Elysia Tools
Navigation
Math & Numbers
Combine resistors in series, parallel, or an arbitrary +/| expression, with per-resistor voltage and power
Details
Combine a list of resistors into one equivalent resistance.
Modes:
Value suffixes: k/K, M, m, u/µ. With an optional voltage, total current and per-resistor power are reported.
Execution
Fill in the form, run the tool, and review the result in one place.
Samples
Related
Ready for a run
Tool usage guide
The Resistor Series / Parallel Calculator helps you quickly determine the equivalent resistance of any resistor network. It supports simple series and parallel combinations, custom mathematical expressions using series (+) and parallel (|) operators, and calculates total current and individual resistor power dissipation when an optional voltage is provided.
Background
A hobbyist is building an LED driver circuit and needs a 500 ohm resistor, but only has 1k ohm resistors available.
Problem
Determine the equivalent resistance of two 1k ohm resistors connected in parallel.
How to use
Select 'Parallel' mode and enter '1000' and '1000' on separate lines.
mode: parallel
rawValues: 1000
1000Outcome
The calculator outputs an equivalent resistance of 500 Ω.
Background
A student is analyzing a voltage divider network consisting of two parallel 10k resistors in series with a 470 ohm resistor, powered by a 12V source.
Problem
Find the equivalent resistance and check the power distribution across the network.
How to use
Select 'Expression' mode, enter '(10k|10k)+470' in the values field, and input '12' in the Applied Voltage field.
Use '+' for series connections and '|' for parallel connections, along with parentheses to define the order of operations.
You can use standard suffixes like k or K (kiloohms), M (megaohms), m (milliohms), and u or µ (microohms).
Enter a value in the Applied Voltage field, and the calculator will automatically compute the current and power for each resistor.
Yes, the calculator automatically normalizes values like 10k, 470, and 2.2M to ohms before performing the calculation.
The calculator uses the reciprocal formula: 1/R_eq = 1/R1 + 1/R2 + ... + 1/Rn.
mode: expr
rawValues: (10k|10k)+470
voltage: 12Outcome
The equivalent resistance is calculated as 5470 Ω, and the tool outputs the total current and power dissipation for each resistor.