Buying · Explainer
Buying a Fraction of Bitcoin: What $20, $50 or $100 Really Costs
Can you buy a fraction of bitcoin? Yes. See what a satoshi is, how flat fees weigh on small orders of $20, $50 or $100, and how minimums can leave coins stuck.
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- How2BuyCrypto Editorial
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- Updated
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- 9 min read
Written with AISources checked How our guides are made
At a glance
- You can buy a fraction of a bitcoin. One bitcoin is 100,000,000 satoshis, so 0.001 BTC and 100,000 sats are the same amount.
- A percentage fee takes the same share of any order. A flat fee takes a larger share of a small one.
- Order, step and withdrawal minimums differ by platform, so a small order can end up below one.
- Do not use a Bitcoin ATM or pay in crypto because someone tells you to.
On this page10 sections
- What is a satoshi? How to buy part of a bitcoin
- Small Bitcoin purchase fees: flat costs and percentage costs
- Example with made-up numbers: $20, $50 and $100 orders
- Minimum Bitcoin withdrawal and other minimums
- Sending Bitcoin out or leaving it on the platform
- Other costs to watch on small purchases
- Checks before you confirm a small order
- Risks to understand
- Frequently asked questions
- Sources
Can you buy a fraction of bitcoin? Yes. You can buy small amounts of Bitcoin, such as $20, $50 or $100, because you choose how much money to spend and the platform gives you the matching fraction of a coin. What changes with size is cost: some fees are flat, so they take a bigger share of a small order. Before you confirm, work out the fees as a share of what you pay, and check the Bitcoin you will receive against your platform's minimums.
What is a satoshi? How to buy part of a bitcoin
Do you need to buy a whole bitcoin? No: transactions can be denominated in smaller sub-units (opens in a new tab) of a bitcoin. A satoshi (sat) is the smallest unit. There are 100,000,000 satoshis in 1 bitcoin (opens in a new tab), and bitcoin can be divided up to 8 decimal places, so the smallest amount is 0.00000001 BTC, one satoshi. Sats and BTC are two ways to write the same amount.
| BTC | Satoshis | In words |
|---|---|---|
| 1 | 100,000,000 | One bitcoin |
| 0.001 | 100,000 | One thousandth |
| 0.00001 | 1,000 | One hundred-thousandth |
| 0.00000001 | 1 | One satoshi |
On a simple buy screen you enter the money to spend, and the platform works out the coins:
BTC received = (amount spent minus fees) divided by the price per bitcoin
Fees come out of what you spend. A fraction is the same asset as a whole coin. Its value is your BTC amount times the price, so it rises and falls by the same percentage.
Small Bitcoin purchase fees: flat costs and percentage costs
Some costs scale with the order and some do not. A percentage fee takes the same share of a $20 order and a $100 order. A flat fee takes a larger share of the smaller one.
Costs that scale with the order, when your platform quotes them as a percentage:
- Trading fee, charged when you place the order.
- Card or deposit fee, charged when you add money.
- Spread, a cost built into the price per coin. The spread on simple and advanced screens explains it.
Costs that stay the same whatever you buy:
- Any flat fee per order. If the fee page lists a fixed amount or a minimum fee, divide it by your order to see its share.
- The network fee for sending Bitcoin out. It does not depend on the amount you send (opens in a new tab), and it varies over time with demand for space on the blockchain.
- A platform's own withdrawal fee, which may bundle the network fee.
If you pay in another currency, look for a conversion charge on the order screen. The order screen should show the total, and the withdrawal screen should show what a send costs.
As of October 2026, two US platforms' own pages show how a percentage can fall as the order grows:
- PayPal's US fee page (opens in a new tab) lists 2.20% on crypto purchases of $1.00 to $74.99, 2.00% from $75.00, 1.80% from $200.01 and 1.50% from $1,000.01.
- Cash App in the US (opens in a new tab) lists 2.0% on its market buys of $1 to $499, 1.5% for $500 to $999, 0.9% for $1,000 to $1,999 and 0% from $2,000.
Each is one platform's policy, not how every platform works.
Example with made-up numbers: $20, $50 and $100 orders
The price and fees below are invented and no platform is named. Your platform may label and group these amounts differently.
Assume the price per bitcoin shown on the buy screen is $50,000. A flat $1 fee and a 1% fee come out of the total you pay. Deposit fees are left out.
| Total paid | Fees ($1 + 1%) | Spent on bitcoin | BTC received | Fees as share of total |
|---|---|---|---|---|
| $20 | $1.20 | $18.80 | 0.000376 | 6.0% |
| $50 | $1.50 | $48.50 | 0.00097 | 3.0% |
| $100 | $2.00 | $98.00 | 0.00196 | 2.0% |
The flat fee is 5% of the total when you buy $20 of Bitcoin and 1% when you buy $100 of Bitcoin. The 1% fee is 1% of both.
