Series Capacitance Calculator

Combine capacitors in series with 1/Ctot = 1/C1 + 1/C2 + ..., see how the total drops below the smallest capacitor, and get the equal charge Q, the voltage across each capacitor Vi = Vtot x Ctot / Ci, and the energy stored E = 0.5 x Ctot x V squared. The calculator flags the capacitor under the highest voltage stress.

🎯Real Series Capacitor Presets

🔌Series Capacitor Inputs

Number of capacitors in series

More capacitors in series lower the total further.

Capacitance unit

Applies to every capacitor value C1 to C5.

Capacitor C1 value

First capacitor in the series string.

Capacitor C2 value

Second capacitor in the series string.

Capacitor C3 value

Shown when 3 or more capacitors are selected.

Capacitor C4 value

Shown when 4 or more capacitors are selected.

Capacitor C5 value

Shown when 5 capacitors are selected.

Applied total voltage (V)

DC voltage across the whole series string.

Result significant figures

Controls rounding on every result card.

Total series capacitance 0 Ctot from 1/Ctot = sum 1/Ci

Total charge Q 0 Q = Ctot x V, equal on each cap

Highest voltage stress 0 V across the smallest capacitor

Energy stored E 0 E = 0.5 x Ctot x V squared

🔢Formula Snapshot

Ctot1 / sum(1/Ci)

QCtot × V

ViQ / Ci

E0.5 C V²

📋Why Series Lowers Capacitance

Equal Caps	Count n	Ctot = C / n	Reads As
100 uF	2	50 uF	Half the value
100 uF	3	33.3 uF	One third
100 uF	4	25 uF	One quarter
100 uF	5	20 uF	One fifth
10 nF	2	5 nF	Half the value
10 nF	3	3.33 nF	One third
1 uF	4	0.25 uF	One quarter
1 uF	5	0.2 uF	One fifth

⚖Voltage Sharing Between Two Caps

C1	C2	V1 share	V2 share	Note
100 uF	100 uF	50%	50%	Equal split
1 uF	4.7 uF	82.5%	17.5%	Small sees more
1 uF	10 uF	90.9%	9.1%	Small sees more
100 pF	47 pF	32.0%	68.0%	Small sees more
10 nF	22 nF	68.8%	31.2%	Small sees more
220 nF	220 nF	50%	50%	Equal split
2.2 uF	1 uF	31.3%	68.8%	Small sees more

📏Standard Capacitor Decade Values

E6 Value	Picofarads	Nanofarads	Microfarads
1.0	100 pF	1 nF	1 uF
1.5	150 pF	1.5 nF	1.5 uF
2.2	220 pF	2.2 nF	2.2 uF
3.3	330 pF	3.3 nF	3.3 uF
4.7	470 pF	4.7 nF	4.7 uF
6.8	680 pF	6.8 nF	6.8 uF
10	1000 pF	10 nF	10 uF

🗃Two-Cap Series Comparison Grid

C1	C2	Ctot	Q at 50 V	V1	V2
100 uF	100 uF	50 uF	2.5 mC	25 V	25 V
1 uF	4.7 uF	0.822 uF	41.1 uC	41.2 V	8.8 V
1 uF	10 uF	0.909 uF	45.5 uC	45.5 V	4.5 V
100 pF	47 pF	31.97 pF	1.6 nC	16.0 V	34.0 V
10 nF	22 nF	6.875 nF	0.344 uC	34.4 V	15.6 V
220 nF	220 nF	110 nF	5.5 uC	25 V	25 V
2.2 uF	1 uF	0.688 uF	34.4 uC	15.6 V	34.4 V
470 pF	470 pF	235 pF	11.75 nC	25 V	25 V
10 uF	10 uF	5 uF	250 uC	25 V	25 V
1 nF	1 nF	0.5 nF	25 nC	25 V	25 V

⚙Formula Breakdown

1/Ctot = sum(1/Ci)The reciprocal of the total equals the sum of the reciprocals. For 100 uF and 100 uF: 1/Ctot = 1/100 + 1/100 = 2/100, so Ctot = 50 uF.

Two caps Ctot = C1 C2 / (C1 + C2)A shortcut for exactly two capacitors, the product over the sum. For 1 uF and 4.7 uF: Ctot = 4.7 / 5.7 = 0.822 uF, below the smaller cap.

