fees calculator

hi there, how can i make fees calculator like it is in the link?

https://www.infoabsolute.com/venmo-goods-service-fee-calculator/

https://num1blog.com/2022/07/27/venmo-fee-calculator-2022-venmo-seller-fee-for-goods-and-service/

Transaction fee = $0.10 + 1.9% of the total buyer’s payment.

The seller’s transaction fee for Goods & Services is 1.9% + $0.10.
For example, if the buyer pays $100.00, the transaction fee is $2.00. And, the seller will receive $100.00 – $2.00 = $98.00. And, $2 is a seller fee.

$2.00 as a seller transaction fee.

Thanks

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