How Many Insects Are on Earth? Smithsonian Population Estimate

Where the 10 Quintillion Figure Originates

The 10 quintillion figure comes from a single information sheet prepared by the Smithsonian’s National Museum of Natural History. According to that documentation, insects hold the largest biomass of any terrestrial animals on Earth. Researchers point out that the figure is an estimate that long predates modern global surveys capable of testing such a grand scale. Scientists advise reading the total as “somewhere in the ballpark of ten billion billion” rather than an exact count, as nobody has ever surveyed every patch of dirt and forest canopy directly.

Why Counting Insects Remains Almost Impossible

Generating a global insect count requires scientists to sample small plots, measure what lives there, and scale those numbers across various habitat types. According to a June 2026 study published on insect species diversity, the total number of insect species is now estimated between 14 million and 30 million, which is more than triple the long-standing working figure of six million. Brian Fisher, an entomologist at the California Academy of Sciences who was not part of that study, noted that the new species estimate serves as a lower floor rather than a ceiling. “Even though it’s a crazy large number, I believe their approach gives us the lower bounds of what insect diversity is in the world,” he stated regarding the ongoing difficulty of pinning down exact totals.

Subterranean Ecosystems and Hidden Biomass

Most of the planet’s insect life remains entirely invisible to casual observers, existing primarily underground and in dense leaf litter. A 2023 synthesis published in Science Advances from Ron Milo’s lab, which drew on data from roughly 500 sites, estimated about 1 x 10^19 soil arthropods on Earth. Approximately 95% of those subterranean creatures are mites and springtails. Additionally, a 2022 study published in PNAS that integrated data from every continent estimated the global ant population at roughly 20 quadrillion, with a combined mass that surpasses all wild birds and mammals combined.

Declining Trends Despite Massive Abundance

A massive global total does not mean insect populations are stable or immune to environmental pressures. A 2020 meta-analysis published in Science, which compiled long-term surveys across 1,676 sites, found land-dwelling insects declining at just under 1% a year—amounting to a drop of more than a quarter over three decades. A broader assessment by dozens of scientists placed typical reported declines between 1% and 2% annually, though rates varied significantly by region and freshwater insects actually showed increases. Reacting to those findings, Michigan State University researcher Nick Haddad, who was not involved in the study, called the pattern “jaw dropping” and warned that continued “decline on land at this rate will be catastrophic for ecological systems and for humans.”

Frequently Asked Questions