Bitcoin Questions & Answers
Direct, fact-checked answers to the questions people ask most about Bitcoin. Each page includes a quick answer, key takeaways, and a deeper explanation with sources.
How Bitcoin Works
The mechanics, governance, and technology behind the Bitcoin network.
Can Bitcoin Be Shut Down?Bitcoin cannot easily be shut down because it does not operate from one company, server, or country. Thousands of independently operated nodes maintain copies of its blockchain around the world. Individual governments can restrict exchanges or local use, but disabling the entire decentralized network would require stopping participating computers across many jurisdictions simultaneously.Who Controls Bitcoin?No single person, company, or government controls Bitcoin. The network is maintained by thousands of independent node operators worldwide who voluntarily run the same open-source software. Changes to Bitcoin's rules require broad consensus across users, miners, and developers—meaning no one can unilaterally alter the protocol.Why Are There Only 21 Million Bitcoin?Bitcoin has a maximum supply of 21 million coins because its code enforces a schedule that halves the block reward approximately every four years, eventually reducing new issuance to zero. This limit was set by Satoshi Nakamoto in the original code and is enforced by every node on the network. The cap creates absolute digital scarcity, making Bitcoin fundamentally different from fiat currencies that can be printed without limit.What Happens When All Bitcoin Is Mined?When all 21 million Bitcoin are mined—expected around the year 2140—miners will no longer receive new Bitcoin as block rewards. Instead, they will earn income entirely from transaction fees paid by users. The Bitcoin network will continue to function as long as transaction fees provide sufficient incentive for miners to secure the network.Can a Bitcoin Transaction Be Reversed?No. Once a Bitcoin transaction is confirmed on the blockchain, it cannot be reversed, cancelled, or undone by anyone—not the sender, not the receiver, not a bank, and not the network itself. This irreversibility is a fundamental design feature, not a bug. It eliminates chargeback fraud and makes Bitcoin a true bearer instrument, but it also means users must be extremely careful when sending funds.How Long Does a Bitcoin Transaction Take?A Bitcoin transaction typically takes 10 to 60 minutes to be confirmed, depending on network congestion and the fee paid. The Bitcoin network produces a new block approximately every 10 minutes, and each block confirms a batch of transactions. Transactions with higher fees are prioritized by miners and confirm faster. For high-value transactions, waiting for six confirmations (about 60 minutes) is standard.What Is a Bitcoin Confirmation?A Bitcoin confirmation occurs when your transaction is included in a block on the blockchain. Each new block added after that provides an additional confirmation. One confirmation means your transaction is in a block and effectively permanent. Six confirmations (roughly 60 minutes) are considered the gold standard for high-value transactions, because reversing a transaction buried under six blocks would require an astronomical amount of computing power.What Is the Bitcoin Halving?The Bitcoin halving is an event that occurs approximately every four years (every 210,000 blocks) when the reward given to miners for adding a new block is cut in half. This reduces the rate at which new Bitcoin enters circulation by 50%. The most recent halving occurred in April 2024, reducing the block reward from 6.25 BTC to 3.125 BTC. Halvings will continue until approximately 2140, when the block reward becomes effectively zero.What Is Bitcoin Mining?Bitcoin mining is the process by which computers secure the Bitcoin network and process transactions by solving cryptographic puzzles. Miners compete to add new blocks of transactions to the blockchain. The winner receives a block reward (newly created Bitcoin) plus transaction fees. Mining serves two critical purposes: it issues new Bitcoin into circulation and it secures the network against attacks by making it computationally expensive to alter the blockchain.
Security and Self-Custody
How to safely store, send, and protect your Bitcoin.
