Resistors Series
Calculator

Inputs

Total resistance (Ω)
650

Results

Total resistance (Ω)
650
Circuit current (A)
0.018461
Total power (W)
0.221538

Electrical results

Total resistance (Ω)650
Circuit current (A)0.018461
Total power (W)0.221538

formula-map diagram

Total resistance (Ω)
650
Circuit current (A)
0.018461
Total power (W)
0.221538

Electrical relationship

Formula

R_total = R1 + R2 + R3

= 650

Note

This is a simplified model: it applies the textbook relationship to the numbers you entered and assumes ideal components, steady-state sinusoidal conditions, balanced loads and copper resistivity of 0.0172 Ω·mm²/m at 20 °C. It ignores component tolerances, temperature drift, skin effect, harmonics, inrush, transformer and battery losses, and it is not a substitute for the wiring code that applies where you are. Have any installation sized and verified by a licensed electrician or engineer.

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Frequently asked questions

How do I calculate the total resistance of resistors in series?+

Add the individual resistance values together: R_total = R1 + R2 + R3 + ... The total is always larger than the biggest single resistor in the chain, because current has to fight through every resistance one after another.

Does the order of the resistors change the total?+

No. Addition is commutative, so a 10 ohm followed by a 100 ohm gives the same total as a 100 ohm followed by a 10 ohm. Physical placement along the circuit doesn't affect the math.

Why does adding a resistor in series always increase total resistance?+

Every resistor in a series path adds its own opposition to the same current, so the resistances simply stack. Unlike a parallel combination, there's no alternate path to share the load, so the total can only go up.

What happens to the current in a series circuit?+

The same current flows through every resistor in a series chain, since there's only one path. Voltage divides across each resistor in proportion to its resistance, but the current (in amps) stays identical at every point.

Can I mix resistors with very different values in series?+

Yes, there's no restriction. Just be aware that the smaller resistors will drop very little voltage compared to the larger ones, so if you're trying to divide voltage evenly, mismatched values won't do that.