Parallel capacitor calculator
Capacitors of 1, 2.2 and 4.7 µF in parallel, entered as 0.000001, 0.0000022 and 0.0000047 farads, add up to 0.0000079 farads. List each capacitor in farads and get the equivalent capacitance of the whole bank. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Capacitances
- 0.000001, 0.0000022, 0.0000047
- Quantity
- 3 F
- Equivalent capacitance
- 0.0000079
Capacitors that share the same two nodes form a parallel network: every branch sees the same voltage, stored charges add, and the equivalent capacitance is the arithmetic sum of the individual farad values. Students, technicians, and firmware authors reach for that identity when they combine ceramics, electrolytics, or film parts into a single C_eq for a filter, a decoupling bank, a supercapacitor pack, or a lab write-up. Convert microfarads, nanofarads, and picofarads to farads before you call.
What a parallel capacitor network means and why the farad values add
Two or more capacitors that share the same pair of nodes form a parallel network: each device is exposed to the identical voltage, and the total charge stored at those nodes is the sum of the charges on every branch. Capacitance is defined as charge over voltage, so when the voltage is common the charges add only if the capacitances themselves add. The closed identity this calculator implements is therefore C_eq equals C_1 plus C_2 plus every remaining farad value on the list.
Send each capacitance already converted to farads, the SI unit of capacitance; a one microfarad part is one times ten to the minus six farads, a one nanofarad part is one times ten to the minus nine farads, and a one picofarad part is one times ten to the minus twelve farads. Mixing prefixes without converting them first produces a number that looks well-formed but is wrong by three orders of magnitude, so conversion is the caller's job rather than a silent engine rewrite.
A single capacitor is a valid parallel network of length one and returns that value as the equivalent, which is useful when a bill of materials still has only one fitted branch. Zero farads is allowed and contributes nothing to the sum, matching an unused pad or a placeholder in a kit.
Where adding parallel capacitors helps in labs and design
Classrooms and tutoring platforms use a parallel capacitor calculator so learners can check C_eq equals the sum of farad values without dropping a power of ten on a microfarad-to-farad conversion. Hardware designers combining bulk electrolytic and high-frequency ceramic capacitors on a power rail want a stable SI total before they talk about ESR or voltage rating, which belong in component-selection tools rather than in this pure sum. Lesson builders produce SI-unit capacitance checks for demos, auto-graded drills, and lab write-ups without embedding a circuit simulator.
Prefer this landing when you already have every branch in farads and you want the textbook parallel identity; if your schematic mixes series and parallel groups, reduce each pure parallel group here first, then combine series strings with a dedicated series product. Failed validation does not consume balance.
What you can do with it
Decoupling banks on a power rail
Board designers add bulk and high-frequency capacitors already expressed in farads to confirm the parallel total meets the target before they discuss ESR or voltage rating.
FAQ
How does this parallel capacitor calculator get equivalent capacitance in farads?
Send capacitances as a non-empty array of non-negative numbers already in farads.
Can the list of capacitors be empty?
Missing the capacitances field fails the same way.
Do I send microfarads or farads?
Farads. Convert µF, nF, and pF yourself (divide µF by one million, nF by one billion, pF by one trillion) before calling; the engine does not rewrite prefixes.
How do I solve a circuit with capacitors in series and in parallel?
Reduce each group of capacitors that share the same two nodes here first, then combine the resulting values with a tool made for series strings. In series the capacitances add as reciprocals, so they must not be summed like a parallel bank.
Can I enter a single capacitor or a zero value?
Yes. A single capacitor is a valid parallel bank, and its own value comes back as the equivalent. A zero entry is accepted and adds nothing, which suits an unfitted position on a board. Negative values are rejected.
Related tools
For developers — API access
Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.
API endpoint
Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.
