applied voltage12 V
Results
- Parallel resistance59.9768 Ω
- Series resistance790 Ω
- Current (parallel)0.20008 A
- Power dissipated2.4009 W
- Resistors entered3
Frequently asked questions
Why is parallel resistance lower?
Extra paths give current more ways to flow, reducing overall opposition.
What about two equal resistors?
Parallel resistance is exactly half of one of them.
What do I need to enter into the Parallel Resistor Calculator?
Just 2 values: resistances (ohms), applied voltage. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the Parallel Resistor Calculator work out the answer?
Parallel resistance is the reciprocal of the sum of reciprocals, and is always lower than the smallest resistor. It applies the formula 1/Rt = 1/R₁ + 1/R₂ + … and shows the working so you can check each step by hand.
Is the Parallel Resistor Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.