How Bitcoin works

Bitcoin is the world's first decentralized digital currency, designed to let people send money directly to each other without banks or governments in the middle. It runs on a public blockchain network, which is also called Bitcoin—a shared record of every transaction that's secured by cryptography and anyone can verify but no single entity or person controls. This article explores how Bitcoin works looking at the technology behind it, how transactions on the network are processed, how new tokens are created through mining, what affects its price, and how to hold it safely.

Disclaimer: This guide is for educational purposes only. It is not financial advice, not a solicitation, and not for UK audiences. Bitcoin and cryptocurrency trading are risky and not suitable for all users.

Key takeaways about how Bitcoin works

• Bitcoin is a decentralized, peer-to-peer digital currency, powered by transactions are verified by a global network of miners using Proof of Work, with no central authority. 

• Bitcoin is both the name of the decentralized blockchain network, and its native currency—the latter is often represented by its ticker, BTC.

• Bitcoin's price is driven by supply and demand, halving cycles, institutional adoption, and macroeconomic conditions—it reached an all-time high of approximately $126,198 in October 2025

• Supply is permanently capped at 21 million coins; halving events cut the mining reward roughly every four years, with the most recent in April 2024 reducing it to 3.125 BTC per block

What is Bitcoin and what is it used for

Bitcoin is a digital currency that works without a central authority. Instead of relying on a bank to process payments, it uses a peer-to-peer network backed by a public ledger (the blockchain) and secured by cryptography. Introduced in 2009 by the pseudonymous Satoshi Nakamoto, it was built to solve a basic problem: how to send value online without needing a middleman.

Bitcoin is both the name of the decentralized network and the currency that operates on it. Unlike later projects such as Ethereum (the network) and ether (the token), Bitcoin uses the same name for both. When written with a capital B, "Bitcoin" typically refers to the network or protocol; lowercase "bitcoin" or the ticker "BTC" refers to the unit of currency. Each bitcoin is divisible down to eight decimal places—the smallest unit, 0.00000001 BTC, is called a satoshi, named after the pseudonymous creator Satoshi Nakamoto.

Bitcoin’s core purposes are borderless payments, reduced dependence on traditional banks, and financial self-reliance. Over time, Bitcoin has also become a relatively scarce digital asset—often referred to as digital gold—because of its fixed supply cap, portability, and resistance to censorship. As of May 26 2026, Bitcoin remains the largest cryptocurrency by market capitalization, according to MetaMask.

Institutional interest has grown significantly since the approval of US spot Bitcoin ETFs in January 2024. US spot Bitcoin ETFs collectively held over $106 billion in assets under management as of May 2026.

The Bitcoin blockchain explained

Bitcoin’s blockchain network is the underlying technology that makes the token possible. It works like a shared public record book: every transaction ever made is grouped into blocks, and each block is linked to the one before it using a cryptographic fingerprint called a hash. This creates a chain of blocks—a blockchain—that records the full history and can't be altered without redoing the work for every block that follows.

Bitcoin uses a system of paired cryptographic keys to manage ownership. A Public Key works like a bank account or email address—anyone can send funds to it. The matching Private Key is what authorizes spending from that address. Only the person holding the Private Key can move those funds. The Secret Recovery Phrase—a 12- or 24-word backup that can restore a wallet if access is lost—should be kept offline and never shared.

The result is a system where anyone can check that transactions are valid, but no single entity is in charge.

How Bitcoin tracks ownership: the UTXO model

Most digital systems track balances the way a bank does—one account, one running total. Bitcoin works differently. It uses an unspent transaction output (UTXO) model, which tracks individual pieces of Bitcoin received in past transactions rather than maintaining a single balance.

When Bitcoin is spent, it works like paying with cash: the wallet selects one or more UTXOs as inputs, sends the right amount to the recipient, and returns any leftover "change" to a new address the sender controls. Each UTXO can only be spent once, which makes verification straightforward and strengthens privacy by encouraging the use of fresh addresses.

How Bitcoin transactions work

A Bitcoin transaction is a transfer of value from one address to another. Each transaction contains the sender's and recipient's addresses, the amount, and a digital signature created with the sender's Private Key.

The process works in a few steps. The sender creates a transaction and signs it with their Private Key. That transaction is broadcast to the Bitcoin network, where miners check that it's valid and include it in a block. Once the block is confirmed on the blockchain, the transaction is permanent and irreversible.

Bitcoin transactions are pseudonymous—addresses don't reveal personal identity—but all activity is publicly visible on the blockchain. Network fees, denominated in satoshis (the smallest Bitcoin unit, equal to one hundred-millionth of a BTC), are paid to miners to prioritize and process transactions.

A new block is mined roughly every ten minutes. Most recipients consider a transaction fully settled after six confirmations (about one hour), though congestion or low fees can slow things down.

Bitcoin mining and Proof of Work

Mining is how the Bitcoin network stays secure and decentralized. It uses a system called Proof of Work (PoW): miners compete to solve a computational puzzle, and the first one to find a valid answer gets to add the next block of transactions to the blockchain.

In practice, miners take the data from a block and run it through a cryptographic function (SHA-256) over and over, each time with a slightly different input number (called a nonce), trying to produce a result that meets the network's difficulty target. This takes enormous computing power, which is the point. The cost of mining is what makes it impractical for anyone to tamper with the ledger.

