Guess the number 1 to 100
A secret number between 1 and 100. Can you find it in 7 guesses?
Your name, guesses and time go on today's public board.
How it works
Guess a number between 1 and 100
The game picks a secret whole number from 1 to 100. Type a guess and the game answers bigger or smaller. Keep going until you hit it. The bar under the clue shows which numbers are still possible, so you never lose track.
Strategy
Why 7 guesses is always enough
Guess the middle and every answer cuts the possible numbers in half: 100 become 50, then 25, 13, 7, 4, 2 and finally 1. That is 7 guesses at most, because 2 to the power of 7 is 128, the first power of two above 100. Here is a real game where the secret number is 73:
| Guess | Answer | Still possible |
|---|---|---|
| 50 | ↑ Bigger | 51 to 100 |
| 75 | ↓ Smaller | 51 to 74 |
| 62 | ↑ Bigger | 63 to 74 |
| 68 | ↑ Bigger | 69 to 74 |
| 71 | ↑ Bigger | 72 to 74 |
| 73 | Correct | Found in 6 guesses |
- Start with 50. It splits the range into two equal halves.
- If the answer is bigger, go to 75. If it is smaller, go to 25.
- Always pick the middle of what is left. Rounding down is fine.
- A guess outside the bar is a wasted guess, so keep an eye on it.
Next step
Ready for more?
Got it down? Try 1 to 1,000, where perfect play needs 10 guesses, or the Daily Challenge, where everyone gets the same number.
More ways to play
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FAQ
Questions
What is the best first guess for 1 to 100?
50. It splits the range into two equal halves, so whatever the answer is, you remove about half of the numbers.
How many guesses do you need to guess a number from 1 to 100?
At most 7 with perfect play. Lucky guesses can make it fewer, but 7 is the guaranteed limit.
Can I play guess the number 1 to 100 with a friend?
Yes. Use Duo mode: one player hides a number and the other guesses it, then you swap.
Is it free?
Yes. It is free, with no download, no signup and no ads.