Each rod is worth ten of the rod before it. After the hundreds, each name covers three rods: one, ten and a hundred of it. The last two names, duotrigintillion and googol, have one rod each.
From billion on, a name starts with a counting word, mostly from Latin. Multiply what it stands for by 3 and add 3 to get its zeros. Octillion starts with oct, which stands for 8: 3 × 8 + 3 = 27 zeros. An octopus has eight arms; its name means “eight feet” in Greek.
These are the names used in the United States and in British English today. In older British English, and in much of Europe today, a billion means a million million, and a thousand million is a milliard.
The names past a vigintillion follow the same pattern, but they are rarely used, and most of them are not in dictionaries.
A googolplex
A googolplex is a 1 with a googol zeros. The boy who named the googol, Milton Sirotta, suggested this name too, and his uncle, Edward Kasner, settled what it means.
No one could ever count that far. Googols add: 10 googols is only a 1 with 101 zeros. A googolplex would take 10a googol − 100 googols, and that number has nearly a googol zeros of its own.
It will not fit, either. Written out, it is a 1 and 10100 zeros. A rough estimate of the atoms in the universe we can see is about 1080, so one digit on every atom would come nowhere near.
🧮 The abacus
Each rod holds ten beads. Tap the abacus and one bead slides up. When a rod has all ten,
they slide back and one bead slides up on the next rod: ten ones make one ten, ten tens make one hundred, and so on.
🏷️ The names
Under each rod is its place: ones, tens, hundreds, thousands, all the way to a googol.
The number is written above the abacus, and in words under it. The thin line under the words fills as you reach new rods: all 101 rods, full, is a googol.
🌌 The googol abacus
Tap the number while you play, and scroll down: your googol abacus counts every googol you have counted, and a new abacus does not start it again. Googols add: each abacus adds the most googols its top rod held, 1 to 9. Each rod it reaches doubles what an 📈 Invest star gives: 2% at 1 googol, 4% at 10, 8% at 100.
⚙️ The machines
Buy counting machines in the order people made them, from a Greek counting board to the fastest computers of our own time.
Each one counts by itself. The price comes off your abacus, so you can watch it borrow: one hundred becomes ten tens.
Tap a machine's name to read about it.
⭐ Stars and upgrades
Every new rod you reach gives you a star. Past a googol, each googol more on the top rod gives one star more than the last: 2, then 3, up to 9. Under each machine are its five upgrades: tap the next one to buy it.
At 10, 25 and 50 of a machine it can count twice as fast, for 1, 2 and 4 stars; at 100, up to 10 times as fast
(the older the machine, the more), for 8 stars; at 200, every machine faster, 2% for each star it costs (its place
in the list: 1 for the counting board). You can't buy every upgrade on one abacus: pick the ones that help most.
Once you have a machine on this abacus, buy a star any time, for an upgrade or for 🧰: it costs about 5 minutes of counting, its price holds until you buy it, so what you save toward is what you pay; each star after it on this abacus costs a little more.
🧰 Abacus upgrades
Tap 🧰 by your stars to spend stars on upgrades for every abacus to come: 🎁 Star box (1 star buys 16 stars, one time only), ⏰ Longer away, 🔁 Re-buy, 🛒 Helper, 🆕 Auto-buy, 👆 Auto-tap, ♻️ Auto new abacus, 💤 Works while away
and 📈 Invest. Stars spent here are not given back at a new abacus: they stay spent, and the upgrades stay.
🏆 A new abacus
Reach a googol and you can start a new abacus, or count on: each googol more on the top rod, up to 9, counts on your
googol abacus too, and stays counted. Your count, machines and
upgrades start again, but every star comes back to spend again, and every machine counts 10% faster for each new
abacus you have started. Buy every upgrade there is and you have done it all. Your 📒 Firsts are kept. It takes two taps, and can be undone for 10 seconds.
🌙 Time
Your machines keep counting while the game is closed, up to 8 hours (more with ⏰ Longer away in 🧰). Coming back after a week gives what one night gives, so there is no hurry. With 💤 Works while away in 🧰, the upgrades you own and have on run then too, and the card says what they did; it is never better than playing.
🏆 The top
A googol is a one with a hundred zeros. Reach it and the top rod gets its first bead.
📱 Keep screen on
Stops the screen turning off while the game is open. It uses more battery.
🔄 Start over
Clears your count, your machines and your firsts on this device.