When paying a BitPay invoice you will need to pay the necessary miner fee in order for your transaction to be processed on the cryptocurrency network.
A network cost may also apply to your purchase depending on the cryptocurrency you use.
These fees will vary depending on the conditions on the cryptocurrency network - the higher the demand, the higher the fees will be.
This article gives an overview of the fees applicable for each cryptocurrency supported as payment option on the BitPay invoice:
Bitcoin (BTC) & Bitcoin Cash (BCH)
Payment Protocol payments require that you send an appropriate miner fee with your payment. Miner fees are given to the miner that adds the transaction to the blockchain. These miner fees are not BitPay fees. A higher miner fee increases the likelihood that your transaction will confirm more quickly.
A simple way to ensure that any transaction includes an appropriate fee is to adjust your wallet settings to include a dynamically-calculated fee. The BitPay Wallet includes this setting option, which will help ensure that your transaction confirms even during high network traffic.
When you pay a BitPay invoice, your payment goes to a BitPay address. We pay network-based miner fees (just like you pay to send BTC or BCH) to move invoice payments to combine them for processing. This is called a "UTXO sweep" (Unspent Transaction Output sweep). BitPay uses the Network Cost fee for the UTXO sweep, so it is not returned with refunds.
Miner fees are variable costs for BitPay based on network conditions. This means the Network Cost fee also changes to reflect network conditions. Read our original post about why we introduced the Network Cost in February 2017.
Refund Miner Fee Cost
If you underpay or overpay a BitPay invoice and initiate a refund, BitPay will deduct the miner fee cost of returning the payment from the total refund amount you receive.
If a BitPay merchant issues a full refund to a customer, BitPay will deduct the miner fee amount from the merchant’s ledger balance. The deduction will be a separate entry in the merchant’s BitPay ledger after we process the refund. The purchaser will receive the full amount of the refund requested.
Gas (or “gas fee”) is the cost in gwei associated with each operation required to complete Ethereum transactions. Gas fees are estimated based on network congestion of the most recent block. Gas fees are similar to bitcoin miner fees. The gas fee equals the gas price multiplied by the gas limit (gas fee = price * limit).
Your gas limit is the maximum amount (in units of gas) you are willing to spend to complete the transaction.
The gas price is the amount you are willing to spend on each unit of gas (in gwei). You can speed up a transaction by choosing a higher gas price before sending.
USD Stable coins (ERC20 tokens)
To pay a BitPay invoice using ERC20 tokens (stable coins), you will need an ETH balance. This is because ERC20 transactions require gas to make payments. ERC20 tokens use the ETH blockchain. You will need gas both to interact with the smart contract and to send the payment to the invoice (two transactions).