Glossary · Crypto
Blockchain
A blockchain is a shared record of transactions kept in blocks that are chained together, so that changing an old entry would break every block after it.
Also called: distributed ledger, block chain, chain of blocks, DLT
The number of the latest block on November 11, 2026; about 143 new blocks a day over the last year.
In plain words
Imagine a class notebook where each lesson’s attendance goes on a new page, and at the bottom of every page you copy a short code made from everything on the page before. If someone secretly changed an old page, its code would no longer match, and neither would the code on any later page. That chained notebook is the idea behind a blockchain.
In a cryptocurrency, each page is a block: a batch of transactions, a timestamp and the fingerprint (the hash) of the block before it. Thousands of computers keep a full copy of the chain and check every new block against the rules before adding it.
Bitcoin’s chain began on January 3, 2009. It had reached block number 975,498 by November 11, 2026, adding one about every 10.1 minutes.
Example
Why you cannot quietly edit block 100
A hash is a short code computed from data; change a single character of the data and the code changes completely.
- Block 100 holds a payment of 1 BTC to Alice. Its fingerprint begins 7f3a…, and block 101 stores 7f3a… as “previous block”.
- A cheat changes the payment so the 1 BTC goes to himself. Block 100’s fingerprint becomes c91e…, and block 101 no longer points to it.
- To hide the change he must redo block 101, then 102, and every block since, each one a fresh proof of work puzzle, while the honest network keeps adding new blocks.
- On bitcoin that means out-running the rest of the network’s computers, which make about 1.0 sextillion guesses a second.
That is why a payment buried under six blocks, about an hour, is treated as final.
One level deeper
A blockchain is a kind of distributed ledger: no master copy, many equal ones. The hard part is agreement. When two computers hear about two different new blocks, which one counts? Each blockchain has a consensus rule: bitcoin follows the chain with the most work behind it, and Ethereum uses proof of stake.
The design trades speed for trust. Bitcoin adds a block of a few thousand payments about every 10 minutes, a handful of transactions a second, while a card network handles thousands a second. Faster systems are built on top of it, and other blockchains choose different trade-offs.
Public blockchains, like bitcoin’s, let anyone read the record and join; private (permissioned) ones are run by a group of companies, such as banks settling trades. Either way, the record keeps what it was given: a mistaken payment stays in it.
Bitcoin’s blocks a day since 2009
The network aims at one block every 10 minutes, 144 a day, but it cannot set the pace directly. Every 2,016 blocks (about two weeks) it makes the puzzle harder or easier, so the pace drifts back to the target. In 2010, when computing power poured in faster than the puzzle could adjust, blocks came far faster. Over the last year they averaged 143 a day.
The numbers behind the chart
| Date | Blocks a day |
|---|---|
| Jan 2009 | 88 |
| Dec 2010 | 181 |
| Dec 2020 | 146 |
| Dec 2022 | 142 |
| Dec 2023 | 148 |
| Dec 2024 | 147 |
| Dec 2025 | 142 |
| Nov 2026 | 132 |
Why it matters
It lets strangers share one record of who owns what without trusting a single keeper. Every cryptocurrency is built on one.
It makes history hard to rewrite: the older a block, the more work it would take to change it.
The idea spread beyond money, to supply chains, land records and the settling of trades, though in many of those uses an ordinary shared database does the job more cheaply.
A common mistake
Myth: If something is recorded on a blockchain, it must be true.
In fact: A blockchain only guarantees that an entry has not been changed since it was added. If someone records a false claim (a fake certificate, a wrong delivery date), the blockchain keeps the false claim just as faithfully.
Questions people ask
Is blockchain the same as bitcoin?
No. Bitcoin is one cryptocurrency, and it runs on its own blockchain, the first one. Ethereum and thousands of other coins have their own, and some blockchains have no coin at all.
Who owns a blockchain?
A public one belongs to no one: anyone can download the software, keep a copy and check every rule. A private blockchain belongs to the companies that run it.
How long is the bitcoin blockchain?
The chain had reached block number 975,498 on November 11, 2026, counting from block 0, the genesis block of January 3, 2009.
Read more on BigCapital
About the numbers
- The numbers on this page are recalculated from the data every night; the sources are listed at the end of the page.
- Bitcoin blocks per day: Coin Metrics Community Network Data, metric BlkCnt. License: CC BY-NC 4.0.
- Bitcoin hash rate: Coin Metrics Community Network Data, metric HashRate. License: CC BY-NC 4.0.
- Block counts are by UTC day; Coin Metrics counts a block mined in the first minutes of a day on the day before.
- Crypto data: Coin Metrics Community Network Data, used under the CC BY-NC 4.0 license.
- This page explains a term. It is not investment advice.