Divide the total paid by the coins received to see what you paid per bitcoin, against the $50,000 price shown on the buy screen: about $53,191 for the $20 order, $51,546 for the $50 order and $51,020 for the $100 order.
Now add two invented limits. A platform can set an order step, a unit that orders must be a multiple of. Gemini says (opens in a new tab) orders on its exchange are strictly held to its minimums and increments. With a step of 0.0001 BTC, the $20 order's 0.000376 BTC is off the step, so the platform could refuse it or reduce it to 0.0003 BTC. Check the BTC amount on the confirmation screen, not only the money amount.
Then suppose the withdrawal minimum is 0.0005 BTC and a send pays a network fee of 0.00005 BTC. The 0.000376 BTC from the $20 order is below the minimum, so it cannot be sent. The other two clear it. The invented network fee would be about 5.2% of the 0.00097 BTC and about 2.6% of the 0.00196 BTC.
Minimum Bitcoin withdrawal and other minimums
Each platform sets its own minimums, and three of them decide the smallest amount of Bitcoin you can buy and move. Look for them on the order screen or in the help pages, and see payment methods compared for funding costs and holds.
As of October 2026, from the platforms' own pages:
- Order amount, the least money an order can use. Kraken's help page lists (opens in a new tab) a minimum of 1 USD, 1 EUR, 1 GBP, 1 CAD, 1 CHF, 1 AUD or 110 JPY to buy or sell, and a higher minimum for card purchases of 10 EUR, 10 USD, 14 AUD, 8 GBP, 12.50 CAD or 10 CHF.
- Order size, the least bitcoin an order can be, counted in BTC. Kraken's documentation (opens in a new tab) defines its minimum order size as counted in the base currency. Its public market data (opens in a new tab) lists 0.00005 BTC (5,000 sats) for bitcoin against the US dollar on its exchange.
- Withdrawal, the least BTC you can send out. PayPal's US help page (opens in a new tab) lists 0.001 BTC (100,000 sats) for external bitcoin transfers. Its fee page (opens in a new tab) says the network fee is shown right before you transfer. Bitbuy in Canada lists 0.0006 BTC (opens in a new tab), with a "Dynamic" fee set by current network conditions and shown on the withdrawal screen. Cash App in the US lists (opens in a new tab) a "minimum withdrawal of ₿100,000" for its standard-speed withdrawals, which it says carry no fee. Its page does not say which unit that figure uses, so check the amount in the app.
These are examples that differ, not typical values. Compare the BTC amount on your order screen with each minimum before you confirm. If an order is below one, it may be refused: raise the amount, or ask support if you cannot find the figure. Before you send Bitcoin to another platform, check its deposit help for a minimum deposit too.
What to do with a leftover balance
A balance below the minimum order size may not be sellable as a normal order, and one below the withdrawal minimum cannot be sent. Before you sell most of your balance, check what would remain. If it would fall below a minimum, look in the help pages for a small-balance option and read its fee on the preview before you confirm. The first question below names one example.
Sending Bitcoin out or leaving it on the platform
Each send is charged a network fee, which the platform may pass on to you. At the same moment, sending $20 of Bitcoin costs the same network fee as sending a much larger amount, so sending the same total in fewer, larger sends pays that fee fewer times.
Before you move anything, read how to send crypto to a wallet. If your platform offers a choice of network when you withdraw, Bitcoin network or Lightning explains it.
On the withdrawal screen, find the fee before you confirm. If it shows one fee, check whether it includes the network fee. Divide the fee by the amount you are sending.
If the share is more than you want to pay, leave the coins where they are or send fewer, larger amounts. Leaving Bitcoin on the platform takes no extra steps, but you depend on the platform to keep it, and how to store crypto safely covers what that means.
Other costs to watch on small purchases
As of October 2026, a few things add cost to small orders.
Cards, simple-buy spreads and recurring buys
- Card payments. Kraken says (opens in a new tab) additional fees may apply depending on the payment method, such as a credit or debit card. Debit card vs bank transfer compares fees and holds.
- Simple-buy spreads. Cash App in the US says (opens in a new tab) any spread is included in the price on the confirmation screen. Bitbuy in Canada says (opens in a new tab) it quotes trades using a spread instead of charging trading fees. Kraken's fee page says the price you see on its instant buy service includes a spread. No separate fee line does not mean no cost; the checks before you confirm show how to find it.
- Recurring buys. Some platforms charge a fee on each one. Kraken's fee page lists 1% for instant and recurring trades, while Cash App in the US says Auto Invest has zero fees and zero spread. If your platform adds a flat fee to every order, a plan of small orders pays it each time, so read the recurring-buy line on the fee page.
