Net ionic equation calculator
A net ionic equation shows only the chemical species that actually change during a reaction in solution.
Run — free
Starting from the aqueous ions written on each side of a full ionic equation, this calculator cancels spectator ions that appear identically among reactants and products and returns the remaining net ionic equation as a single string. Precipitation, neutralization, and many redox-in-solution drills all reduce to that cancellation once every strong electrolyte is already split into ions. Students, tutors, and exam-prep scripts need a deterministic answer that fails loudly when a listed ion has an invalid charge format instead of silently dropping the token. The same pure parse logic powers the free browser widget and the API path, so a homework check and a production grader never disagree on whether Na+ is a spectator or whether Na++ is garbage input.
How to use it
Enter your values in the form above. The tool checks them before calculating and shows the result on the same page.
Check your inputs
Use the labels and units shown next to each field. If something is missing or outside the allowed range, the page points to the field to fix.
Use it again or automate it
Use the browser tool for individual checks and the API when you need the same capability in an automated workflow.
What you can do with it
Get an answer now
Enter one set of values and see the result without building a spreadsheet or script.
Compare scenarios
Change one value at a time and rerun the calculation to understand what affects the result.
Automate repeated work
Use the API when the same calculation needs to run inside your product or workflow.
FAQ
How do I use this capability?
Complete the fields above and run it on this page. The form highlights anything that needs attention.
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/chem/net-ionic-equation \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"reactants":[{"ion":"Ag+","coefficient":1},{"ion":"NO3-","coefficient":1},{"ion":"Na+","coefficient":1},{"ion":"Cl-","coefficient":1}],"products":[{"ion":"AgCl(s)","coefficient":1},{"ion":"Na+","coefficient":1},{"ion":"NO3-","coefficient":1}]}'const res = await fetch("https://api.kit.forhosting.com/chem/net-ionic-equation", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"reactants": [
{
"ion": "Ag+",
"coefficient": 1
},
{
"ion": "NO3-",
"coefficient": 1
},
{
"ion": "Na+",
"coefficient": 1
},
{
"ion": "Cl-",
"coefficient": 1
}
],
"products": [
{
"ion": "AgCl(s)",
"coefficient": 1
},
{
"ion": "Na+",
"coefficient": 1
},
{
"ion": "NO3-",
"coefficient": 1
}
]
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/chem/net-ionic-equation",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"reactants": [
{
"ion": "Ag+",
"coefficient": 1
},
{
"ion": "NO3-",
"coefficient": 1
},
{
"ion": "Na+",
"coefficient": 1
},
{
"ion": "Cl-",
"coefficient": 1
}
],
"products": [
{
"ion": "AgCl(s)",
"coefficient": 1
},
{
"ion": "Na+",
"coefficient": 1
},
{
"ion": "NO3-",
"coefficient": 1
}
]
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/chem/net-ionic-equation", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"reactants":[{"ion":"Ag+","coefficient":1},{"ion":"NO3-","coefficient":1},{"ion":"Na+","coefficient":1},{"ion":"Cl-","coefficient":1}],"products":[{"ion":"AgCl(s)","coefficient":1},{"ion":"Na+","coefficient":1},{"ion":"NO3-","coefficient":1}]}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"reactants":[{"ion":"Ag+","coefficient":1},{"ion":"NO3-","coefficient":1},{"ion":"Na+","coefficient":1},{"ion":"Cl-","coefficient":1}],"products":[{"ion":"AgCl(s)","coefficient":1},{"ion":"Na+","coefficient":1},{"ion":"NO3-","coefficient":1}]}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/chem/net-ionic-equation", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"reactants": [
{
"ion": "Ag+",
"coefficient": 1
},
{
"ion": "NO3-",
"coefficient": 1
},
{
"ion": "Na+",
"coefficient": 1
},
{
"ion": "Cl-",
"coefficient": 1
}
],
"products": [
{
"ion": "AgCl(s)",
"coefficient": 1
},
{
"ion": "Na+",
"coefficient": 1
},
{
"ion": "NO3-",
"coefficient": 1
}
]
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "chem.net_ionic_equation",
"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_items | 40 |
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. |