Call it from your stack
curl -X POST https://api.kit.forhosting.com/phys/parallel-capacitor \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"capacitances":[0.000001,0.0000022,0.0000047]}'const res = await fetch("https://api.kit.forhosting.com/phys/parallel-capacitor", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"capacitances": [
0.000001,
0.0000022,
0.0000047
]
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/phys/parallel-capacitor",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"capacitances": [
0.000001,
0.0000022,
0.0000047
]
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/phys/parallel-capacitor", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"capacitances":[0.000001,0.0000022,0.0000047]}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"capacitances":[0.000001,0.0000022,0.0000047]}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/phys/parallel-capacitor", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"capacitances": [
0.000001,
0.0000022,
0.0000047
]
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "phys.parallel_capacitor",
"status": "queued",
"_links": {
"result": "/tasks/tsk_…/result"
}
}The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.
Pricing
Published price — no tokens, no invented credits. A failed task is never charged.
Limits
max_n | 10000 |
max_abs | 1000000000000 |
Errors
| HTTP | Code | Meaning |
|---|---|---|
401 | unauthorized | Missing or invalid API key. |
402 | insufficient_balance | Your balance doesn't cover the task price. |
404 | unknown_type | That task type doesn't exist. |
429 | rate_limited | Too many requests. Use the webhook instead of polling. |
Technical notes
This parallel capacitor calculator accepts a non-empty list of capacitances already expressed in farads, returns the total in farads with a stable formula label, and rejects any negative entry or an empty list with invalid_input so a sign typo never masquerades as a physical result.
What a parallel capacitor network means and why the farad values add
Negative values are not a physical catalog capacitance in this product and raise invalid_input instead of being folded into the total. There is no network hop, no random seed, and no dependence on the wall clock: identical farad lists always serialize to identical JSON, which is the contract labs and continuous-integration jobs need.
Input contract, response shape, and how errors are reported
If the array is missing, not a list, or has length zero, the task fails because this product will not invent a total for an empty network. If any entry is negative, the message names the index so a spreadsheet or grader can highlight the bad cell, and that failure is not billed. Example: one microfarad, two point two microfarads, and four point seven microfarads sent as 0.000001, 0.0000022, and 0.0000047 farads yields 0.0000079 farads. Series networks use the reciprocal sum and are intentionally out of scope; do not force a series string through this parallel identity. POST a JSON body with one required field named capacitances: a non-empty array of finite non-negative numbers in farads. Aliases values, capacitors, caps, C, and list are accepted when a notebook or BOM export already uses those names, and a comma or whitespace separated string is coerced for simple text forms. Each entry may arrive as a JSON number or as a numeric string that matches a strict finite decimal pattern; empty strings, Infinity, and NaN fail with invalid_input naming the index. Magnitudes must stay within the published farad ceiling so Worker isolates remain stable on oversized junk. On success the body echoes capacitances as the rounded input list in order, count as the number of devices, equivalent_capacitance as the parallel sum in farads, unit as the string F, formula as C_eq equals C_1 plus C_2 plus dots plus C_n, and method as parallel_sum. A successful API call costs $0.002.
Where a parallel capacitor API earns its keep in labs and design
Exam-prep generators need a deterministic oracle that marks a negative entry or an empty list as invalid_input instead of silently returning zero that a buggy grader might treat as success. Keep classroom microfarad and picofarad parts converted to farads, pin the rounded equivalent_capacitance in tests, and you get reproducible electrostatic arithmetic for homework, LMS plugins, and edge workers without standing up a SPICE deck of your own.
Integration use cases
Homework and lab checks in SI farads
Students convert textbook microfarad lists to farads, submit the array, and compare equivalent_capacitance with hand-written parallel sums, including deliberate negatives that must fail.
Deterministic fixtures for graders and firmware
Courseware and embedded calculators pin known-good parallel totals in farads, plus empty-list and negative-value rejections, as continuous-integration expected JSON.
Technical questions
What if I send a negative farad value?
The task fails with invalid_input. Capacitance must be non-negative here; the message names the index of the bad entry and the call is not billed.
What does a successful parallel capacitor request cost?
The browser tool is free. API requests use prepaid KIT balance at $0.002 per successful call; invalid input is not billed.