Nonce table: watch a search for four zeros, one try at a time
Type a line. This page puts it in a block next to a counter called the nonce, then works out the block's hash, a 64-digit fingerprint. If the hash does not start with four zeros, the page adds one to the nonce and tries again. The table shows the tries.
Idle. Nothing is running.
- Tries so far
- 0
- The table is showing
- nothing yet
- Every try is hashed and counted, shown or not.
| Nonce | Hash of the block with that nonce | Zeros |
|---|---|---|
| Closest so far | ||
| · | · | |
| No zeros | 0 | · | |
| 1 zero | 0 | · | |
| 2 zeros | 0 | · | |
| 3 zeros | 0 | · | |
| 4 or more: found | 0 | · |
Every row is a hash this page really worked out for that nonce, at the moment the row appears. Once the search speeds up there are far more tries than rows, so the table shows the latest try each time it adds a row. The counter and the tally count every one. The bars are drawn to scale.
Your line stays in your browser; nothing is uploaded. Each run builds the block again with the current time, so the search and its winning nonce are different every time.
Four zeros is the easy end
Every extra zero makes the search 16 times longer. The blocks this site strikes go to 8, 10, 11 or 12 zeros, on a chip that does about 137 billion tries a second.
Run the search at the top of this page. This window then fills in with the number of tries it took and the speed measured in your browser.
This search took before a hash began with four zeros. The average is 65,536 tries; any one search can be much shorter or much longer.
Flat out, this page hashes about in your browser (measured just now: , on one CPU thread). At that speed your search is about of work.
The chip that strikes this site's blocks does about 137 billion tries a second. It would get through your whole search in about .
Now add zeros. 8 zeros needs about 4.3 billion tries, 10 about 1.1 trillion, 11 about 17.6 trillion and 12 about 281 trillion.
At this browser's measured rate, a 12-zero block would take about on average. The chip takes about 34 minutes.
| Leading zeros | Tries on average | The chip, at 137 GH/s | This page in your browser |
|---|---|---|---|
| 4 zeros the search above | 65,536 | 478 nanoseconds | not measured yet |
| 8 zeros | 4.29 billion | 31.4 milliseconds | not measured yet |
| 10 zeros | 1.1 trillion | 8.03 seconds | not measured yet |
| 11 zeros | 17.6 trillion | 2.14 minutes | not measured yet |
| 12 zeros | 281 trillion | 34.2 minutes | not measured yet |
137 GH/s is the sustained rate measured on this site's miner, a GekkoScience Compac F (one BM1397 chip), on 9 November 2026. Every time in the table is an average worked out from a rate, not a race; any single search can be much shorter or longer. Try other rates in the leading zeros calculator.
What you just watched
The page built a small block around your line. The line went into a coinbase transaction, that transaction was hashed into a merkle root, and the merkle root went into an 80-byte Bitcoin-format block header along with the time and a 4-byte counter, the nonce. Each try sets the nonce to the next number, runs SHA-256 twice over those 80 bytes, and reads the result as a 64-digit number in hexadecimal. That number is the hash. Change the nonce by one and every digit of the hash changes, with no pattern to follow. When the search ends you can open the winning header in the block header calculator and check it yourself.
Why most tries fail
Each digit of a hash is one of 16 values, 0 to 9 and a to f, and each one is as good as random. About 1 try in 16 gives a hash that starts with a zero. Two zeros turn up in 1 try in 256, three in 1 in 4,096, and four in 1 in 65,536. The tally under the table counts exactly this, which is why its first row holds nearly every try. A failed try tells you nothing about where the winning nonce is, so there is no shortcut. The only method is the one in the table: try the next number.
How the table keeps up
Every row is a hash this page really worked out for that nonce, at the moment the row appears. Nothing is made up, worked out ahead of time, or replayed. Your browser could finish this search in a second or two, so the page holds it back to give you something to watch. The first six tries arrive one at a time. Then the pace climbs to about 6,400 tries a second, and the table can only show about 1 try in every 1,024: the latest one, each time it adds a row. The counter and the tally still count every single try. The pinned row is the try with the most leading zeros so far, and an orange tile only ever sits under a zero that is really at the start of a hash.
The search pauses while the table is off screen or the tab is hidden. If your device asks for reduced motion, the page runs the search without animating it, then shows the result and a fixed sample of the rows.
How the speed is measured
After the find, the page hashes the same block flat out for about a third of a second, with nothing drawn, and counts how many hashes it got through. That is the rate used in the sentences and the table: this page's plain JavaScript on one CPU thread. The browser vs ASIC race runs a tighter loop in a background worker and reports a higher rate for the same machine. To turn any rate into a time for any number of zeros, use the leading zeros calculator. The four depths a real chip strikes, and what each one costs in work, are on the depth ladder.
More tools
Block header calculator
Decode 80 bytes, double SHA-256 them, and check the hash against the target.
Leading zeros calculator
How long N leading zeros takes at any hash rate, with the odds.
Genesis block decoder
Bitcoin's block 0 byte by byte, with the Times headline in its coinbase.
Browser vs ASIC
Measure your browser's real hash rate and set it against a mining chip.
Have a real chip strike your own line, from $6.99. One sentence of yours, mined into a block by a Bitcoin ASIC. Not on Bitcoin's blockchain; the proof of work is real.