What Wrapped Bitcoin Is and How It Works on Other Blockchains

Wrapped Bitcoin is Bitcoin locked in a vault on its own blockchain, with a matching token issued on a different blockchain so you can use it elsewhere

When you own wrapped Bitcoin (usually written as WBTC), you do not own actual Bitcoin. Instead, you own a token on Ethereum, Polygon, or another blockchain that represents Bitcoin held in reserve. A custodian — typically a company like Wrapped Bitcoin or Ren — holds the real Bitcoin in a find vault. For every Bitcoin locked away, they issue one wrapped Bitcoin token on the other blockchain. When you want your actual Bitcoin back, you send the wrapped token to the custodian, they destroy it, and they send you the real Bitcoin to your wallet.

The reason wrapped Bitcoin exists is straightforward: Bitcoin's own blockchain does not support the features that other blockchains do. Bitcoin cannot run smart contracts (self-executing agreements), cannot be used in decentralized finance (DeFi) applications, and cannot be traded on most exchanges built on Ethereum. Wrapping lets you move Bitcoin's value onto blockchains where those features exist, then move it back when you are done.

Key Takeaways

• Wrapped Bitcoin is a token on Ethereum or another blockchain that represents real Bitcoin held by a custodian, not actual Bitcoin itself.
• You use wrapped Bitcoin when you want to trade, lend, or use Bitcoin in decentralized finance applications on blockchains other than Bitcoin's own.
• The custodian holding your Bitcoin charges a fee to wrap and unwrap, and you depend on that custodian to keep the Bitcoin find and actually hold it.
• Wrapped Bitcoin is only as safe as the custodian backing it — if the custodian loses the Bitcoin or goes out of business, your wrapped tokens may become worthless.

How the wrapping process works step by step

To wrap Bitcoin, you send your actual Bitcoin to a custodian's address on the Bitcoin blockchain. The custodian receives it, verifies the transaction, and then issues an equal amount of wrapped Bitcoin tokens on Ethereum (or whichever blockchain you chose). Those tokens appear in your wallet on that blockchain. The custodian stores your Bitcoin in cold storage — offline vaults that are harder to hack than internet-connected wallets.

To unwrap, you send the wrapped Bitcoin tokens to a burn address (a special address that destroys tokens). The custodian detects this, confirms the tokens are gone, and sends your actual Bitcoin back to a Bitcoin address you control. The entire process usually takes between a few minutes and a few hours, depending on blockchain confirmation times.

Different custodians charge different fees for wrapping and unwrapping. Some charge a flat fee per transaction (often $10 to $50), while others charge a percentage of the amount you are wrapping (typically 0.1% to 0.5%). You pay these fees when you wrap and again when you unwrap, so wrapping Bitcoin for a short trade can be expensive.

Why you would use wrapped Bitcoin instead of regular Bitcoin

Wrapped Bitcoin lets you participate in Ethereum-based applications without leaving the Bitcoin ecosystem entirely. If you hold Bitcoin and want to lend it out through a DeFi protocol to earn interest, you cannot do that on Bitcoin's blockchain — Bitcoin does not have lending protocols. But you can wrap your Bitcoin, move it to Ethereum, deposit it in a lending protocol like Aave or Compound, and earn interest in the form of other tokens. When you are done, you unwrap and move your Bitcoin back.

The same applies to trading. If you want to trade Bitcoin for other tokens on a decentralized exchange (DEX) like Uniswap, you need to be on Ethereum or another blockchain that Uniswap supports. Bitcoin's blockchain does not have DEXs. Wrapping lets you access those markets.

Some people also wrap Bitcoin to move it between blockchains cheaply. Bitcoin transaction fees can be high, especially during busy periods. Ethereum transaction fees (called gas) fluctuate too, but sometimes moving Bitcoin via wrapping on Ethereum is cheaper than moving it directly on Bitcoin's blockchain.

The risks of holding wrapped Bitcoin

The biggest risk is custodian risk. You are trusting a company to hold your Bitcoin and not lose it, steal it, or go out of business. If the custodian is hacked and the Bitcoin is stolen, your wrapped tokens may become worthless because there is no Bitcoin backing them anymore. If the custodian goes bankrupt, you may not be able to unwrap your tokens at all. Unlike actual Bitcoin, which you can hold in your own wallet with no middleman, wrapped Bitcoin requires you to trust a third party.

A second risk is smart contract risk. Wrapped Bitcoin tokens are created and managed by code running on Ethereum or another blockchain. If that code has a bug, tokens could be created without Bitcoin backing them, or destroyed without releasing Bitcoin. This is rare but has happened — in 2020, a bug in one wrapped Bitcoin contract briefly allowed tokens to be minted without collateral.

