Chemistry calculator

Mole Calculator

Q: Is this molarity?

No. Molarity c = n/V is /calc/chemistry/molarity. This page is amount of substance.

Q: Does this rewrite the chemistry converters?

No. /convert/chemistry pair pages such as ppm stay converters. This page is amount of substance.

Q: What is N_A?

The Avogadro constant 6.02214076×10²³ mol⁻¹, exact in CODATA 2018.

Q: Where does this run?

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

Compute amount n = m/M and particle count N = n·N_A. N_A is CODATA 2018 exact. Runs locally. Not molarity and not Henderson–Hasselbalch.

Instant result

Result

—

Enter values to calculate.

Inputs—

Mode—

Formula—

Trust summary Engine tested · Source checked · 12/12 tests · Production surface contract 3/3 · v1.0.0

Input interpretation: Enter values to calculate.
Result: —
Model: Amount of substance from mass or particle count, and the inverse mass and particle relations.
Scope: n = m/M
Verification: Engine tested · 12/12 tests · Production surface contract 3/3 · Source checked · v1.0.0
Named expert review: Optional · Not performed
Sources: CODATA 2018 — Avogadro constant — N_A
IUPAC Gold Book — mole — amount of substance
OpenStax Chemistry 2e — Formula Mass and the Mole Concept — The mole
Sources
Evidence: 1 golden · 6 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Production: Embedded snapshot: unpublished · Build schema 1.0.0 ready · Semantic contract ✓ · Attestation report not published on origin · Live production status PASS (0 stale; 164 CURRENT) @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.

From massn = m / M

AvogadroN = n · N_A

iLab units: mass in grams, M in g/mol, n in mol. This page is not molarity c = n/V.

How to use

Choose mass or particles

m → n needs mass and M. N → n needs an entity count.

Enter the known values

M must be greater than zero. Mass, amount, and particle count may be zero.

Read n and N

n = m/M. N = n·N_A.

Example calculations

Common configurations with formula and result.

Two moles of water-like M

m=36.03 g, M=18.015 g/mol

n = 36.03 / 18.015

n=2 mol

One mole of entities

N = N_A

n = N / N_A

n=1 mol

Mole calculator specification

Version 1.0.0 · Engine tested

Calculation status

Engine tested 12/12 tests · Production surface contract 3/3
Named expert review Not performed
Calculation version 1.0.0

Review policy · Evidence

Definition: Amount of substance n = m/M. Entity count N = n·N_A with N_A = 6.02214076×10²³ mol⁻¹ (CODATA 2018 exact).
What it calculates: Amount of substance from mass or particle count, and the inverse mass and particle relations.
Inputs: mode?
mass
molar_mass
amount
particles
Outputs: amount
mass?
particles?
N_A
Formula: n = m/M; N = n·N_A
Assumptions: n = m/M
N = n·N_A
N_A = 6.02214076e23 (CODATA 2018 exact)
Lab units g, g/mol, mol
Not molarity or dilution
Not ICE or Henderson–Hasselbalch
Units: g
g/mol
mol
count
Boundary conditions: from_mass missing mass or molar_mass → MISSING_REQUIRED_INPUT
molar_mass ≤ 0 → VALUE_MUST_BE_POSITIVE
unknown mode → INVALID_MODE
mass, amount, or particles < 0 → VALUE_OUT_OF_RANGE
Example: mass=36.03 molar_mass=18.015 → n=2
Validation cases: 3 published on this page · 12/12 tests · Production surface contract 3/3 · View evidence
mass=36.03 molar_mass=18.015 → n=2
mode=from_particles particles=N_A → n=1
molar_mass=0 → VALUE_MUST_BE_POSITIVE
Sources: CODATA 2018 — Avogadro constant — N_A
Supports: N_A = 6.02214076×10²³ mol⁻¹ exactly
IUPAC Gold Book — mole — amount of substance
Supports: The mole is the SI unit of amount of substance; n = N/N_A
OpenStax Chemistry 2e — Formula Mass and the Mole Concept — The mole
Supports: n = m/M relates mass, molar mass, and amount
Calculation version: 1.0.0

Background

Interpretation and common distinctions.

Compute amount of substance from mass or particle count.

Supported and not supported

Supported — n = m/M and N = n·N_A · API chemistry.mole.amount

Not supported — molarity, dilution, ICE, Henderson–Hasselbalch, rewriting /convert/chemistry

Agent / API notes

Capability id: chemistry.mole.amount · tool id: mole · pin 1.0.0.

{ "mode": "from_mass", "mass": 36.03, "molar_mass": 18.015 }

Other modes: to_mass, from_particles, to_particles. Errors: MISSING_REQUIRED_INPUT, INVALID_NUMBER, VALUE_MUST_BE_POSITIVE, VALUE_OUT_OF_RANGE, INVALID_MODE.

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

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

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Frequently asked questions

Key distinctions behind the calculation.

Is this molarity?