Resistance Calculator
Calculate electrical resistance using Ohm's law (R = V / I). Also computes series and parallel resistance combinations.
Enter values to calculate resistance.
Resistance Formula
R = V / I (Ohm's Law)
Series: Rtotal = R₁ + R₂ + R₃ + ...
Parallel: 1/Rtotal = 1/R₁ + 1/R₂ + 1/R₃ + ...
Series: Rtotal = R₁ + R₂ + R₃ + ...
Parallel: 1/Rtotal = 1/R₁ + 1/R₂ + 1/R₃ + ...
Example: A circuit with 9 V and 0.3 A.
R = 9 / 0.3 = 30 Ω
R = 9 / 0.3 = 30 Ω
Series vs Parallel Resistance
- Series: Total resistance increases. Current is the same through all resistors.
- Parallel: Total resistance decreases. Voltage is the same across all resistors.
FAQ
What factors affect resistance?
Resistance depends on material (resistivity), length (longer = more resistance), cross-sectional area (larger = less resistance), and temperature.
What is a resistor?
A resistor is an electronic component that provides a specific amount of resistance in a circuit. It limits current flow and divides voltage.
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Last updated: 2026-08-08