Bitcoin addresses start with 1, 3, or bc1, depending on the type of wallet that created them

A Bitcoin address is a string of letters and numbers that works like an account number — it tells the Bitcoin network where to send coins. The first character of that address tells you something important: which format the wallet used to create it. If an address starts with 1, it uses the oldest format. If it starts with 3, the wallet added extra security. If it starts with bc1, the wallet is using the newest standard. None of these is "better" — they all work — but they do affect transaction speed and cost.

The starting character is not random. It is built into the address itself by the wallet software when it generates a new address for you. You cannot change it, and you do not need to. What matters is that you copy the full address correctly when you send or receive Bitcoin, because even one wrong letter will send the coins to the wrong place or cause the transaction to fail.

Key Takeaways

  • Bitcoin addresses that start with 1 are the original format and still work, but they cost slightly more in transaction fees than newer formats.
  • Addresses starting with 3 add a layer of security called multi-signature capability, though most wallets do not use this feature.
  • Addresses starting with bc1 are the newest standard and usually have the lowest transaction fees.
  • The starting character is determined by your wallet software and cannot be changed — it is part of how the address is encoded.
  • You must copy the entire address exactly when sending or receiving Bitcoin; a single wrong character will cause the transaction to fail or go to the wrong place.

Addresses starting with 1: the original Bitcoin format

The first Bitcoin addresses, created in 2009, all started with the number 1. This format is called P2PKH (Pay to Public Key Hash), and it is still in use today. When you see an address like 1A1z7agoat4wr8BsxEFSc9exJersRqJ2d, you are looking at this original type.

These addresses work perfectly fine. You can send Bitcoin to them and receive Bitcoin from them without any problems. The trade-off is that they cost slightly more in transaction fees than the newer formats do. This is because the Bitcoin network charges fees partly based on the size of the transaction data, and P2PKH transactions are larger than newer types. If you are sending a small amount, the difference might be a few cents. If you are moving a large amount, it could be several dollars.

Many older wallets and exchanges still use this format by default. If your wallet was created years ago and you have never changed the settings, your addresses probably start with 1. There is no security problem with this — it just means you might pay slightly more per transaction than someone using a newer format.

Addresses starting with 3: multi-signature capability built in

Addresses that start with 3 use a format called P2SH (Pay to Script Hash). This format was introduced in 2012 to support more complex transaction rules. The most common use is multi-signature addresses, which require more than one private key to spend the Bitcoin.

For example, a multi-signature address might require two out of three private keys to approve a transaction. This means that if one key is stolen or lost, the Bitcoin is still safe — a thief cannot spend it alone, and you cannot accidentally lose it if you misplace one key. Some businesses and high-value holders use this setup for security. However, most individual users do not, because it adds complexity and requires managing multiple keys.

Even if a 3-address is not using multi-signature, it still works like any other address. You can send Bitcoin to it and receive Bitcoin from it. The transaction fees are lower than P2PKH (1-addresses) but usually higher than the newest format (bc1-addresses). If you see a 3-address and you are not sure what it is, you can safely assume it is a standard address and send Bitcoin to it without worry.

Addresses starting with bc1: the newest standard

Addresses that start with bc1 use a format called SegWit (Segregated Witness), introduced in 2017. These addresses are longer and use both letters and numbers — for example, bc1qw508d6qejxtdg4y5r3zarvary0c5xw7kv8f3t4. They are the newest standard and are becoming more common.

The main advantage of bc1-addresses is lower transaction fees. Because SegWit transactions are encoded more efficiently, the Bitcoin network counts them as smaller, which means lower fees. Over time, as more wallets and exchanges adopt this format, the fee savings will likely grow. Many modern wallets now create bc1-addresses by default.

Not every service accepts bc1-addresses yet, though this is changing rapidly. Some older exchanges or wallets may reject them or display an error message. If you are sending Bitcoin to a service and they give you an error when you paste a bc1-address, contact their support — they may need to update their system, or they may ask you to use a different address format instead. Most services created in the last few years support bc1 without any problem.

Why the starting character matters for fees but not for security

The starting character affects transaction fees because it determines how the Bitcoin network counts the size of your transaction. A 1-address transaction takes up more data space than a bc1-address transaction, so the network charges more to process it. This is purely a technical difference, not a security difference.

All three formats are equally secure. A thief cannot steal Bitcoin from a 1-address more easily than from a bc1-address. The security of your Bitcoin depends on keeping your private key secret, not on which address format you use. If someone has your private key, they can spend your Bitcoin regardless of whether the address starts with 1, 3, or bc1. If they do not have your private key, they cannot spend it, no matter what format it is.

How to tell if an address is valid before you send Bitcoin

Before you send Bitcoin to an address, check that it starts with 1, 3, or bc1. If an address starts with anything else, it is not a valid Bitcoin address — it might be an Ethereum address or some other cryptocurrency, and sending Bitcoin to it will result in lost coins.

Also check that the address is long enough. A 1-address or 3-address should be 26 to 35 characters long. A bc1-address should be 42 to 62 characters long. If the address is much shorter or longer, something is wrong.

The safest practice is to copy and paste the address directly from the source rather than typing it by hand. If you must type it, double-check the first few characters and the last few characters — these are the easiest places to make a mistake, and they are the most important to get right. Many wallets will warn you if you paste an address that does not look right, but not all of them do.

What happens if you send Bitcoin to the wrong address format

If you send Bitcoin to a valid address that is not yours, the transaction will go through and the coins will belong to whoever controls that address. There is no way to reverse it. Bitcoin transactions are permanent.

However, if you send Bitcoin to an address that is not valid — for example, an address that is too short or has a typo — the transaction will usually fail before it is sent. Your wallet software checks the address format and will show an error message. This is a safety feature built into most wallets.

If you send Bitcoin to an address that starts with a different cryptocurrency's prefix (like an Ethereum address), the transaction may fail, or it may go through and the coins will be lost. This is why checking the first character is so important — it is your first line of defense against sending coins to the wrong place.

Frequently Asked Questions

Can I change what my Bitcoin address starts with?

No. The starting character is determined by your wallet software and is built into the address itself. You cannot change it. However, most wallets let you create multiple addresses, and different addresses may use different formats. Check your wallet settings to see if you can generate a new address in a different format.

Is a bc1 address safer than a 1 address?

No. Both are equally secure. The only difference is transaction fees — bc1 addresses usually cost less to send from. Security depends on keeping your private key secret, not on the address format.

Why do some exchanges only give me 1 addresses?

Older exchanges and wallets were built before bc1 and 3 addresses existed, and some have not updated their software. This is not a problem — 1 addresses still work perfectly. If you want lower fees, you can ask the exchange if they support other formats, or you can transfer your Bitcoin to a modern wallet that uses bc1 addresses.

What if I accidentally send Bitcoin to a 3 address when I meant to send to a 1 address?

If both addresses are valid and belong to the person you intended to send to, the Bitcoin will arrive safely. The format does not matter — what matters is that the address belongs to the right person. If you sent to the wrong person entirely, the transaction cannot be reversed.

Do I need to know the address format to receive Bitcoin?

No. You just give someone your address and they send Bitcoin to it. Your wallet will handle the rest. The format does not affect how you receive — only how much the sender pays in fees when they send to you.