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Series & parallel circuits

Capacitor Calculator

Find equivalent capacitance for 2 to 20 ideal capacitors in a single series or parallel group.

Calculate equivalent capacitance

Capacitor 1
Capacitor 2
2 of 20 capacitors

Every capacitance must be greater than zero. Each row can use its own unit. Use a period for decimals; grouped numbers such as 1,000.50 are accepted.

Example: 10 µF and 20 µF in parallel → 30 µF.

Equivalent capacitance

Enter at least two capacitors, then select Calculate.

≈ marks display rounding. Calculations run in your browser. Press Enter to calculate. Successful results appear in this tab's Recent calculations.

Examples and formulas

Parallel capacitance

C = C₁ + C₂ + … + Cₙ

10 µF + 20 µF = 30 µF. A parallel group's capacitance is greater than every individual positive capacitance.

Series capacitance

C = 1 ÷ (1/C₁ + 1/C₂ + … + 1/Cₙ)

For 10 µF and 20 µF, C = 20/3 µF ≈ 6.666667 µF. The result is less than the smallest individual capacitance.

Convert units before combining

1 F = 1,000 mF = 1,000,000 µF = 1,000,000,000 nF = 1,000,000,000,000 pF.

For example, 100 nF and 0.2 µF in parallel give 300 nF, or 0.3 µF.

Method and limits

This calculator accepts 2 to 20 finite, positive capacitances in one series group or one parallel group. It does not determine a network's topology or solve mixed networks automatically. Zero and negative capacitances are outside its input model.

Results assume ideal, constant capacitance. ESR, leakage, tolerance, voltage ratings, balancing, polarity, and changes with frequency or bias are not modeled. The result is not a prediction of DC charging behavior or a component voltage rating.

Inputs allow up to 15 digits before the decimal point, 10 after it, and 64 characters overall. Expressions and scientific notation are not accepted. Unit conversions and arithmetic retain exact fractions. Only displayed values are rounded, with halfway values rounded up. Trailing zeros are removed; ≈ indicates rounding. Changing the result unit or decimal places redisplays the retained result without adding a recent calculation.

Formula reference: OpenStax, University Physics Volume 2, section 8.2. Unit references: NIST SI prefixes and NIST SI derived units. References checked October 3, 2026.

Frequently asked questions

What happens with identical capacitors?

For n capacitors of capacitance C, the equivalent is n × C in parallel and C/n in series. Four 10 µF capacitors give 40 µF in parallel or 2.5 µF in series.

Why can a positive result display as zero?

A small value can round to zero in a large unit or at low precision. The ≈ symbol and result note distinguish this from an exact zero. Choose a smaller unit, increase decimal places, or open the exact value.

Can I use the result for a mixed circuit?

Calculate each identifiable series or parallel group separately. This tool does not identify those groups. Reusing rounded results can introduce error; retain an exact value or enough precision for the next calculation.

Does a series connection increase the voltage rating?

This calculator does not combine voltage ratings or determine how voltage is shared. Capacitance alone is insufficient to account for leakage, tolerance, and balancing. Consult component specifications for those design decisions.