Resistors in Parallel Calculator

Resistors in Parallel Calculator. When resistors are connected in parallel in a circuit, their combined resistance drops below the lowest individual value — and the Resistors in Parallel Calculator works out that combined resistance for you. Select the number of resistors (2–10), then enter each resistor value in Ω, kΩ, or MΩ to get the equivalent resistance, plus total current draw and total power dissipation at 5V. Also try the calculate Resistor Color Code (5-Band).

Results

Equivalent Resistance

Total Current (at 5V)

Total Power (at 5V)

Results Table

How do you calculate two resistors in parallel?

For two resistors in parallel, use the formula: 1/R_total = 1/R1 + 1/R2, or the simplified formula: R_total = (R1 × R2) / (R1 + R2). The equivalent resistance is always less than the smallest individual resistor.

Why does resistance decrease in parallel circuits?

In parallel circuits, adding more resistors creates additional current paths. More paths for current to flow means less total resistance, which is why the equivalent resistance decreases as you add more resistors in parallel.

Is the voltage the same in a parallel circuit?

Yes, in a parallel circuit, the voltage across each resistor is the same and equals the source voltage. This is a key characteristic that distinguishes parallel circuits from series circuits.

What is the parallel resistance formula for multiple resistors?

For multiple resistors in parallel, the formula is: 1/R_total = 1/R1 + 1/R2 + 1/R3 + ... + 1/Rn. This means you add the reciprocals of all individual resistances and then take the reciprocal of the sum.

How do you find an unknown resistor in a parallel circuit?

If you know the total equivalent resistance and all other resistor values, rearrange the parallel formula to solve for the unknown resistor: 1/R_unknown = 1/R_total - 1/R1 - 1/R2 - ... (for all known resistors).

Can I mix different units like ohms and kiloohms?

Yes, this calculator automatically handles unit conversion. You can enter resistors in ohms (Ω), kiloohms (kΩ), or megaohms (MΩ), and the calculator will convert everything to the appropriate units for calculation.

What happens when one resistor is much smaller than others in parallel?

When one resistor is much smaller than the others in a parallel circuit, it dominates the equivalent resistance. The total resistance will be close to the value of the smallest resistor, as current prefers the path of least resistance.