Info
A P2WPKH enter weighs 68 vB (assuming the worst-case with a high-r signature, -0.25 vB with a low-r signature) and a P2WPKH output weighs 31 vB for a complete of 99 vB.
A P2TR enter weighs 57.5 vB and the output weighs 43 vB for a complete of 100.5 vB.
P2WPKH is cheaper if you pay your self as typically as you spend inputs
P2TR is about 1.5% dearer throughout the lifecycle! Does that imply that I ought to proceed utilizing P2WPKH?
Sure, if nearly your whole transactions have a single enter and create change, you would certainly save a tiny portion of charges through the use of P2WPKH.
The under desk reveals the entire weight of transactions underneath the idea that almost all of them are single-input and creating change, created utilizing both P2TR or P2WPKH outputs, and one among X transactions having a two inputs as an alternative of 1:
If just one out of seven transactions makes use of two inputs and also you all the time create change, you’ll have the ability to save as much as 1.5% by sticking to P2WPKH.
If 1 out of 6 transactions has a minimum of two inputs or if you happen to can typically keep away from creating change, your whole transaction weight would find yourself being decrease if you happen to use P2TR.
More often than not, others are paying you, and often the sender pays for the output (otherwise you pay a flat charge to withdraw no matter output sort). Each time others pay you, you solely pay for the enter. P2TR inputs are 15% cheaper than P2WPKH inputs (57.5 vB vs 68 vB). Sure, which means externalizing the associated fee on the sender, however the senders don’t get a say in how the recipient needs to receives a commission, and senders usually appear effective with paying for a P2WSH output (which prices the identical as P2TR).
Batching
Everytime you use extra inputs than you ship outputs to your self (e.g. if you make huge transactions for batching funds, consolidation transactions, the funds you obtain are smaller than those you make), otherwise you’re capable of keep away from change altogether, it will likely be cheaper to make use of P2TR:
Consumer eventualities
Hardly any pockets operator’s spending sample would ever match the idea that almost all transactions have just one enter and create change. Let’s contemplate a number of person eventualities.
Hodler
If you happen to often DCA, you should have many small-value UTXOs. You could sometimes sweep them into chilly storage, or in any other case consolidate some. Then, or every time else that you simply do create a transaction, it is going to probably have a number of inputs. If you happen to purchase larger quantities directly, you should still maintain your UTXOs for an unknown period of time, and it’s unattainable to know now what the feerates might be like if you truly need to spend the UTXOs. If you happen to time your UTXO administration transactions to low feerates, you’ll most likely create most of your self-sent outputs at decrease feerates than the eventual spend. In both case, you’ll create fewer change outputs than inputs, and it advantages you to have lighter inputs everytime you do resolve to spend.
Pay as typically as you obtain
It’s not clear who would have such a spending sample, however let’s say you obtain funds precisely as typically as you make them and each cost creates change. In that case, solely about half of the UTXOs you obtain had been despatched to you by your self. Clearly, within the long-term you’ll spend about twice as many inputs as you create change outputs. It can due to this fact be cheaper to make use of P2TR.
Client in a round Bitcoin economic system
An exception may be a person that lives within the Bitcoin round economic system. You get your wage in bitcoin a few times a month and peel all of your funds off from that over the remainder of the time (let’s ignore the privateness implications for a second). On this case, you would possibly create change 6× as typically because the variety of instances that you’ve a second enter. Assuming this sample, you’d have the ability to save as much as 1.5% through the use of P2WPKH as an alternative of P2TR.
Service provider/Service
If you happen to provide a service or are a service provider, you’ll obtain many smallish funds or deposits, and sometimes will make bigger funds to cowl prices or pay suppliers. Everytime you receives a commission, your clients can pay to your recipient output, however you solely pay for the inputs. While you make your bigger funds, you might be prone to have two or extra inputs. P2TR inputs are 15% cheaper than P2WPKH inputs (57.5 vB vs 68 vB). You could sometimes consolidate many low-value UTXOs at opportune mempool circumstances. Usually, your depend of inputs will closely outweigh your depend of change outputs. It follows that it’s cheaper so that you can use P2TR.
Trade/Brokerage
If you happen to give out P2TR deposit addresses, your clients pay for the bigger outputs, and you’ve got much less price if you spend these deposits. Most exchanges and brokerages batch withdrawals. Batched cost transactions will typically have a number of inputs, however solely require a single change output to facilitate many withdrawals. While you consolidate leftover small inputs, you achieve this at opportune moments with low feerates, and the various smaller inputs simply outweigh the creation of 1 heavier output in your consolidation transaction. While you do must make a transaction at a excessive feerate sometimes, it serves you properly that your inputs are cheaper. P2TR is unquestionably cheaper for you than P2WPKH.
Multi-wallet setup with spend-only pockets
One other exception could be, if you happen to facilitate a high-volume of funds per a multi-wallet setup that features a “spend-only pockets”. You’ll sometimes prime up that pockets with massive UTXOs from which you peel off funds. In that case, I might see the way you would possibly truly find yourself with creating change 6× as typically because the variety of instances that you’ve a second enter. In that case, you’d have the ability to save as much as 1.5% through the use of P2WPKH as an alternative of P2TR for the spend-only pockets. When you have a very huge operation, that may use each P2WPKH and P2TR, you would probably save a bit extra by preferring P2TR inputs and P2WPKH change outputs at excessive feerates, whereas preferring P2WPKH inputs and P2TR change outputs at low feerates. If you happen to do find yourself having extra inputs than change outputs, you need to have picked P2TR within the first place.
Conclusion: P2TR is cheaper in nearly each state of affairs
Whereas it’s cheap to attend with switching whereas particularly exchanges are nonetheless dragging their ft to allow help for sending to P2TR outputs, simply from a value perspective, P2TR finally ends up being cheaper in nearly each state of affairs. Moreover, if it is advisable to create transactions at excessive feerates sometimes, the lower-weight inputs will save price. General, you’d save as much as 15.4% in transaction charges through the use of P2TR as an alternative of P2WPKH. If you happen to make vastly extra small funds than you obtain funds, chances are you’ll save as much as 1.5% by sticking to P2WPKH.
