高速＆高精度な化学ツール
分子量・ モル質量計算ツール
化学式を入力するだけで、分子量、モル質量、元素質量パーセント、原子数を小数第4位まで瞬時に計算します。
118元素
IUPAC標準原子量
4桁精度
高精度計算
100% ブラウザ処理
即時＆安全
分子量
全118元素対応 · IUPAC 2021標準原子量
クイック例:
上に化学式を入力して分子量を計算します
Features
Why Choose Our Calculator
118 Elements Supported
Comprehensive periodic table database with official IUPAC 2021 standard atomic weights.
Nested Groups & Brackets
Recursive descent parser handles complex parentheses, square brackets [], and curly braces {}.
Elemental Composition %
Instant mass percentage calculations for elemental analysis and stoichiometry problems.
Export & Print Reports
Copy results directly to clipboard or print formatted molecular mass breakdown PDF reports.
Step-by-Step Guide
How to Calculate Molecular Weight
Calculate chemical formula mass in three simple steps.
Enter Your Chemical Formula
Type any formula using standard chemical notation — e.g. H2O, Ca(OH)2, or K4[Fe(CN)6].
Ca(OH)₂
↓
Ca × 1O × 2H × 2
Database
Popular Chemical Compounds
Quickly view molecular weights for frequently calculated substances.
FAQ
Frequently Asked Questions
Find answers to common questions about molecular weight calculations and chemistry formulas.
Molecular weight is the sum of the atomic weights of all atoms in a chemical formula, expressed in g/mol or Daltons (Da).
Multiply each element's atomic weight by its atom count in the formula and sum the total.
Molecular weight measures a single molecule in Daltons while molar mass measures one mole in g/mol; both share equal numerical values.
Molecular weight is measured in grams per mole (g/mol), Daltons (Da), or atomic mass units (amu).
This calculator uses standard IUPAC 2021 atomic weights precise to 4 decimal places.
Calculations are accurate to 4 decimal places following official IUPAC 2021 standards.
Yes, this calculator is 100% free to use with no sign-up or usage limits.