Free tools · Mining time
Leading zeros calculator: how long to mine N zeros
Pick a hash rate and a number of leading hex zeros. This page works out how many hashes the search takes on average, how long that is, and your odds of finishing within a time you choose.
The search
Presets fill in the hash rate. Every figure below is arithmetic on the two numbers you set.
Reference: one 137 GH/s chip
137 GH/s is the sustained rate measured on this site's miner, a GekkoScience Compac F (one BM1397 chip), on 9 November 2026. Times are averages computed from that rate; any single search can be much shorter or longer.
| Leading zeros | Expected hashes | Average time | Median time |
|---|---|---|---|
| 8 zeros · Genesis · $6.99 | 4.29 billion | 31.4 milliseconds | 21.7 milliseconds |
| 9 zeros | 68.7 billion | 502 milliseconds | 348 milliseconds |
| 10 zeros · Gold · $9.99 | 1.1 trillion | 8.03 seconds | 5.56 seconds |
| 11 zeros · Platinum · $29 | 17.6 trillion | 2.14 minutes | 1.48 minutes |
| 12 zeros · Prismatic · $99 | 281 trillion | 34.2 minutes | 23.7 minutes |
| 13 zeros | 4.5 quadrillion | 9.13 hours | 6.33 hours |
| 14 zeros | 72.1 quadrillion | 6.09 days | 4.22 days |
| 15 zeros | 1.15 quintillion | 97.4 days | 67.5 days |
8, 10, 11 and 12 zeros are the four depths Strike a Block sells. The rows past 12 are here for scale; they are not for sale.
How the numbers are worked out
A SHA-256 hash, written in hex, is 64 characters, each one of 16 values. For a well-behaved hash function every character is as good as random, so the chance that a hash starts with N zeros is 1 in 16N. On average you need 16N attempts to find one. Divide by your hash rate and you have the average time. Every extra zero multiplies the work by 16.
The average hides a wide spread. The median is ln 2 times the average, about 69% of it, so half of all searches finish early. About 63% finish within the average time, and about 5% take more than three times as long. The chance of finishing within a time t is 1 − e−t ÷ average, which is what the last tile shows.
Why there is no shortcut
Each hash is an independent lottery ticket. Nothing about a failed attempt tells you where the winning nonce is, and SHA-256 has no known structure that lets you aim for zeros. Being an hour into a search does not make the next hour any luckier: the odds are the same on every single hash. The only way to finish sooner is to buy more tickets per second, which is exactly what a mining chip is for.
Leading zeros and Bitcoin difficulty
Bitcoin's actual rule is that a block's hash, read as a 256-bit number, must be at or below a target. Leading zeros are the visible result. Bitcoin's first target, difficulty 1, required 8 leading hex zeros, which is about 4.3 billion hashes on average. The network re-tunes the target every 2,016 blocks so that blocks keep arriving roughly ten minutes apart no matter how much hardware joins, and today's blocks show about 19 to 20 leading hex zeros. Counting zeros is a coarse ruler, since a target can sit anywhere between two powers of 16, but it is the part you can see with your own eyes.
You can check a real header against its target with the block header calculator, or measure your own browser's hash rate in the browser vs ASIC race and bring the number back here.
More tools
Have a real chip strike your own line, from $6.99. One sentence of yours, mined into a standalone block by a Bitcoin ASIC. Not on Bitcoin's blockchain; the proof of work is real.