Enter your own rate (update once a day is enough), convert USD net earnings into RMB payout, and see exactly what you receive. Fully local calculation.
Amazon settles with you in USD, but you spend in CNY. Between them sit the exchange rate and withdrawal fees (about 1%–3%). Use this tool to multiply net USD by the rate to estimate your RMB payout; subtract the withdrawal fee and that is the money you truly receive.
The rate moves daily, but updating it once at market open is enough—no need to watch it live. If you want to lock in the "earn dollars, spend yuan" exchange bonus, the key is growing your net USD profit—which brings you back to product selection and profit accounting.