Researchers do not agree on the number of living species. Before seeing their figures, make your own estimate.
The question
How many species live on Earth?
What you do First place your own estimate on the scale. Then compare it with what has actually been recorded, and with the researchers’ estimates.
Without JavaScript, here are the animation’s data.
| Database | Species listed | Source |
|---|---|---|
| Catalogue of Life (2026) | about 2.5 million | 1 |
| Who | Estimate | Source |
|---|---|---|
| Costello et al., 2012 | 1.8 to 2.0 million | 2 |
| Specialists, before 2011 | 3 to 100 million | 3 |
| Mora et al., 2011 | 8.7 million, give or take 1.3 million | 4 |
| Chapman, 2009 | about 11 million | 5 |
| Larsen et al., 2017 (micro-organisms included) | 1 to 6 billion | 6 |
| Species | Not yet described | Source |
|---|---|---|
| All | 86% | 7 |
| In the ocean | 91% | 7 |
The scale is logarithmic: each mark is ten times the one before. The recorded figure is the sum of the Catalogue of Life’s four counters (animals, plants, fungi, other kingdoms). Mora et al.’s range (7.4 to 10 million) is calculated from 8.7 ± 1.3; their estimate covers eukaryotes.
The takeaway About two and a half million species have been recorded. Estimates of the total range from about two million to billions: no figure commands agreement. Here, “we don’t know” is a scientific answer.
Sources 7
Catalogue of Life, version COL26.10 XR, 16 October 2026, home page, per-kingdom counters (Animalia, Plantae, Fungi, other kingdoms; total 2,458,683), active version “COL26.10 XR” released on 16 October 2026; accessed on 24 October 2026.
1.800.193 species in COL […] 408.109 species in COL […] 174.658 species in COL […] 75.723 species in COL
Open access open the source · checked on 25 October 2026
Costello, Mark J., Wilson, Simon P. and Houlding, Brett, “Predicting Total Global Species Richness Using Rates of Species Description and Estimates of Taxonomic Effort”, Systematic Biology, vol. 61, no. 5, 2012, p. 871-883, abstract.
We predict that there may be 1.8–2.0 million species on Earth, of which about 0.3 million are marine, significantly less than some previous estimates.
Open access open the source · checked on 9 September 2026
Mora, Camilo, Tittensor, Derek P., Adl, Sina, Simpson, Alastair G. B. and Worm, Boris, “How Many Species Are There on Earth and in the Ocean?”, PLoS Biology, vol. 9, no. 8, e1001127, 2011, introduction.
Globally, our best approximation to the total number of species is based on the opinion of taxonomic experts, whose estimates range between 3 and 100 million species
Open access open the source · checked on 9 September 2026
Mora, Camilo, Tittensor, Derek P., Adl, Sina, Simpson, Alastair G. B. and Worm, Boris, “How Many Species Are There on Earth and in the Ocean?”, PLoS Biology, vol. 9, no. 8, e1001127, 2011, abstract.
it predicts ~8.7 million (±1.3 million SE) eukaryotic species globally, of which ~2.2 million (±0.18 million SE) are marine
Open access open the source · checked on 9 September 2026
Chapman, Arthur D., Numbers of Living Species in Australia and the World, Australian Biological Resources Study, 2009, Introduction, p. 2.
In this report figures of close to 11 million species worldwide and about 570.000 for Australia are accepted.
Open access · checked on 24 October 2026
Larsen, Brendan B. et al., “Inordinate Fondness Multiplied and Redistributed: The Number of Species on Earth and the New Pie of Life”, The Quarterly Review of Biology, vol. 92, 2017, p. 229-265, abstract.
Our estimates suggest that there are likely to be at least 1 to 6 billion species on Earth. Furthermore, in contrast to previous estimates, the new Pie of Life is dominated by bacteria (approximately 70–90% of species) and insects are only one of many hyperdiverse groups.
Paywalled · checked on 25 October 2026
Mora, Camilo, Tittensor, Derek P., Adl, Sina, Simpson, Alastair G. B. and Worm, Boris, “How Many Species Are There on Earth and in the Ocean?”, PLoS Biology, vol. 9, no. 8, e1001127, 2011, abstract.
our results suggest that some 86% of existing species on Earth and 91% of species in the ocean still await description
Open access open the source · checked on 9 September 2026
Read the entry 5.1 · The classification and evolution of animals