Four 100 Ω Resistors in Parallel
Four 100 Ω resistors in parallel yield exactly 25 Ω equivalent resistance.
How to use this tool
- Enter r1, r2, r3 (optional) and r4 (optional) in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your equivalent resistance and the full breakdown beneath it.
Four identical 100 Ω resistors in parallel give exactly 25 Ω — a useful technique for achieving non-standard low resistance values with higher power handling.
Frequently asked questions
- Why is the result always lower than the smallest resistor?
- Adding parallel paths gives current more routes to flow, reducing total opposition. Each additional resistor adds conductance (1/R) to the total.
- What is the quick formula for two resistors in parallel?
- Rp = (R1 × R2) / (R1 + R2) — the product over sum. Works only for two resistors.