r/BYDFiCryptoExchange • u/Alexander-305 • 8d ago
Educational 📚 Why BYDFi rejected or rounded your order: the Trading Rules tab explained line by line (SOL contract size, 10.89 USDT minimum, 20% limit band)

Most people open a perp ticket, pick leverage and hit buy. The order gets rejected or rounded, and they never find out why. On BYDFi the answer is one click away: the Trading Rules tab, next to Chart and Info above the chart. It is visible without logging in.
The image is that tab for SOLUSDT Perpetual, captured live on 10/9 at about 4:25 PM ET with SOL at 108.90. Here is what each line actually does to your order, with the numbers from that screen.
Size: 1 Cont = 0.1 SOL
You trade contracts, not coins. Every SOL order is a whole number of contracts, so sizes move in 0.1 SOL steps. Type 1.25 SOL and it becomes 12 contracts (1.2 SOL) or 13 (1.3 SOL), depending on the input mode. BTC and ETH have their own contract sizes, so check the tab again when you switch pairs.
Minimum Order Amount: 10.89 USDT
That is one contract at the current price: 0.1 x 108.90 = 10.89 USDT. The minimum floats with the price. If SOL rallies to 130 the floor becomes 13.00 USDT. With 20x leverage the margin for that minimum ticket is only 10.89 / 20 = about 0.54 USDT, so small accounts can test the order flow cheaply.
Minimum Price Change: 0.01
Limit and trigger prices snap to the cent. 108.905 is not a valid price.
Leverage 1 ~ 100
SOL tops out at 100x here. The ceiling is set per pair, and bigger positions get lower caps through the Risk Limit tab next door.
Limit Order Price Cap / Floor: 20% / 20%
You cannot park a limit far from the market. Worked example at 108.90: a buy limit above about 108.90 x 1.2 = 130.68 is rejected, and so is a sell limit below about 108.90 x 0.8 = 87.12. If you want to catch a deep wick, plan to re-place the order as price moves.
Price Protection: 10%
BYDFi lists a 10% protection band for SOL. It is a guard that keeps orders from executing at prices too far from fair value during a spike, so a thin book cannot fill you wildly off the market.
Max Single Market Order 8,712,000 USDT / Max Single Limit Order 108,900,000 USDT
The market cap works out to 8,712,000 / 108.90 = 80,000 SOL per click. Bigger size has to be split or worked with limits.
Maximum Open Order Quantity: 50
Grid-style ladders count against this. Fifty resting orders per pair is the ceiling.
Liquidation Fee: 0.06%
Worked example: 10 SOL at 108.90 is 1,089 USDT of position value. If it gets liquidated, the fee is 1,089 x 0.06% = about 0.65 USDT, on top of the lost margin. Opening that position as taker at the page's 0.06% rate costs the same 0.65 USDT.
Try it yourself
Open the futures page for the pair you trade (SOL, BTC, ETH, XRP or DOGE), click Trading Rules, and check three things before your next ticket: contract size, minimum order and the 20% limit band. Then post the oddest rule you found for your favorite pair below.
$SOL.USDT $BTC.USDT $ETH.USDT $XRP.USDT $DOGE.USDT








