Cryptocurrency for Beginners

Understanding how crypto works starts with the ledger. In ordinary banking, your balance is a number in your bank's private database. In crypto, balances are recorded on a public ledger called a blockchain, copied across thousands of computers around the world. No single company keeps the master copy, and anyone can check the history. That design removes the need to trust one institution, but it also removes the institution that could fix a mistake for you.

The blockchain in plain terms

A blockchain is a chain of blocks, each holding a batch of transactions and a fingerprint (a cryptographic hash) of the block before it. Changing an old transaction would change its fingerprint and break every block that follows, which is why the history is so hard to rewrite.

New blocks are added by participants who follow the network's rules:

• Proof of work, used by Bitcoin, asks miners to spend computing power solving a puzzle. The winner adds the next block and earns a reward.
• Proof of stake, used by Ethereum since 2022, asks validators to lock up coins as a deposit. Validators who break the rules can lose part of that deposit.

Coins, tokens and stablecoins

For a deeper look at the two best-known assets, read what Bitcoin is and our explainer on USDT. For newly launched tokens, see new crypto coins.

Wallets and keys

A crypto wallet does not hold coins in the way a purse holds cash. The coins stay on the blockchain; the wallet holds the private key that proves you are allowed to move them. Most wallets back up that key as a seed phrase of 12 or 24 words.

• Custodial: an exchange holds the keys for you. Convenient, but you rely on the exchange's security, solvency and willingness to let you withdraw.
• Self-custody: you hold the keys, in a phone app (hot wallet) or a dedicated hardware device (cold wallet). Nobody can freeze your funds, but nobody can recover them if you lose the phrase either.

How crypto works when you buy through an exchange

Most people buy their first crypto through a centralised exchange. You pass identity checks, deposit money by bank transfer or card, then place an order on the exchange's order book. The coins you buy are recorded in the exchange's internal ledger; they only move on the blockchain if you withdraw them to another address.

When you withdraw, you choose the network, paste the destination address and pay a network fee. Blockchain transfers are final: if the address or network is wrong, the funds are usually gone. Always send a small test amount first when using a new address.

Fees add up in several places. As an illustration, buying $500 of a coin through an "instant buy" button that builds in a 1.5% spread costs $500 × 1.5% = $7.50 before you have made or lost anything on the price. Placing an order on the exchange's order book is often cheaper. Our crypto profit calculator shows how fees on both the buy and the sell affect your result.

Choosing where to learn and where to buy

Cryptocurrency websites range from careful explainers to sites that earn a commission every time you sign up somewhere. Treat a page that pushes one exchange or one coin with a countdown timer as advertising, not information. Before using any exchange, check whether it is registered or licensed in your country, how it holds customer assets, what it charges to withdraw and whether it publishes regular evidence of its reserves. Our broker and exchange checklist goes through each step.

Centralised and decentralised exchanges

A centralised exchange is a company. It runs the order book, holds customer funds, checks identities and sets its own rules. If it is regulated, you have some recourse; if it fails, your balance may be caught up in its insolvency.

A decentralised exchange is software on a blockchain. You trade directly from your own wallet against pools of tokens supplied by other users, and nobody holds your funds for you. That removes the custody risk of a company, but replaces it with other risks: bugs in the code, look-alike tokens listed by anyone, and approvals that can let a malicious contract move your tokens. There is usually no support team and no one to reverse an error.

Where a coin's price comes from

A share has a company behind it with revenue that analysts can study. Most coins do not. The price of a cryptocurrency is simply the most recent level at which a buyer and seller agreed to trade. It reflects expectations about future use, the size and timing of new supply, how easy the coin is to buy through mainstream channels, and the general mood of the market. When that mood changes, there is little to slow the move, which is why crypto can fall by a large amount in a short time.

Prices also vary slightly between exchanges because each has its own order book. On a small exchange with few buyers, selling even a modest amount can push the price down noticeably. That is a practical reason to check liquidity before buying anything outside the largest coins.

A first-purchase checklist

• Decide in advance how much you are prepared to lose entirely, and keep to it.
• Use a platform that is registered or licensed where you live, reached by typing its address yourself rather than through an advert or message.
• Turn on app-based two-factor authentication rather than SMS where possible, and use a unique password.
• Check the fee on the trade and the fee to withdraw before you buy.
• Keep a record of every purchase, sale and transfer; many countries tax crypto gains and you will need the history.
• Ignore anyone who offers to "manage" your crypto or promises a fixed return.

Risks specific to crypto

• Volatility. Double-digit daily moves are common, especially in smaller tokens.
• Platform failure. Exchanges have collapsed or been hacked, and compensation schemes rarely cover crypto.
• Irreversible mistakes. Wrong network, wrong address or a signed malicious transaction cannot be undone.
• Scams. Fake exchanges, investment "mentors", romance scams and recovery scams are widespread. Read how to spot trading scams.
• Regulation. Rules differ by country and change often. In the UK, crypto derivatives cannot be sold to retail consumers.

Sources

• UK Financial Conduct Authority, ban on the sale of crypto-derivatives to retail consumers
• Ethereum Foundation documentation on proof of stake
• Bitcoin white paper, Satoshi Nakamoto (2008)