Periodic table & molar mass
An interactive periodic table — click any element for its atomic number, weight, group, period and block — plus a chemical-formula parser that works out molar mass and percent composition, including nested groups like Ca(OH)₂ and hydrates like CuSO₄·5H₂O. Runs entirely in your browser.
Open Periodic table & molar mass →What is the periodic table & molar mass tool?
An interactive periodic table with a built-in molar mass calculator. Click any element to see its atomic number, weight, group, period and block, then type a chemical formula to work out its molar mass and percent composition — including nested groups like Ca(OH)₂ and hydrates like CuSO₄·5H₂O. Standard atomic weights are embedded and it runs entirely in your browser, so nothing is fetched or uploaded.
How to use Periodic table & molar mass
- Explore the table — Browse all 118 elements, colour-coded by category. Click any cell to open its details panel.
- Search for an element — Type a name, symbol or atomic number in the search box to highlight the element you want, and use the legend to focus on a category.
- Read the details — The detail panel shows the element's atomic number, atomic weight, group, period and block at a glance.
- Calculate molar mass — Type a chemical formula into the molar mass calculator. Use the · button to insert a hydrate dot — for example CuSO4·5H2O.
- Check the breakdown — Read off the total molar mass plus a per-element percent composition table for the formula you entered.
Frequently asked questions
Does it need an internet connection?
No. The standard atomic weights are embedded in the tool, so nothing is fetched or uploaded and it works fully offline after the first load.
Can it handle brackets and hydrates?
Yes. The formula parser understands nested groups like Ca(OH)2 and hydrates written with a dot, such as CuSO4·5H2O. Use the · button to insert the hydrate dot.
What does the percent composition table show?
It lists each element in your formula alongside the percentage of the total molar mass that it contributes, so you can see what fraction of the compound's mass comes from each element.
How many elements are included?
All 118 elements are in the table, each colour-coded by category — alkali metals, noble gases, halogens, transition metals, lanthanides, actinides and more.
How do I find a specific element quickly?
Type its name, symbol or atomic number into the search box and the matching cell is highlighted in the grid.
Tips
- Use the · button instead of typing the dot manually when entering a hydrate formula.
- Click a category in the legend to dim everything else and focus on one group of elements.
- Atomic symbols are case-sensitive — Co is cobalt, while CO is carbon plus oxygen.