Mixing two solutions calculator
100 mL of a 2 M solution poured into 300 mL at 0.5 M give 400 mL at 0.875 M. Enter the concentration and volume of each solution and get the mixture's strength, weighted by volume rather than a plain average. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- C1
- 2
- V1
- 100
- C2
- 0.5
- V2
- 300
- Concentration
- 0.875
- Total volume
- 400
- Total amount
- 350
- Amount1
- 200
When two solutions that contain the same solute are poured together, the final concentration is not a simple average of the two labels unless the volumes happen to match. Solute is conserved, so the mixture concentration equals the total solute amount divided by the total volume: C equals open parenthesis c1 times v1 plus c2 times v2 close parenthesis over open parenthesis v1 plus v2 close parenthesis. This capability accepts the four numbers, returns the weighted result with intermediate amounts, and rejects a zero total volume so pipelines never divide by an empty flask.
How the mixing formula works and what units to keep consistent
Write both solutions in the same concentration unit and the same volume unit before you call the calculator. Typical classroom pairs are molar with milliliters, percent weight per volume with milliliters, or milligrams per liter with liters—the arithmetic is the same as long as both sides speak the same language. Concentration of solution one is field c1, its volume is v1; solution two uses c2 and v2.
Because the solute does not disappear when the liquids combine, the amount contributed by the first vessel is c1 times v1 and the amount from the second is c2 times v2. Their sum is the numerator; the sum of volumes is the denominator. Leaving a required field blank also fails so the engine never guesses a stock strength.
Identical inputs always produce identical outputs because there is no network call, no model, no random seed, and no wall clock in the path. A common worked example is mixing one hundred milliliters of a two molar solution with three hundred milliliters of a zero point five molar solution of the same salt, which yields a half molar mixture after the weighted average.
What you can do with it
Lab prep when combining two stocks
Technicians enter two stock concentrations and pour volumes; the calculator returns the resulting mixture concentration before labeling the combined bottle.
FAQ
What happens if total volume is zero?
When v1 + v2 is zero there is no mixture volume, so the concentration is undefined and the engine refuses to divide by zero.
Do both solutions need the same units?
Yes. Keep concentration units consistent for c1 and c2, and volume units consistent for v1 and v2. The engine does not convert units for you.
Is the mixing two solutions calculator free?
The browser tool runs free on your device.
How is this different from a dilution calculator?
Dilution solves M1V1=M2V2 when you add solvent to one stock. This calculator mixes two solutions that already contain the same solute, using a volume-weighted average of their concentrations.
Why is the result not the simple average of the two concentrations?
Because each solution counts in proportion to its volume. The solute amounts are added and divided by the total volume, so only equal volumes give the plain average of the two labels.
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/chem/mixing-two-solutions \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"c1":2,"v1":100,"c2":0.5,"v2":300}'const res = await fetch("https://api.kit.forhosting.com/chem/mixing-two-solutions", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"c1": 2,
"v1": 100,
"c2": 0.5,
"v2": 300
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/chem/mixing-two-solutions",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"c1": 2,
"v1": 100,
"c2": 0.5,
"v2": 300
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/chem/mixing-two-solutions", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"c1":2,"v1":100,"c2":0.5,"v2":300}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"c1":2,"v1":100,"c2":0.5,"v2":300}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/chem/mixing-two-solutions", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"c1": 2,
"v1": 100,
"c2": 0.5,
"v2": 300
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "chem.mixing_two_solutions",
"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.
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
Homework checkers, lab prep sheets, LIMS scripts, and teaching apps can pin the same JSON in tests without embedding a chemistry CAS.
How the mixing formula works and what units to keep consistent
Send a JSON object with all four fields as finite non-negative numbers; aliases such as concentration1, volume2, C1, and vol1 are accepted when documented by the SDK so client code can speak laboratory English. Negative concentrations or volumes fail with invalid_input rather than inventing a physical meaning.
Reading the response: concentration, totals, and zero-volume errors
Concentrations and volumes are pure numbers: the engine does not convert molar to millimolar or milliliters to liters, so keep units aligned yourself and document them in your own interface. On success the response echoes numeric c1, v1, c2, and v2, then reports concentration as the mixture result after stable nine-decimal rounding. total_volume is v1 plus v2, total_amount is the conserved solute measure c1 times v1 plus c2 times v2, and amount1 with amount2 break that sum so a UI can show each flask’s contribution without re-multiplying. The equation field restates C equals open parenthesis c1·v1 plus c2·v2 close parenthesis over open parenthesis v1 plus v2 close parenthesis, and method is always mixing_two_solutions so downstream routers can branch without sniffing shapes. Use concentration alone when a form only needs the final label on the mixed bottle; use the full payload when a prep sheet must print both stocks, both volumes, and the check totals together. If total volume is zero—both volumes zero, or any pair that sums to zero—the request fails with invalid_input and a message that names the zero total volume condition, so technicians can correct an empty entry without reading a stack trace. Validation failures are not charged after the engine rejects the request.
API usage, pricing, lab workflows, and how this differs from dilution
Call the free in-browser mixing two solutions calculator for homework checks, lecture demos, and quick bench prep without installing a spreadsheet formula library. Multi-stage blends of three or more stocks are not modeled inside one call—run the identity pairwise or expand the sum yourself—because each two-solution step is still the same four-variable relation. Authors shipping SDKs can map the four fields into labeled inputs Solution 1 concentration, Solution 1 volume, Solution 2 concentration, and Solution 2 volume with the mixture concentration auto-filled—the same columns students write when they apply the mixing formula by hand on paper. Send a JSON body with c1, v1, c2, and v2 as numbers or numeric strings. Use the prepaid API when a LIMS integration, tutoring platform, media kitchen planner, or inventory system needs a stable contract under KIT balance at $0.002 per successful item; validation failures never consume balance after the engine rejects the request. This product is not the same search intent as a dilution calculator: dilution rearranges M1V1 equals M2V2 when you add pure solvent to one stock, whereas mixing two solutions assumes both vessels already carry solute and combines them by weighted average. Pair this endpoint with unit conversion helpers in your own pipeline when the next step is converting percent to molarity before the mix.
Integration use cases
Homework and exam verification
Students solve weighted-average mixture problems and compare against structured JSON, with a clear error when total volume is zero.
LIMS and teaching app integrations
Scripts and curriculum tools call a stable prepaid endpoint instead of reimplementing the mixing formula in every language and spreadsheet.
Technical questions
How do I calculate the concentration after mixing two solutions?
Send JSON with c1, v1, c2, and v2. The response returns concentration = (c1·v1 + c2·v2) / (v1 + v2), plus total_volume and the solute amount contributions.