The lesson in three lines
- A cryptocurrency is a balance on a shared public ledger, and whoever controls the private key controls the coins.
- Most beginners buy through an exchange, which usually holds the coins for them; moving coins to your own wallet shifts that responsibility to you.
- Prices are highly volatile, transfers cannot be reversed and protections are thin, so scams and simple mistakes are costly.
This lesson explains how crypto works without assuming any technical background. Coins and tokens can seem abstract, but the system rests on a few concrete ideas: a shared record of who owns what, a way of proving you are allowed to move your share of it, and a network of computers that agrees on the next page of the record.
The ledger: a record everyone can check
A traditional bank keeps its own private record of balances. A cryptocurrency network keeps a public ledger copied across thousands of computers, called nodes. New transactions are grouped into blocks, and each block contains a fingerprint of the one before it, forming a blockchain. Changing an old entry would change every fingerprint after it, which the rest of the network would reject.
Different networks agree on new blocks in different ways. Bitcoin uses proof of work: computers compete to solve a puzzle and the winner adds the next block. Ethereum and many newer networks use proof of stake, where validators lock up coins as a guarantee of honest behaviour. Our Bitcoin lesson covers the first in detail.
Keys, wallets and addresses
Coins never sit in a wallet the way cash sits in a purse. They stay on the ledger. What a wallet holds is a private key: a secret number that proves you may move the coins linked to a matching address. The address is safe to share; the key, or the seed phrase of 12 or 24 words that can rebuild it, must never be shared with anyone.
- Custodial: an exchange or app holds the keys and shows you a balance. Convenient, but you depend on that firm staying honest and solvent.
- Self-custody: you hold the keys in a software or hardware wallet. Nobody can freeze your coins, but nobody can restore them if the seed phrase is lost or stolen either.
Each blockchain has its own address format, and many tokens exist on more than one chain. An address that works on one network may look valid on another yet lead nowhere useful. Before any transfer, confirm that the sending platform, the receiving address and the token all refer to the same network. Wallet apps are also impersonated: download them only from the maker's official site or a verified store listing, and check the publisher name before installing.
How crypto works on an exchange
Most beginners start on a centralised exchange. You pass identity checks, pay in local currency and buy coins from other users through an order book, much like a stock exchange. The coins usually remain in the exchange's wallets, and your account shows a claim on them.
A worked purchase
Illustrative only: you spend $200 on Bitcoin when the price is $60,000 and the exchange charges a 0.1% trading fee. The fee is $0.20, so $199.80 buys 199.80 ÷ 60,000 = 0.00333 BTC. If the price later rises to $62,000, that is worth about $206.46 before the selling fee; if it falls to $54,000, about $179.82. The crypto profit calculator works through both legs of the fee for you.
Other routes include decentralised exchanges, which are smart contracts that swap tokens directly from your own wallet, and derivatives such as futures, which track a coin's price with leverage. In the UK, crypto derivatives cannot be sold to retail consumers, and in the EU retail crypto CFDs are capped at 2:1.
Coins, tokens and stablecoins
- Coins such as bitcoin or ether are native to their own blockchain and are used to pay its transaction fees.
- Tokens are created on top of an existing blockchain by a smart contract. Anyone can create one in minutes, which is why so many exist.
- Stablecoins such as USDT aim to hold a steady value, usually one US dollar, backed by reserves held by the issuer. See what USDT is for how that works and where it can fail.
Thousands of small tokens trade every day. Our page on small crypto explains why their prices can be misleading and why lists of "top picks" deserve suspicion.
What gives a cryptocurrency value?
A share has a claim on company profits; a bond has promised interest. Most cryptocurrencies have neither. Their price comes from what other people are willing to pay, which in turn depends on things such as how widely a network is used, how its supply is managed, how easy it is to buy and sell, and a great deal of sentiment. Some tokens give holders a role in running a protocol or a share of its fees; many give nothing at all.
That is why crypto prices can double or halve on changes in mood alone. Understanding this is not a reason to buy or avoid any coin, but it explains why valuation methods used for shares rarely apply.
Fees you will meet
- Trading fees, a percentage of each buy and sell, sometimes lower for orders that add liquidity to the book.
- Spreads, the gap between buy and sell prices, which can be wide on "simple buy" screens.
- Network fees, paid to the blockchain when coins are moved, which vary with how busy the network is.
- Withdrawal fees, charged by the exchange when you move coins or cash out.
Trading fees explained puts these on one example.
Following prices with a crypto tracker
A crypto tracker is a website or app that collects prices from many exchanges and shows them in one place, often with market value, trading volume and portfolio tools. It can be useful for seeing how a coin trades across venues, but remember that prices differ slightly between exchanges, that volume figures for small tokens can be inflated, and that connecting a tracker to your exchange account should only ever use read-only access. A tracker is not a recommendation engine; a coin appearing near the top of a list says nothing about whether it suits you.
The main risks
- Volatility: falls of 50% or more have happened repeatedly in major coins, and far worse in small tokens.
- Irreversible transfers: a payment to the wrong address or the wrong network is usually lost for good.
- Platform failure: exchanges have collapsed or been hacked, and customer balances are often not covered by any compensation scheme.
- Scams: fake apps, impersonators and "recovery" services target crypto users heavily; see how to spot trading scams.
- Rules: regulation differs by country and continues to change.
Records and tax
Many countries treat selling, swapping or spending crypto as an event that may be taxed, even when no cash is involved. Swapping one token for another can count. Rules vary widely, so check the guidance from your own tax authority. Whatever the rules, keep a record of every purchase, sale, transfer and fee, including dates and prices in your local currency. Exchanges can close or lose data, and rebuilding years of history later is painful.
A short checklist before your first purchase
- Understand what you are buying and why it has value to anyone.
- Check the platform is registered or licensed where you live; see how to choose a broker or exchange.
- Turn on two-factor authentication and use a unique password.
- Send a small test amount before any large transfer.
- Decide in advance how much you are prepared to lose.
Beginner questions
Is crypto the same as money in a bank?
No. A bank deposit is a claim on a regulated bank, often covered by a deposit guarantee. Crypto is a balance on a public ledger or on an exchange's books, with no guarantee of value and usually no compensation scheme.
Can a crypto transaction be cancelled?
Almost never. Once a transfer is confirmed on the blockchain it cannot be reversed by the sender, the exchange or the network. Always check the address and network before sending.
Do I need a wallet to buy crypto?
Not to start. An exchange account holds the coins for you. A personal wallet gives you direct control, but also full responsibility for keeping the keys safe.
Sources
- UK Financial Conduct Authority, ban on crypto-derivatives for retail consumers
- European Securities and Markets Authority, CFD product intervention measures