About Molecular Weight Calculator
We build free, accurate and beautifully simple chemistry tools — so that students, teachers and lab professionals can spend less time on arithmetic and more time on science.
Our Mission
Chemistry shouldn’t slow down at the calculator step. Every day, millions of students and lab professionals convert formulas into molar masses, grams into moles, and recipes into solutions — and a single arithmetic slip can ruin an experiment, an exam answer, or an entire batch.
MolecularWeightCalculator.org exists to remove that friction. Our tools give you instant, verifiable answers with step-by-step working — so you don’t just get the number, you understand where it came from.
What We Offer
Molecular Weight & Composition
Enter any chemical formula — including hydrates, parentheses and brackets — and get molar mass, atom counts, percent composition and interactive graphs instantly.
Grams ↔ Moles Conversion
The bridge between the balance and the equation. Convert mass to moles and back, with molecule counts via Avogadro’s number and full working shown.
Solution Preparation
Tell us the molarity and volume you need — we hand you a ready lab recipe: exactly how many grams to weigh, dissolve and top up.
Batch Comparison
Compare up to 15 compounds side by side with sorted tables and bar charts — perfect for reports, assignments and reagent selection.
Element Mass Finder
Find out exactly how many grams of each element your sample contains — essential for fertilizer analysis, nutrition chemistry and purity checks.
Export Everything
Copy results, download CSV for Excel, save TXT, print clean reports or share directly — your work stays yours, in whatever format you need.
Why You Can Trust Our Numbers
Official IUPAC data. Every calculation uses the standard atomic weights published by IUPAC — the same values professional laboratories rely on.
Transparent working. We never hide the math. Every result shows its step-by-step derivation so you can verify it yourself.
Expert-reviewed content. Our guides and tools are written and checked by a qualified chemistry educator with 10+ years of teaching experience.
Privacy-first. All calculations run in your browser. Your formulas and results never leave your device — nothing to sign up for, nothing tracked.
Who Is Behind This Site
Founder & Chief Editor
Ahmad Raza, M.Phil. Chemistry
Ahmad is a chemistry educator and science content developer with over 10 years of experience teaching analytical and physical chemistry. He founded MolecularWeightCalculator.org after watching countless students lose marks — and lab teams lose batches — to simple molar mass slips. Every tool on this site is one he wished existed in his own classroom.
The Principles We Work By
Accuracy First
If a number appears on this site, it can be traced to an authoritative source. We publish corrections openly under our Corrections Policy.
Free Means Free
No paywalls, no locked “pro” modes, no sign-up walls. Education tools should be open to everyone, everywhere.
Teach, Don’t Just Tell
Every answer comes with its working. Our goal is that you eventually need us a little less — because you understand the chemistry more.
Get In Touch
Questions, suggestions, corrections, or a formula our parser couldn’t handle? We read every message — several of our current features started as user ideas.
You can also reach us through our contact page.
Ready to calculate? Our free molecular weight calculator is one click away.
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