# UART Baud Rate Error > From the peripheral clock and target baud get the divisor, actual baud and error % — and find out whether your UART really communicates or fails on frames. Practice: elettronica Status: Proto v0.1 Tag: UART, Baud rate, Serial, MCU, Clock Method, assumptions and limits: Page: --- Tool to check a UART configuration. Enter the peripheral clock, desired baud, oversampling (8/16×) and optional fractional divisor: get the divisor, the actually generated baud, the percentage error against target, and a table of all standard bauds at that clock. Beyond ±2-3% error the link starts dropping frames. This file is a **descriptor**, not the tool's documentation: it says what the tool computes and by what method, in summary. Formulas, assumptions, validity conditions and limits are in the wiki linked above. The tool runs in the browser at the page given.