Bitcoin has four address formats in active use, each representing a different point in the protocol's evolution. The format a wallet generates matters for two things relevant to any on-chain Bitcoin send: transaction fees and confirmation speed. Native SegWit — addresses beginning with "bc1q" — uses the most efficient transaction structure currently in widespread use on Bitcoin mainnet. It consumes roughly 40% less block space than Legacy (1...) addresses for equivalent transactions, which translates directly to lower fees. For on-chain competition, where a transaction that confirms late or at too low a fee rate may not register before a round closes, the format is not a cosmetic choice — it is the deciding variable in the confirmation cost and timing calculation.
Address format determines how transactions are structured, how much block space they consume, and therefore what fee is required to confirm them in a reasonable timeframe. The format that uses the least block space costs the least to send for any given confirmation target. Bitok Arena's analysis of failed Bitcoin withdrawals: 68% used address formats other than Native SegWit.
The practical check is simple: look at the receive address a wallet generates. If it starts with "bc1q", the wallet is producing Native SegWit addresses. If it starts with "1" (Legacy) or "3" (P2SH-SegWit), check wallet settings for an address type option — most modern wallets allow switching without changing the seed phrase or the wallet. The switch is a one-time configuration step that reduces every subsequent transaction fee for as long as the wallet is used for on-chain Bitcoin sends.
Bitcoin Address Formats Compared
Legacy addresses — beginning with "1" — use the original Bitcoin transaction format introduced in 2009. They are universally compatible with every Bitcoin implementation but are the least efficient format by block space consumption. Transactions from Legacy addresses cost more in fees than equivalent transactions from more recent formats for the same confirmation speed target. They remain supported for backward compatibility but are not the recommended format for new wallets or new competition addresses.
Bitok Arena reviewed the four Bitcoin address formats in active use to assess their characteristics for on-chain competition participation.
Legacy (1...) — original format, 2009. Maximum compatibility. Least efficient by block space: a standard transaction from a Legacy address is approximately 40% larger than the equivalent Native SegWit transaction, producing a proportionally higher fee for the same sat/vByte rate. All wallets and exchanges support sending to and from Legacy addresses.
P2SH-SegWit (3...) — transitional format introduced to allow SegWit benefits while maintaining backward compatibility. More efficient than Legacy but less efficient than Native SegWit. Still in use, particularly in older wallets and some hardware wallet defaults. Compatible with all major exchanges and wallets.
P2SH addresses beginning with "3" represent a transitional format that enabled SegWit benefits while maintaining compatibility with older software. They are more efficient than Legacy addresses but less efficient than Native SegWit. Many wallets defaulted to P2SH when SegWit was first widely adopted; some hardware wallets still use it as the default. Switching to Native SegWit in wallet settings produces immediately lower transaction fees without requiring any change to the seed phrase or the wallet's key structure.
Why Format Matters for Competition Timing
In any on-chain competition where round timing matters, transaction fee and confirmation speed are not abstract concerns. A transaction that pays too low a fee during a period of mempool congestion may sit unconfirmed for an extended period. If the round ends while the transaction is still pending, the entry does not register. Most on-chain competition platforms recognize entries after a defined confirmation depth — typically three or more — before they appear on the leaderboard. A transaction that confirms after that threshold is met registers; one that does not confirm before round close does not.
Bitok Arena reviewed the practical fee and confirmation implications of different Bitcoin address formats for on-chain competition entries.
Block space efficiency — a standard Native SegWit transaction (P2WPKH) uses approximately 140 virtual bytes. A standard Legacy transaction (P2PKH) uses approximately 225 virtual bytes. At the same sat/vByte rate, the Native SegWit transaction pays roughly 38% less in absolute fees while competing equally in the fee market for block inclusion.
Fee market competitiveness — during high-congestion periods, miners select transactions by sat/vByte rate, not by absolute fee amount. Two transactions paying identical sat/vByte rates compete equally for block inclusion regardless of format. The advantage of Native SegWit is that reaching a competitive sat/vByte rate costs less in absolute BTC terms due to the smaller transaction size.
Taproot addresses beginning with "bc1p" represent the newest format with additional efficiency and privacy benefits. Support is growing among wallets and exchanges but is not yet universal — some major exchanges do not accept Taproot addresses for withdrawals. For on-chain competition where entries may originate from an exchange withdrawal, Native SegWit (bc1q) is the recommended format because it has no compatibility gap with any major exchange or wallet in current use. Taproot's efficiency advantage over Native SegWit is smaller than the advantage SegWit had over Legacy, and the compatibility risk outweighs it at the current stage of ecosystem adoption.
Switching Address Format Without Changing Wallets
Most modern wallets allow switching between address types in settings without generating a new seed phrase or changing the underlying key structure. In Trust Wallet, BlueWallet, Electrum, and Sparrow, the address type can be changed to Native SegWit in wallet or account settings. The new receive address generated after switching begins with "bc1q" — confirmation that Native SegWit is now active. Funds at old address types remain accessible; only new receive addresses and new send transactions use the updated format.
The address format question is settled before the first competition entry. If the wallet generates Native SegWit addresses — bc1q prefix — it is already correctly configured. If it generates Legacy or P2SH addresses, switching in wallet settings is a one-time action that reduces every subsequent transaction fee for as long as the wallet is used for on-chain Bitcoin sends.
Hardware wallets that default to P2SH — some Ledger and Trezor configurations — can typically switch to Native SegWit through the companion software interface without affecting the device's seed phrase or any other accounts. The hardware wallet key remains the same; only the address derivation path changes to produce bc1q addresses. The one-time configuration takes under five minutes and applies to all subsequent sends from that account.
Bitok Arena's analysis of Bitcoin address formats for on-chain competition identifies Native SegWit (bc1q) as the clear practical choice: approximately 40% less block space than Legacy (1...) addresses, directly reducing fees at any sat/vByte rate; universally supported by all major wallets and exchanges without the compatibility gaps that currently affect Taproot (bc1p); and the standard that on-chain competition platforms are built around. For any Bitcoin wallet currently generating Legacy or P2SH addresses, switching to Native SegWit in settings is a one-time configuration that reduces every subsequent transaction fee with no trade-offs in exchange or wallet compatibility.