Chemistry calculator

Molarity Calculator

Compute molarity c = n/V and dilution C1·V1 = C2·V2. Runs locally. Not mole n=m/M and not Henderson–Hasselbalch.

Instant result

Result

—

Enter values to calculate.

Inputs—

Mode—

Formula—

Trust summary Engine tested · Source checked · 14/14 tests · Production surface contract 3/3 · v1.0.0

Input interpretation: Enter values to calculate.
Result: —
Model: Molarity from amount and volume, the inverse n or V, and one-unknown dilution.
Scope: c = n/V
Verification: Engine tested · 14/14 tests · Production surface contract 3/3 · Source checked · v1.0.0
Named expert review: Optional · Not performed
Sources: OpenStax Chemistry 2e — Molarity — Molarity
OpenStax Chemistry 2e — Dilution of Solutions — Dilution
IUPAC Gold Book — concentration — amount concentration
Sources
Evidence: 1 golden · 8 boundary · 5 property · Production surface contract 3/3 · Artifact integrity PASS
Production: Embedded snapshot: unpublished · Build schema 1.0.0 ready · Semantic contract ✓ · Attestation report not published on origin · Live production status PASS (0 stale; 164 CURRENT) @ 2026-09-16T06:44:24.909Z
Semantic contract: PASS

Formulas

Core equations used by this calculator.

Molarityc = n / V

DilutionC1 · V1 = C2 · V2

iLab units: n in mol, V in L, c in mol/L. This page is not mole n = m/M.

How to use

Choose molarity or dilution

c = n/V needs amount and volume. Dilution omits exactly one of C1, V1, C2, V2.

Enter the known values

Volume and concentrations used as divisors must be greater than zero. Amount may be zero.

Read c or the omitted dilution term

c = n/V. Dilution solves the missing C1, V1, C2, or V2.

Example calculations

Common configurations with formula and result.

Two-molar solution

n=0.5 mol in V=0.25 L

c = 0.5 / 0.25

c=2 mol/L

Stock to working concentration

C1=2 mol/L, V1=0.05 L, C2=0.1 mol/L

V2 = C1·V1 / C2

V2=1 L

Molarity calculator specification

Version 1.0.0 · Engine tested

Calculation status

Engine tested 14/14 tests · Production surface contract 3/3
Named expert review Not performed
Calculation version 1.0.0

Review policy · Evidence

Definition: Molarity c = n/V. Dilution conserves solute: C1·V1 = C2·V2. Lab units mol, L, mol/L.
What it calculates: Molarity from amount and volume, the inverse n or V, and one-unknown dilution.
Inputs: mode?
amount
volume
molarity
c1
v1
c2
v2
Outputs: molarity?
amount?
volume?
c1?
v1?
c2?
v2?
solved_field?
Formula: c = n/V; C1·V1 = C2·V2
Assumptions: c = n/V
C1·V1 = C2·V2
Lab units mol, L, mol/L
Not mole n=m/M
Not ICE or Henderson–Hasselbalch
Units: mol
L
mol/L
Boundary conditions: molarity missing amount or volume → MISSING_REQUIRED_INPUT
volume ≤ 0 → VALUE_MUST_BE_POSITIVE
dilution with 0 or 2+ omitted keys → INVALID_INPUT
unknown mode → INVALID_MODE
Example: amount=0.5 volume=0.25 → c=2
Validation cases: 3 published on this page · 14/14 tests · Production surface contract 3/3 · View evidence
amount=0.5 volume=0.25 → c=2
mode=dilution c1=2 v1=0.05 c2=0.1 → v2=1
volume=0 → VALUE_MUST_BE_POSITIVE
Sources: OpenStax Chemistry 2e — Molarity — Molarity
Supports: c = n/V relates amount, volume, and molar concentration
OpenStax Chemistry 2e — Dilution of Solutions — Dilution
Supports: C1·V1 = C2·V2 conserves solute amount on dilution
IUPAC Gold Book — concentration — amount concentration
Supports: Amount concentration is amount of substance divided by volume
Calculation version: 1.0.0

Background

Interpretation and common distinctions.

Compute molarity and dilution.

Supported and not supported

Supported — c = n/V and C1·V1 = C2·V2 · API chemistry.solution.molarity

Not supported — mole n=m/M, ICE, Henderson–Hasselbalch, rewriting /convert/chemistry

Agent / API notes

Capability id: chemistry.solution.molarity · tool id: molarity · pin 1.0.0.

{ "mode": "molarity", "amount": 0.5, "volume": 0.25 }

Other modes: amount, volume, dilution. Dilution omits exactly one of c1, v1, c2, v2. Errors: MISSING_REQUIRED_INPUT, INVALID_NUMBER, VALUE_MUST_BE_POSITIVE, VALUE_OUT_OF_RANGE, INVALID_MODE, INVALID_INPUT.

Calculator URL is /calc/chemistry/molarity. Converters stay on /convert/chemistry.

Other calculators in this family: Mole, Henderson–Hasselbalch, pH .

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Frequently asked questions

Key distinctions behind the calculation.

Is this mole n = m/M?

No. Amount from mass is /calc/chemistry/mole. This page is solution concentration.

Does dilution use four given values?

No. Provide exactly three of C1, V1, C2, V2. Sending all four is rejected.

Is this ICE or Henderson–Hasselbalch?

No. Buffer pH is /calc/chemistry/henderson-hasselbalch. ICE is out of scope.

Where does this run?

Locally in the browser by default. REST and MCP call the same chemistry-engine solution wrapper.