How many books have ever been published?
Google engineers set out to answer this in 2010 because they needed to know how much work scanning them all would be, and arrived at 129,864,880. The number of new titles published annually is now roughly 2 to 4 million worldwide including self-published works, so the running total has grown substantially since. The genuinely difficult part is not counting but defining: a hardback, its paperback, its translation and its second edition may be one book or four.
How the figure is arrived at
Google merged about a billion catalogue records from library systems worldwide, then clustered them: records sharing enough metadata were treated as the same work, and the count of clusters was the answer. Most of the engineering was in the clustering rules, because library records are inconsistent, misspelled and multilingual, and the deduplication decisions move the answer by tens of millions.
How confident it is
- Low estimate
- 130,000,000
- High estimate
- 250,000,000
- Spread
- 1.9× between the bounds
Other things people built counts
- How many countries are there in the world? 195 — or 193, or 206, or 249, depending on who is counting
- How many cars are there in the world? about 1.5 billion motor vehicles
- How many planes are in the air right now? roughly 10,000 to 20,000 at any moment
- How many languages are there in the world? about 7,150 living languages
- How many McDonald's are there? about 43,000 in over 100 countries
- How many phones are there in the world? about 8.9 billion mobile connections — more than there are people
- How many nuclear weapons are there? about 12,200 warheads
- How many websites are there? about 1.1 billion hostnames — but only around 200 million active
- How many airports are there in the world? about 45,000 with runways — but only around 4,000 with scheduled airline service
- How many ATMs are there in the world? about 3 million
- How many cities are there in the world? about 10,000 with over 50,000 people; 33 megacities over 10 million
- How many buildings are there in the world? somewhere between 1.5 and 4 billion
- How many computers are there in the world? roughly 2 billion personal computers in use
- How many miles of road are there in the world? about 64 million km — roughly 40 million miles
Common questions
- How many books have ever been published?
- about 130 million as of 2010 — probably over 200 million now
- How is that estimated?
- Google merged about a billion catalogue records from library systems worldwide, then clustered them: records sharing enough metadata were treated as the same work, and the count of clusters was the answer. Most of the engineering was in the clustering rules, because library records are inconsistent, misspelled and multilingual, and the deduplication decisions move the answer by tens of millions.
Related pages
- How many countries are there in the world? 195 — or 193, or 206, or 249, depending on who is counting
- How many cars are there in the world? about 1.5 billion motor vehicles
- How many planes are in the air right now? roughly 10,000 to 20,000 at any moment
- How many languages are there in the world? about 7,150 living languages
- How many McDonald's are there? about 43,000 in over 100 countries
- How many phones are there in the world? about 8.9 billion mobile connections — more than there are people
- How many nuclear weapons are there? about 12,200 warheads
- How many websites are there? about 1.1 billion hostnames — but only around 200 million active
- How many people are there in the world? Living things and the natural world
- How many stars are there in the universe? Space and the universe
- How many bones are in the human body? The human body
- How many grains of sand are there on Earth? Living things and the natural world
- How many ants are there in the world? Living things and the natural world
- How many trees are there in the world? Living things and the natural world
Sources
- Typical range compiled from manufacturer specifications — At One Place