How many blades of grass are there in the world?
No one has estimated this seriously, so what follows is arithmetic with honest error bars of a factor of ten. Grassland covers roughly 40 million square kilometres, about a quarter of the land surface. A dense managed lawn carries on the order of 50,000 to 100,000 blades per square metre; wild steppe and savanna are far sparser, perhaps a few thousand. Take 50,000 per square metre as a generous average and you land near 2 × 10^18.
How the figure is arrived at
Count blades in a small measured quadrat — a 10 cm square is enough — scale to a square metre, then multiply by global grassland area. The whole answer hinges on the density figure, and lawn density is five to twenty times natural grassland density, so quoting a lawn number as a global average inflates the result by an order of magnitude.
How confident it is
- Low estimate
- 200,000,000,000,000,000
- High estimate
- 20,000,000,000,000,000,000
- Spread
- 100.0× between the bounds
Presented as a worked estimate rather than a finding. Anyone quoting a precise figure for this has multiplied two guesses together and rounded the result badly.
Other living things and the natural world counts
- How many people are there in the world? about 8.2 billion
- How many grains of sand are there on Earth? roughly 7.5 quintillion on the world's beaches
- How many ants are there in the world? about 20 quadrillion
- How many trees are there in the world? about 3 trillion
- How many insects are there? about 10 quintillion
- How many species are there? about 8.7 million
- How many people have ever lived? about 117 billion
- How many drops of water are there in the ocean? about 27 septillion
- How many fish are there in the sea? somewhere between 3 trillion and 100 trillion — nobody knows
- How many species are endangered? more than 45,000 assessed as threatened
- How many bees are there in the world? roughly 2 trillion managed honey bees
- How many birds are there in the world? about 50 billion wild birds
- How many bacteria are there on Earth? about 5 nonillion
- How many earthquakes are there each year? about 20,000 located a year — around 55 a day
Common questions
- How many blades of grass are there in the world?
- very roughly 2 quintillion
- How is that estimated?
- Count blades in a small measured quadrat — a 10 cm square is enough — scale to a square metre, then multiply by global grassland area. The whole answer hinges on the density figure, and lawn density is five to twenty times natural grassland density, so quoting a lawn number as a global average inflates the result by an order of magnitude.
Related pages
- How many people are there in the world? about 8.2 billion
- How many grains of sand are there on Earth? roughly 7.5 quintillion on the world's beaches
- How many ants are there in the world? about 20 quadrillion
- How many trees are there in the world? about 3 trillion
- How many insects are there? about 10 quintillion
- How many species are there? about 8.7 million
- How many people have ever lived? about 117 billion
- How many drops of water are there in the ocean? about 27 septillion
- How many stars are there in the universe? Space and the universe
- How many countries are there in the world? Things people built
- How many bones are in the human body? The human body
- How many stars are there in the Milky Way? Space and the universe
- How many atoms are there in the universe? Space and the universe
- How many galaxies are there? Space and the universe
Sources
- Calculated on this page — At One Place