Case 1
- First capacitance C1 (F)
- 2F
- Second capacitance C2 (F)
- 3F
1.200000F
Open with these valuesSeries Capacitance Calculator
Change any value to update the result.
1.200000F
Total series capacitance: 1.200000 FExamples
How the result moves
Second capacitance C2 (F) (F) → Total series capacitance (F)Your current valid inputs, with one value varied across the range.
How the result moves
Held fixed: First capacitance C1 (F) 2.000000000000 F.
| Second capacitance C2 (F) (F) | Total series capacitance (F) |
|---|---|
| 2.000000000000 | 1.000000 |
| 3.000000000000Your value | 1.200000 |
| 4.000000000000 | 1.333333 |
Capacitors in series follow product over sum: 2 F and 3 F give 6 ÷ 5 = 1.2 F, below either part. That is the same arithmetic as resistors in parallel, and the reverse of capacitors in parallel, which simply add. In series the voltage splits, so the pair withstands more than one alone.
Worked examples
Case 2
- First capacitance C1 (F)
- 4F
- Second capacitance C2 (F)
- 4F
2.000000F
Open with these valuesCase 3
- First capacitance C1 (F)
- 6F
- Second capacitance C2 (F)
- 3F
2.000000F
Open with these valuesHow it's calculated
C = (C1 × C2) ÷ (C1 + C2)
- StepEnter both capacitances in farads — 100 µF is 0.0001 F.
- StepMultiply the two values, then divide by their sum.
- ResultRead the total; it always falls below the smaller capacitor.1.200000F
Reference table
| C1 (F), C2 (F) | What it is | Total (F) |
|---|---|---|
| 1, 1 | half of one part | 0.5 |
| 2, 3 | the default pair | 1.2 |
| 4, 4 | two equal parts | 2 |
| 6, 3 | unequal, same result | 2 |
| 10, 10 | two equal parts | 5 |
Questions
How do two capacitors in series combine?
By the product-over-sum rule: C = (C1 × C2) ÷ (C1 + C2). For 2 F and 3 F that is 6 ÷ 5 = 1.2 F. Capacitors sit in series when the same charge flows through both, and they then combine exactly like resistors in parallel.
Why is the total smaller than either capacitor?
Wiring capacitors end to end effectively increases the plate separation, and capacitance falls as the plates move apart. The pair therefore stores less charge per volt than either part alone. Two 2 F capacitors in series give 1 F.
What happens when both capacitors are equal?
The total is exactly half of one of them, because C times C over C plus C is C ÷ 2. Two 4 F capacitors give 2 F and two 10 F capacitors give 5 F.
How is series different from parallel for capacitors?
It is the opposite. In parallel you add the values and the total grows above either part; in series the total falls below the smaller one. For capacitors, series behaves like parallel resistors and parallel behaves like series resistors.
Does wiring capacitors in series raise the voltage rating?
Yes. In series the applied voltage splits across the capacitors, so each one sees only part of the total. That is why series connections are used to exceed the rating of a single part, at the cost of a smaller total capacitance.