A third risk is depegging. Wrapped Bitcoin is supposed to always be worth the same as real Bitcoin, since you can unwrap it at any time. But if the custodian becomes unreliable or people lose confidence in it, wrapped Bitcoin might trade for less than actual Bitcoin on the open market. You could sell wrapped Bitcoin at a loss, or be unable to unwrap it at all if the custodian stops processing unwraps.

Different types of wrapped Bitcoin and their custodians

WBTC (Wrapped Bitcoin) is the most common. It is issued on Ethereum by Wrapped Bitcoin, a company owned by Kyber Network, Ren, and Republic Protocol. WBTC is also available on Polygon, Avalanche, and other blockchains. The Bitcoin is held by Coinbase Custody, a regulated custodian.

renBTC is wrapped Bitcoin issued by Ren, a different company. It uses a decentralized network of nodes (called Darknodes) to hold Bitcoin instead of a single custodian. This spreads the risk across multiple parties, but it is also more complex and less widely used than WBTC.

sBTC is wrapped Bitcoin on the Stacks blockchain, which is designed to add smart contracts to Bitcoin itself. It works differently from WBTC because Stacks is more tightly integrated with Bitcoin.

Other blockchains have their own wrapped Bitcoin versions. Polygon has WBTC, Avalanche has WBTC, Arbitrum has WBTC, and so on. The underlying Bitcoin is usually held by the same custodians, but the token exists on different blockchains.

How wrapped Bitcoin differs from Bitcoin itself

Feature	Bitcoin	Wrapped Bitcoin
Blockchain	Bitcoin blockchain only	Ethereum, Polygon, Avalanche, or other blockchains
Smart contracts	Not supported	Fully supported on host blockchain
DeFi access	No DeFi protocols exist on Bitcoin	Can be used in lending, trading, and other DeFi apps
Custody	You can hold it yourself in your own wallet	Custodian holds the real Bitcoin; you hold a token
Counterparty risk	None (no middleman)	Depends entirely on the custodian
Transaction speed	10 minutes per block on average	Depends on host blockchain (seconds to minutes)
Fees to wrap/unwrap	N/A	$10 to $50 or 0.1% to 0.5% per transaction

When wrapped Bitcoin makes sense and when it does not

Wrapped Bitcoin makes sense if you want to use Bitcoin in DeFi applications, trade it on a DEX, or move it between blockchains. It also makes sense if you are already holding tokens on Ethereum and want to add Bitcoin exposure without moving money off that blockchain.

Wrapped Bitcoin does not make sense if you plan to hold Bitcoin long-term and never use it. Regular Bitcoin is safer because you eliminate custodian risk — you can hold it in your own wallet with no middleman. Wrapped Bitcoin also does not make sense if you are only making one or two transactions, because the wrapping and unwrapping fees will eat into your returns.

If you are considering wrapped Bitcoin, ask yourself: Do I need to use this Bitcoin on another blockchain, or can I accomplish what I want with regular Bitcoin? If the answer is no, stick with regular Bitcoin and avoid the fees and custodian risk.

Frequently Asked Questions

Is wrapped Bitcoin the same as Bitcoin?

No. Wrapped Bitcoin is a token that represents Bitcoin held by a custodian. You own the token, not the Bitcoin itself. The token is only valuable because the custodian promises to exchange it for real Bitcoin when you ask. If the custodian fails or loses the Bitcoin, your wrapped Bitcoin becomes worthless.

Can I lose my wrapped Bitcoin if the custodian goes out of business?

Yes. If the custodian holding the Bitcoin goes bankrupt or disappears, you may not be able to unwrap your tokens. Your wrapped Bitcoin would then be worthless because there is no Bitcoin backing it. This is why custodian reputation and security practices matter.

What happens if I send wrapped Bitcoin to a Bitcoin wallet?

Nothing useful. Wrapped Bitcoin is a token on Ethereum or another blockchain, not actual Bitcoin. Bitcoin wallets do not recognize it. If you send wrapped Bitcoin to a Bitcoin address, it will likely be lost. Always send wrapped Bitcoin to an Ethereum wallet (or whatever blockchain it is on) and send actual Bitcoin to a Bitcoin wallet.

Is wrapped Bitcoin cheaper to move than regular Bitcoin?

Sometimes. Bitcoin transaction fees vary, and Ethereum gas fees vary too. During high-traffic periods on Bitcoin, moving Bitcoin directly can be expensive. Moving wrapped Bitcoin on Ethereum might be cheaper. But you also pay fees to wrap and unwrap, so the total cost depends on how long you hold the wrapped version.

Can I make money by wrapping and unwrapping Bitcoin?

Rarely. Wrapped Bitcoin is supposed to trade at the same price as regular Bitcoin because you can unwrap it at any time. If wrapped Bitcoin trades for less, you could theoretically buy it cheap, unwrap it, and sell the Bitcoin for a profit. But this opportunity closes quickly as traders exploit it, and fees usually eat any gain.