Bitcoin ATMs
Look for the fee and the rate on the machine's screen before you insert cash. If you cannot find them, do not use it. Bitcoin ATM scams and how to spot one covers the warning signs.
- United States: in a September 2024 alert (opens in a new tab), the FTC warned not to believe anyone who says you need to use a Bitcoin ATM to protect your money or fix a problem.
- United Kingdom: the FCA said in May 2023 (opens in a new tab) that no crypto ATM operators are registered with it, which they must be to operate legally.
- Australia: in a June 2025 Australian Federal Police release (opens in a new tab), AUSTRAC said it had placed conditions on crypto ATM operators, including an A$5,000 transaction limit.
- Elsewhere: check your country's financial regulator.
Checks before you confirm a small order
- Add up every fee line on the order screen and divide by the total you will pay. The spread is not a fee line: divide the total you pay by the BTC you receive, and compare that price per coin with the price shown before fees. If a fee is higher than the fee page says, stop and ask support.
- Find how much BTC you will receive. Compare it with the order-size step and, if you plan to withdraw it, with the withdrawal minimum.
- If the screen shows no total, fee or BTC amount, do not confirm.
The rest of the checklist is in how to buy Bitcoin step by step. To choose a platform first, read how to choose a crypto exchange. Whether the coins then sit with the platform or in a wallet you control is a separate choice, covered in what you hold when you buy.
Risks to understand
- Price swings. Buy only an amount you could lose in full. Risks to understand in the Bitcoin guide covers price swings, platform failure and missing insurance.
- Fee-to-unlock scams. The Australian Federal Police advises (opens in a new tab) that if someone, a business or a government agency asks you to pay using cryptocurrency, you should not send money. Treat a request for a fee in crypto before you can withdraw or receive anything the same way. Read how to spot crypto scams.
Before you buy, read how to buy Bitcoin for the steps.
Frequently asked questions
What happens to a balance below the withdrawal minimum?
You cannot send it out until it reaches the minimum, so it stays on the platform until you add enough to clear it. As of October 2026, some platforms offer a paid tool for small leftovers. Kraken's fee page lists a fixed 3% fee to convert small balances below its minimum order size. The tool converts the balance; it does not send it out. Check your own platform's withdrawal help page for what it says.
Does the spread change with order size?
It depends on the platform. As of October 2026, Cash App's US fee page says its spread may be anywhere from 0% to 0.75% depending on market conditions, and that buys over $2,000, Auto Invest, Round Ups and direct deposit are spread-free. To check yours, open the buy screen without confirming and note the price per coin shown before fees at a $20 amount and a $100 amount. A flat fee or tiered rates change the total you pay, not that price. If the price before fees differs, ask support why before you buy.
Can I send a small amount of Bitcoin to someone else's wallet?
Yes, if the amount is at or above your platform's withdrawal minimum and the network fee still leaves something worth sending. A send cannot be undone, so crypto sent to the wrong recipient, to the wrong address or over an unsupported network is lost. Use the network and address the recipient gives you, and compare the whole pasted address with theirs before you confirm. Ask the recipient to confirm the coins arrived.
Can you own less than one satoshi?
Not on the Bitcoin network, where the smallest amount is one satoshi (0.00000001 BTC). As of October 2026, Gemini, a US exchange, says its own records can show finer amounts, such as a trade of 0.0000000001 BTC. Do not assume an amount that small can be sent out.
Sources
- Frequently Asked Questions, bitcoin.org. Accessed .
- How do I transfer my crypto?, PayPal (US). Accessed .
- PayPal Consumer Fees, PayPal (US). Accessed .
- Bitcoin fees, Cash App (Block, Inc.). Accessed .
- Fee schedule, Bitbuy (Coinsquare Capital Markets Ltd.). Accessed .
- Fee schedule, Kraken (Payward). Accessed .
- FAQ's about buying instantly, Kraken (Payward). Accessed .
- Get Tradable Asset Pairs (REST API), Kraken (docs.kraken.com). Accessed .
- Precision on the Exchange, Gemini (developer.gemini.com). Accessed .
- Scammers use Bitcoin ATMs to steal your money, Federal Trade Commission. Accessed .
- FCA continues action against unregistered crypto ATMs across the UK, Financial Conduct Authority. Accessed .
- Tapped out: Authorities target criminal use of cryptocurrency ATMs in nationwide action, Australian Federal Police. Accessed .
This guide was researched and written with AI using the sources above. It is general information, not financial advice. Cryptoassets are volatile and you could lose the money you invest. Check the rules in your country before you buy. Some links on this site may be affiliate links; they never change what we write. Spotted an error? Email contact@how2buycrypto.org.