Add resistors in series or parallel configuration and get total resistance with automatic unit formatting.
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Quick answers to common questions
For resistors in series, simply add all values: R_total = R1 + R2 + R3 + ... Series resistance is always greater than the largest individual resistor. Example: 100Ω + 220Ω + 330Ω in series = 650Ω total.
Use the reciprocal formula: 1/R_total = 1/R1 + 1/R2 + 1/R3 + ... Parallel resistance is always LESS than the smallest individual resistor. For just two resistors, a shortcut formula works: R_total = (R1×R2)/(R1+R2). Example: 100Ω and 200Ω in parallel = (100×200)/(100+200) = 66.7Ω.
Parallel resistors provide multiple paths for current to flow, effectively increasing the total cross-sectional area for current — similar to adding more lanes to a highway. More paths means less overall opposition to current flow, hence lower total resistance.
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