Payment Amount Precision

Overview

What it means

Payment amount precision describes how many decimal places a payment system can represent accurately for a currency or token. Incorrect precision can cause a customer to pay a different amount from what the merchant intended.

How it works

Every token has a smallest unit specified by its protocol or token contract. Amounts should be represented as integer base units or decimal types with explicit scale, not ordinary binary floating-point values. Checkout rounding and accepted tolerances must be consistent across price quotes, invoice storage, token transfer parsing and accounting.

Understanding the technical details

A robust pricing engine chooses one canonical numeric scale at the point of invoice creation and preserves raw base units all the way through reconciliation. For example, six-decimal tokens require multiplying the displayed amount by one million to produce integer units. Never compare a floating-point USD quotation directly with a token balance as if they share precision. Define whether rounding occurs before or after fees and whether tiny residuals are refundable or carried forward.

Common failures and limitations

Using the wrong token decimals can multiply an amount by factors of ten. Small rounding discrepancies can also trigger false underpayments if checkout, payment monitor and ledger calculate differently. Exchange-rate conversion adds another independent rounding decision.

Related concepts

Crypto Invoice, Crypto Checkout, Crypto Payment Link.

Further reading

OxaPay — Integration documentation.