N equal caps Ctot = C / nIdentical capacitors in series divide by the count. Five 1 uF caps give 1 / 5 = 0.2 uF total.

Charge Q = Ctot x VThe same charge flows onto every capacitor in a series string. At 50 V with Ctot = 50 uF, Q = 50e-6 x 50 = 2.5 mC on each cap.

Voltage Vi = Q / Ci = Vtot x Ctot / CiBecause Q is shared, each voltage is inversely proportional to its own capacitance. The smallest capacitor takes the largest share of the applied voltage.

Energy E = 0.5 x Ctot x V squaredTotal stored energy uses the combined capacitance. At 50 V with Ctot = 50 uF, E = 0.5 x 50e-6 x 2500 = 0.0625 J.

💡Practical Series Capacitor Tips

Charge is shared, voltage is not: In a series string every capacitor carries the identical charge Q = Ctot x V, but the voltage divides in inverse proportion to capacitance. A 1 uF cap in series with a 10 uF cap across 50 V takes about 45.5 V while the 10 uF cap sees only 4.5 V, so always check each Vi against its own rating.

Add balancing resistors: When stacking capacitors for higher voltage, small tolerance and leakage differences make one cap hog the voltage. Place equal balancing resistors, often 100 kil-ohm to 1 megohm, across each capacitor so the DC voltage divides evenly and no single unit is pushed past its rating.

If you’re accustomed to working with resistors, wiring capacitors in series seems…wrong. When you put resistors end to end, they adds up linearly. Capacitators? No way, they go the other direction. The total capacitance becomes less then the smallest one in the string. This is counterintuitive. It is enough to trip up beginners and infuriate engineers looking for bigger storage capacity.

Once you know values you need, just plug them into calculator above and it’ll do the math for you, saving you the reciprocal sums in your head. And it’ll even handle bits that really count for safety in a circuit. It handles the voltage stress on each capacitor individually, as well as how charge distributes across all the caps.

How Capacitors Work in Series

It’s all based off reciprocals. The equation that governs depends on them. To calculate the combined value, you add together one over every capacitance value and then you take one over that sum. So mathematically, adding more capacitors in series will always reduce total. If you have two of the same cap, you get half the original value. If you have three, you gets a third, and so on. Capacitance does not accumulate.

That is why you do not usually see people stacking capacitors to create smaller capacitance values. They do it to withstand higher voltages. A given capacitor might only be rated at twenty volts, but if you put two in series they can handles forty if the voltage splits evenly between them. That is why the setup matter.

That’s where it begins to get dicey: Voltage Sharing. Ideally, if components were exactly alike, the voltage divides equally. But real caps are not alike. Each has a different leakage current. Each have different tolerances. When fifty volts is applied between two caps, 1 uF and 10 uF in series, neither gets an equal load. The larger cap get five volts while the smaller cap gets about forty-five.

The calculator notes difference by coloring the highest stressed voltage for you. That way you know what component to compare against ratings. You will find out when the overstressed cap burns up, sending the whole line voltage to the others until they also fail.

The solution to this problem is what engineers call “balancing resistors.” On every capacitor in the string, a large value resistor is installed in parallel with it. They act as load on all the capacitors so that even if they leak differently from one another, the DC voltage splits equally. They are small but important to prevent total disaster.

You can enter several capacitors into the tool and see clearly how the voltage splits among them. Change the number, change their values, watch how the stress moves around. That’s good when building something like a high-voltage filter or snubber network where reliability simply cannot be compromised.

The total string of capacitors have the same amount of charge. All of them passed the same current while charging, and so they all has the same charge. That charge divided by the capacitance of unit gives you the voltage drop per unit. The lower the capacitance the more voltage (for the same amount of charge).

That’s a trade off. Higher voltage headroom means less storage capacity. More voltage, less storage capacity. It has less total energy storage than one larger capacitor at the same voltage. You’re paying for the insulation distance with the storage space.

There are preset buttons that provide fast reference points. Test a mixed value tuning circuit. Load two 100 microfarad caps and double your working voltage. These are some of the example scenarios shown here. Unequal values skews the results immediately. Before you even think about soldering it’s good to get in there and run a couple of simulations.

That understanding of where the voltage is concentrating and why the total drops out will turn a confusing formula into a practical design tool. Series strings then becomes a robust solution to high-voltage applications rather than a ticking time bomb if you have the correct balancing measures in place.