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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 CVP VERIFIED · CVP protocol 1.0.0-proposed · Engineering assurance · c = n/V and one-unknown C1·V1 = C2·V2, + O3 mpmath tabulated molarity.
Input interpretation
Enter values to calculate.
Result
—
Verified scope
c = n/V and one-unknown C1·V1 = C2·V2, + O3 mpmath tabulated molarity.
Assurance
Engineering
Declared partition coverage
PASS · 9/9 declared partitions (alias, zero, amount-mode, volume-mode, dilution-v2, dilution-other, awkward, molarity, invalid-domain) · Matrix
Deferred
Not mole n = m/M and not a buffer.
Numerical scope
O2: molarity c = n/V and one-unknown dilution vs a separate-module identity (≤2 ULP). Not mole n = m/M. ≤2 ULP vs O3 applies only to the published tabulated molarity vectors. Not mole n = m/M.
Known limitations
  • Core CVP does not include live graph, viewport, or pointer interaction.
Model
Molarity from amount and volume, the inverse n or V, and one-unknown dilution.
Scope
c = n/V
Verification
Engine tested · Source checked · v1.0.1 · CVP VERIFIED · CVP protocol 1.0.0-proposed · Engineering assurance · c = n/V and one-unknown C1·V1 = C2·V2, + O3 mpmath tabulated molarity.· View Manifest · CVP overview · Specification
Versions
Calculation 1.0.1 · CVP protocol 1.0.0-proposed · Evidence 2026-09-25.o2-o3.2
Verification revision
2026-09-25.o2-o3.2 · 1/1 property · digest 186290957d37
Legacy regression
14/14 tests · Production surface contract 5/5
Trust layers
Verification VERIFIED · Production CURRENT · Overall CVP state: VERIFIED under CVP 1.0.0-proposed
Reference
O1 model · O3 expected_values · O3 numerical_behavior · O2 expected_values · O2 numerical_behavior
Interfaces
PASS · UI (SSR) / REST / MCP — ui-ssr is query-result HTML, not a live browser session. Error-path engine·REST·MCP 1/1 (status, code, calculation_version). SSR compared on URL-canonical requested calculations; empty query is idle (not an error) and JSON-typed object/array inputs are REST/MCP-only.
Supplemental domain review
Not performed
Named expert review
Not performed
CVP suite
4/4 golden · 7/7 CVP boundary · 6/6 invalid · 1/1 property · 1/1 metamorphic · 8/8 O3 · 2/2 cross-interface · 5/5 CVP contract · Manifest
Sources
Sources
Evidence
1 legacy golden · 8 legacy boundary · legacy regression suite · 4/4 oracle-backed golden · 6/6 invalid · Artifact integrity PASS
This calculator CURRENT · Public schema 1.0.1 matches · Semantic contract ✓ · Production attested · Public/cache ✓ · Origin ✓
Semantic contract
PASS
Full verification

Manifest identity, reference classes, interfaces, suite, and production records.

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

1

Choose molarity or dilution

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

2

Enter the known values

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

3

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.

ϟ

Two-molar solution

n=0.5 mol in V=0.25 L

c = 0.5 / 0.25
c=2 mol/L
ϟ

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 1.0.1 · Engine tested

Calculation status

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 5/5 · 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
Calculation version
1.0.1

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 1.0.1.

{ "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 .

n Mole › pH Henderson–Hasselbalch › pH pH ›

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.