First, check one thing: Is the Binance message saying "below minimum order amount" or "below minimum quantity step"? These are two different issues. The first limits your total order value. The second limits decimal places.
Let's look at the most common case first.
Case A: It says "Minimum order amount is X USDT"
This is the most direct limit. Binance sets a minimum trade amount for every spot pair. It is usually 5 USDT or the equivalent. Some coins, like BTC, have a higher minimum, sometimes up to 100 USDT.
What to do: Go to the order panel on the trading page. Look for small text next to the input box. It may say "Minimum 5 USDT" or "Min 5 USDT". Increase your amount to that number or higher.
Common mistake: Some people enter the order by quantity. For example, they try to buy 0.0001 BTC, but the order value is below 100 USDT, so it is rejected. Switch to "Amount" mode and enter the USDT amount directly. The system will calculate how much coin you can buy. That is easier.
Case B: You cannot sell your full balance, and small "dust" remains
This one is more hidden. You sell a coin and enter the full amount, but when you submit, you see a "minimum quantity step" error. Or the order fills, but a tiny leftover remains in your account and cannot be sold.
Reason: Every trading pair has a "lot size" rule. For example, the minimum quantity step for BNB/USDT is 0.001 BNB. You may have 0.12345678 BNB in your wallet. But your order can only use the number of decimal places allowed by the pair. The system does not accept the last few decimal places, so that leftover stays there and cannot be sold.
What to do: Use Binance's "Convert small balances to BNB" feature. Path: In the app or website, go to Wallet → Spot → find "Small Balances" or "Convert Small Balance". The system will automatically convert those dust amounts below the minimum trade size into BNB.
Case C: Trying to sell a large order worth hundreds of thousands of USDT?
If you want to manually sell a large spot amount of 200,000 USDT or more, normal order methods may not apply. Binance Spot OTC (quote trading) has a minimum trade size of 200,000 USDT. Below that amount, a normal market or limit order is fine. There is no extra minimum size limit.
Where to check the exact minimums for a trading pair
Do not guess. Look it up directly.
Web: Open the spot trading page. Find the "Settings" icon (the gear) in the top right corner → click "Trading Parameters". The popup will list the "Minimum Trade Amount", "Minimum Quantity Step", and "Minimum Price Movement" for that pair.
App: Open the spot trading page. Tap "..." in the top right corner → "Trading Parameters".
Risk reminder: Do not force a bigger order just to pass the minimum
Some people see the "below minimum amount" message and add extra money to pass it. If you are only testing or making a small regular buy, do not force it. Wait until you have enough to meet the minimum before placing an order, and save on fees. Also, be careful with market orders when you add extra money. If slippage goes beyond your tolerance, your order may be partially filled, and the rest will be cancelled.
How to verify after you place an order
After the order is submitted, go to Orders → Order History and check the status. If it says "Filled", the order passed the minimum requirement. If it says "Cancelled" and the reason is "LOT_SIZE" or "MIN_NOTIONAL", it did not meet the minimum order amount or decimal place rule. Go back and place a new order.
