What's the Minimum Crypto Purchase?
The whole-coin myth, the unit maths that kills it, and the fee arithmetic that sets the real floor on a small crypto buy.
TL;DR
- You never needed to buy a whole coin: bitcoin divides into 100,000,000 satoshis and sells by the slice.
- Platform minimums vary by market and payment method, commonly a few pounds to a few tens of pounds; the quote screen has the live number.
- The real floor is flat fees: a £3 minimum fee on a £30 buy is 10% gone, while the same fee on £300 is 1%.
- Network fees add a second floor when you move coins, and balances too small to move end up as dust.
- Education only, not financial advice.
There is an uncle at every family barbecue who looked into bitcoin exactly once, saw one coin priced at a hundred grand, muttered something about tulips, and closed the tab. That was December 2024, the month a single bitcoin first crossed $100,000, and he still tells the story as proof the whole thing is for oligarchs.
He never found out you can buy a tenner's worth, because crypto sells by the slice. The unit maths behind that takes two minutes to learn, and what takes slightly longer is the fee arithmetic that decides whether a £20 purchase stays £20 of crypto or quietly becomes £16 on arrival. That second bit is what this page is actually for, and none of it is a nudge to buy anything.
One coin is 100 million pieces
Bitcoin divides into 100,000,000 units called satoshis, each worth 0.00000001 BTC. Buy £10 of bitcoin and the platform credits you the matching fraction, tracked to eight decimal places. Same as petrol: you put £10 in the tank, nobody buys the whole pump.
And bitcoin is the coarse one: Ether divides to 18 decimal places, into units called wei, and most major coins split similarly fine. Divisibility was designed in from day one, long before anyone worried about small buyers.
The pizza that proves the point
The first documented real-world bitcoin purchase was two pizzas, bought by programmer Laszlo Hanyecz on 22 May 2010 for 10,000 BTC. Divisibility cuts both ways: the network will move ten thousand coins or a fraction of one, and it does not care which.
So what is the actual minimum?
Lower than people guess, and it moves. Minimums are set per platform, per market and per payment method, and across the industry they commonly land between a few pounds and a few tens of pounds. No universal number exists, and any article quoting one goes stale fast, so check the quote screen rather than assuming.
The quote screen is where the honest numbers live anyway. Banxa has run on-ramp plumbing since 2014, with 100-plus payment methods across 100-plus countries, and a quoted price locks for roughly 3 minutes. The figure you approve is the figure you pay, for the coins and methods available in your market.
The real floor is the flat fee
Forget the platform minimum for a second, because the thing that decides whether a small buy makes sense is the flat fee.
Fees on small purchases often carry a flat minimum rather than a straight percentage: a £3 minimum fee on a £30 purchase is 10% of your money gone before the price so much as twitches, and the same £3 on £300 is 1%. The platform did nothing different between those two orders, the arithmetic did everything.
Payment method shifts the floor too: cards run roughly 3 to 5% all-in and settle fast, with orders typically complete within about 10 minutes of issuer approval, and bank transfers run closer to 1% and take longer. That gap barely registers on a £500 order and dominates a £20 one.
So the better question is how small you can go while the fee percentage stays boring. Boring is the goal.
What happens when you move the coins
Buying is half the cost picture: move coins from the platform to your own wallet later and the network charges its own fee, which does not scale down for small balances.
Ethereum's gas pricing, reworked by EIP-1559 in August 2021 so the base fee is burned rather than paid to miners, still makes tiny ETH withdrawals disproportionately dear in busy periods. Bitcoin fees are bid per byte of block space, and around the 20 April 2024 halving, the day the Runes protocol launched, average fees briefly hit records. Solana sits at the other end: transfers cost a fraction of a cent.
Which is why a £5 balance can be worth £5 on the platform and close to nothing once you try to move it.
Small is normal, dust is the failure mode
Plenty of first purchases are £20 or £50, run mostly to watch the mechanics work before anything bigger. That is fine. It is how a lot of people learn the system without sweating the outcome, and none of this is financial advice.
The failure mode has a name: dust, a balance too small to be worth the fee to move it. Buy tiny, let a flat fee shave the entry, pay a network fee on the way out, and what remains can cost more to transfer than it holds. Every long-time holder has a little dust somewhere, and it is mildly annoying every single time.
So run one sum before any small buy: fee divided by amount. A double-digit answer means the purchase is mostly a donation to fees, and waiting until that percentage looks boring costs nothing. The minimum that matters is the point where fees stop eating the point of the purchase, and only the quote screen can tell you where that sits today.
Frequently Asked Questions
Yes, and almost everyone does. Bitcoin divides into 100,000,000 satoshis, so a £10 purchase buys a slice tracked to eight decimal places. The whole-coin price is just a unit label. Nobody charges it at the door.
It depends on the coin, your market and the payment method, in the markets Banxa serves. Industry minimums commonly sit between a few pounds and a few tens of pounds, and the quote screen shows the live floor before any money moves. Quotes lock for roughly 3 minutes.
The fee decides that more than the amount does. A flat £3 minimum fee turns a £10 buy into a 30% haircut before prices move, while the same fee on £300 is 1%. Run that sum on the quote screen and judge the percentage. Whether to buy at all is your call; this page does not give investment advice.
A balance too small to be worth the network fee to move it. Buy tiny amounts, let fees shave the edges, and you can end up with a remnant that costs more to transfer than it holds. Mostly harmless, mildly annoying, and the usual end state of too-small purchases.
Most divide finer. Ether splits to 18 decimal places, into units called wei, and the big coins follow suit. Divisibility has been there from the start: the 10,000 BTC pizza purchase of 22 May 2010 ran on the same rails as a £10 buy does today.
Cards run roughly 3 to 5% all-in against about 1% for bank transfers, because card rails price in speed and fraud handling. That gap fades into the noise on big orders and dominates small ones, which is why patient buyers often pair small amounts with a transfer, where available.