Miners earn two things for their work: newly created bitcoins (the block reward) and the network fees from the transactions they include. To keep the pace of new blocks steady, the network adjusts the puzzle difficulty approximately every 2,016 blocks (roughly two weeks), targeting one new block every ten minutes.

Energy consumption

Mining requires significant electricity. The Cambridge Centre for Alternative Finance's 2025 Digital Mining Industry Report estimated annual consumption at approximately 138 TWh, with emissions of roughly 39.8 MtCO₂e. The same report found that 52.4% of mining energy now comes from sustainable sources, including renewables and nuclear. For context, 138 TWh is comparable to the annual electricity use of a mid-sized country.

Bitcoin supply, rewards, and halving events

Bitcoin has a hard cap of 21 million coins—no more will ever be created. Each bitcoin is divisible into 100 million smaller units called satoshis, so small transactions are still practical even as the price per coin rises.

A built-in event called a "halving" cuts the block reward in half approximately every 210,000 blocks (roughly every four years). This gradually slows the rate at which new bitcoins enter circulation, creating a predictable, disinflationary supply schedule.

The most recent halving occurred on April 19, 2024, at block 840,000, reducing the reward from 6.25 BTC to 3.125 BTC. Historically, halvings have coincided with increased market attention—though past patterns don't guarantee future outcomes.

Bitcoin security, decentralization, and trade-offs

Bitcoin's security comes from three things: Proof of Work, cryptography, and decentralization. Every node on the network independently checks transactions and blocks against the protocol rules. To tamper with the blockchain, an attacker would need to control more than half of the network's total computing power—a scenario that's economically impractical.

That said, this design involves trade-offs:

• Speed: the base layer processes only a few transactions per second, much slower than centralized payment systems; layer-2 protocols like the Lightning Network are being developed to handle payments off-chain and improve speed

• Energy: mining is power-intensive, though the share of sustainable energy is growing

• Regulation: rules differ by country and can affect access and liquidity

• Governance: protocol changes require broad consensus, which slows upgrades

• Privacy: addresses are pseudonymous, not anonymous, and blockchain analytics can sometimes link transactions to individuals; quantum computing could pose long-term cryptographic risks, though current hardware is far from capable of breaking Bitcoin's encryption

Despite these, Bitcoin's transparent, auditable ledger and global consensus mechanism make it one of the most resilient digital systems in operation.

What drives Bitcoin's price

Bitcoin's price is set by open-market supply and demand. It isn't backed by a government or physical commodity, which contributes to its volatility—price swings are driven by perception, adoption, macroeconomic conditions, regulation, and technological developments.

Bitcoin reached an all-time high of approximately $126,080 in October 2025, according to MetaMask. It then fell roughly 30% within weeks—consistent with the sharp drawdowns seen in every prior cycle. For comparison, the 2021 cycle saw Bitcoin rise from around $10,000 in mid-2020 to nearly $69,000 in November 2021 before declining more than 75% to about $16,000 by late 2022. For a detailed comparison of holding spot Bitcoin vs trading perpetual futures, see perpetual futures vs spot Bitcoin.

Core price drivers include monetary policy and interest rate expectations, institutional adoption (accelerated by the approval of US spot Bitcoin ETFs in January 2024), technological upgrades, and halving cycles that reduce new supply. Bitcoin's volatility reflects both its opportunity and its risk.

Self-custody vs brokers: how to hold Bitcoin

Bitcoin can be held two ways: in a self-custodial wallet, where the holder controls their own Private Keys, or through a broker or exchange, which holds coins on the holder's behalf. The choice affects control, security, and tax reporting.

MetaMask provides a self-custodial wallet that supports Bitcoin natively, keeping Private Keys with the wallet holder rather than a third party. This aligns with Bitcoin's original design—but it also means the holder is fully responsible for securing their Private Keys and complying with applicable tax laws. With self-custody, the holder must also maintain their own transaction records, since no broker generates tax forms on their behalf.

In most jurisdictions, selling, trading, or swapping Bitcoin triggers a taxable event, typically categorized as a capital gain or loss. Brokers usually report transactions to tax authorities, but peer-to-peer trades must also be declared where applicable. For US-specific guidance, including 1099-DA requirements, see the MetaMask guide to US crypto tax reporting in 2026.

Bitcoin can also be purchased directly through a self-custodial wallet. For a step-by-step guide—including options for cards, bank transfers, and Apple Pay—see how to buy Bitcoin on MetaMask.

Key Bitcoin terms

How Bitcoin works: summary

Bitcoin is a decentralized digital currency that operates on a public blockchain without a central authority. It uses the UTXO model to track ownership, where each transaction consumes unspent outputs and creates new ones rather than updating an account balance. New bitcoins are created through Proof of Work mining, where miners compete to solve cryptographic puzzles and earn block rewards. Bitcoin's total supply is capped at 21 million coins, and halving events reduce the mining reward approximately every four years—the most recent halving in April 2024 cut the reward to 3.125 BTC per block. Bitcoin can be held through self-custodial wallets like MetaMask, where the holder controls their own private keys, or through brokers and exchanges that hold funds on the holder's behalf. Both methods carry tax reporting obligations in most jurisdictions.