How many elements are in the periodic table?
118. That is the number of elements with an IUPAC-approved name and symbol, from hydrogen (1) to oganesson (118).
Updated on October 7, 2026
The short answer, and what it counts
The count is 118 because the table runs without a gap from atomic number 1 to 118, and every one of those has been synthesised or found and formally named. The last four names — nihonium (113), moscovium (115), tennessine (117) and oganesson (118) — were approved by IUPAC in November 2016, which closed period 7.
Of the 118, 94 occur naturally on Earth, at least in traces; the rest exist only as atoms made in accelerators, sometimes a handful of them, lasting fractions of a second. So "118 elements exist" and "118 elements are around you" are very different claims.
The count broken down
- Named elements
- 118
- Found in nature (including traces)
- 94
- Made only in the laboratory
- 24
- Metals
- 94
- Elements with no stable nuclide
- 38
- Last four names approved
- November 2016
Can the number grow?
Yes, in principle. Laboratories in Russia, Germany, Japan and the United States are trying for element 119 and 120, which would open period 8. Nothing has been confirmed: a claim only becomes an element once a joint IUPAC/IUPAP working party agrees the discovery, which has taken years in every recent case. Until then the answer stays 118.
How to read this page
How to read the numbers here
Every value on "How many elements are in the periodic table?" comes from the source named beside its section, never from an estimate of our own with no origin.
Where the data comes from
Each section of "How many elements are in the periodic table?" names its official source; the verification date sits at the top of the page.
What the number doesn’t tell you
Atomic weight, molar mass and standard uncertainty are measurement concepts: none of them say anything about a real sample’s purity, physical state or specific isotope.
More about “How many elements are in the periodic table?”
When the elements were discovered
Of the 118 elements, 24 were already known before 1800 (the metals and carbon known since antiquity, plus the first ones isolated by modern chemistry), 80 were discovered or made in the 20th century, and 5 only in the 21st. The most recent to get a name and symbol was Ts, in 2010.
That spread is why "118 elements" isn’t a list closed long ago: more than two decades into the 21st century have already produced a new element, and "How many elements are in the periodic table?" is the same page that explains why element 119 still hasn’t arrived.
Words on this page
Atomic number
The number of protons in an atom’s nucleus, written Z. It is this number, not the mass, that defines which element an atom is: every atom with 8 protons is oxygen, whether it has 8 or 18 neutrons.
Standard definition by IUPAC · Atomic number
Atomic weight
The average weight of an element’s atoms, weighted by how abundant each isotope is in nature, in atomic mass units. For 14 elements CIAAW publishes a range instead of a single value, because that abundance varies a little from sample to sample.
Standard definition by CIAAW — Commission on Isotopic Abundances and Atomic Weights · Atomic weight
Isotope
Atoms of the same element (same number of protons) with a different number of neutrons, and therefore a different mass. Carbon-12 and carbon-14 are isotopes of carbon; only the second one is radioactive.
s/p/d/f block
A split of the periodic table by the type of orbital receiving the atom’s last electron. Alkali and alkaline-earth metals sit in the s block, most everyday elements in the p block, transition metals in the d block, and lanthanides and actinides in the f block.
Standard definition by IUPAC · s/p/d/f block
Standard uncertainty
The margin attached to a measured value, usually written in parentheses on the last digits. A constant that is "exact by definition" has zero standard uncertainty; a measured one, like the gravitational constant G, always carries some.
Standard definition by BIPM — Bureau International des Poids et Mesures (SI) · Standard uncertainty