Can Bitcoin Be Hacked?The Bitcoin protocol itself has never been hacked. Its security relies on SHA-256 cryptographic hashing and proof-of-work consensus, which have proven unbreakable since 2009. However, individual users can lose Bitcoin through phishing, malware, exchange failures, and poor private-key management. The network is extremely secure; the weak point is usually human error.Is Bitcoin Anonymous?Bitcoin is not anonymous; it is pseudonymous. Every Bitcoin transaction is permanently recorded on a public blockchain that anyone can view. While transactions are not directly linked to your name, sophisticated analysis can often trace Bitcoin flows and connect them to identities through exchange records, IP addresses, and spending patterns.What Is a Bitcoin Private Key?A Bitcoin private key is a secret cryptographic number that allows you to spend the Bitcoin associated with your wallet. Think of it as the ultimate password to your funds. Anyone who has your private key can control your Bitcoin, so it must never be shared with anyone. Most wallets display your private key as a 12-to-24-word seed phrase for easier backup.What Happens If You Lose Your Bitcoin Wallet?If you lose your Bitcoin wallet—whether your phone is lost, your hardware wallet breaks, or your computer crashes—your Bitcoin is not lost as long as you have your seed phrase. Your seed phrase (12-24 words) can restore your entire wallet and all your funds on any compatible device. If you lose both your wallet and your seed phrase, your Bitcoin is permanently inaccessible.What Is Cold Storage?Cold storage means keeping your Bitcoin private keys completely offline, disconnected from the internet. This protects your Bitcoin from hacking, malware, and online theft—the most common ways people lose cryptocurrency. Hardware wallets are the most popular form of cold storage. By contrast, hot wallets (connected to the internet) are convenient but more vulnerable to attack.What Is a Bitcoin Seed Phrase?A Bitcoin seed phrase is a list of 12 to 24 simple English words that serves as the master backup for your entire wallet. It can regenerate all your Bitcoin addresses, private keys, and funds on any compatible device. If you lose your phone or hardware wallet, your seed phrase restores everything. Anyone who has your seed phrase can access all your Bitcoin, so it must be kept completely private and secure.What Happens If You Send Bitcoin to the Wrong Address?If you send Bitcoin to the wrong address, the transaction cannot be reversed. If the address belongs to another person, you must contact them directly and ask them to return the funds. If the address is valid but unowned, the Bitcoin is permanently lost. There is no central authority, customer service, or recovery process that can undo a confirmed Bitcoin transaction. Prevention through careful address verification is essential.
Beginner Education
Essential concepts every new Bitcoiner should understand.
What Is a Satoshi?A satoshi (sat) is the smallest unit of a Bitcoin. One Bitcoin equals 100 million satoshis, meaning 1 satoshi is 0.00000001 BTC. Named after Bitcoin's creator Satoshi Nakamoto, satoshis allow people to buy, send, and own fractions of Bitcoin without needing to purchase a whole coin.Is Bitcoin Backed By Anything?Bitcoin is not backed by gold, government decree, or any physical commodity. Its value comes from its strict scarcity (21 million cap), the real energy and computing power required to produce it through mining, its decentralized network of thousands of nodes, and the growing global demand for a censorship-resistant store of value. Bitcoin is backed by mathematics, energy, and network effects rather than promises.Can You Buy Less Than One Bitcoin?Yes. You can buy any fraction of a Bitcoin, from a few dollars' worth to nearly a whole coin. Bitcoin is divisible to eight decimal places, and the smallest unit—called a satoshi—is 0.00000001 BTC. Most people who own Bitcoin own less than one full Bitcoin. Exchanges allow you to purchase Bitcoin in any dollar amount you choose.How Is Bitcoin Different From Cryptocurrency?Bitcoin is the first and largest cryptocurrency, but most of the thousands of other cryptocurrencies (often called 'altcoins') are fundamentally different in design, security, and purpose. Bitcoin is decentralized, has a fixed supply of 21 million, and has never been hacked. Most altcoins are controlled by small teams or foundations, have variable or unlimited supplies, and have not demonstrated Bitcoin's 16-year track record of security and uptime.What Is the Difference Between Bitcoin and Blockchain?Bitcoin is a decentralized digital currency; blockchain is the underlying technology that records Bitcoin transactions. Think of blockchain as the accounting system and Bitcoin as the money tracked by that system. While blockchain technology can be used for other applications, Bitcoin's blockchain is the most secure, decentralized, and battle-tested implementation in existence. Bitcoin and blockchain are not the same thing.
Explore Bitcoin Tools
Profit Calculator
Calculate gains, losses, and ROI.
Satoshi Converter
Convert between BTC, satoshis, and USD.
Halving History
Interactive chart of past halvings.
Disclaimer: This content is provided for general educational and informational purposes and is not financial, investment, legal, or tax advice. Bitcoin involves risk, including the possible loss of value. Consider your circumstances and consult qualified professionals when appropriate.