Calculate total resistance for up to 10 resistors in series or parallel. Enter supply voltage to find current and power.
Supply Voltage (V) optionalV
About Series & Parallel Resistor Calculator
Series & Parallel Resistor Calculator is a free scientific calculation tool that helps students, researchers, and engineers calculate total resistance for up to 10 resistors in series or parallel. enter supply voltage to find current and power. Instead of looking up formulas and calculating by hand, enter your values and get instant, accurate results with clear explanations of the underlying science.
How to Use
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Enter your known valuesFill in the input fields with the values you have. The tool will calculate the unknowns.
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Select units if applicableChoose the correct units for your calculation to ensure accurate results.
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Review the solutionCheck the calculated result along with any formulas, steps, or diagrams shown.
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Explore different valuesChange inputs to see how different values affect the outcome. Great for building scientific intuition.
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Why Use Series & Parallel Resistor Calculator?
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Verified FormulasSeries & Parallel Resistor Calculator implements standard scientific formulas from physics, chemistry, and mathematics textbooks. Results you can trust for homework, research, and engineering.
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Step-by-Step SolutionsWhere applicable, see not just the answer but the calculation steps. Perfect for learning and verifying your own work.
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Instant ComputationComplex calculations that take minutes by hand are solved in milliseconds. Explore different scenarios and parameters quickly.
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Great for StudentsWhether you're in high school physics or graduate-level engineering, Series & Parallel Resistor Calculator helps you check your work and build intuition for the underlying concepts.
Frequently Asked Questions
In a series circuit, components are connected end-to-end so the same current flows through all of them. Total resistance is the sum of all individual resistances: R_total = R1 + R2 + R3. The voltage is divided across each resistor proportionally (V = IR). A break in any component stops the entire circuit — like old Christmas lights.
In a parallel circuit, components share the same two nodes, so the same voltage appears across all of them. The current divides between branches. Total resistance: 1/R_total = 1/R1 + 1/R2 + ... The total resistance is always less than the smallest individual resistor. Adding more parallel branches always decreases total resistance.
Series connections are used when you need the same current through all components (e.g., current-limiting resistors in LED circuits). Parallel connections are used when you need the same voltage across components (e.g., household outlets). Most practical circuits are a combination — like series resistors within parallel branches.