Order-Book Depth Compared: Why the Same Big Order Costs Some People 0.3% More

Bottom line first: Trading fees are out in the open; slippage is in the dark. The same $50,000 market order might cost only 0.01% more in a deep market, or 0.3% more in a thin one — that's tens to hundreds of dollars in one go, while a fee difference of a few dollars takes a whole year to add up.

Measured depth snapshot (snapshot date 2026-10-12, BTC/USDT)

Exchange	Depth within 1% (both sides combined)	Bid-ask spread
Binance	≈ $16.03M	0.00 bps
Bybit	≈ $4.84M	0.01 bps

• Depth is the total notional of all resting orders within 1% of the mid price — it determines "how much you can fill before the price moves noticeably."
• The spread is the distance between best bid and best ask; smaller is better.

How we estimate slippage (methodology public)

Slippage ≈ spread/2 + (your order size ÷ depth on that side) × 10 bps coefficient

This is an estimate, not a measured execution-price difference. Real slippage also depends on how you place the order (market/limit), the instantaneous liquidity at the moment you send it, and how you split the order.

Why we mark three exchanges' depth as "not collected"

Only Binance's and Bybit's order-book snapshots come in reliably through the current collection pipeline (public APIs). OKX / Gate / Bitget's depth data is not connected yet, and we won't fill "close enough" numbers into the comparison table — in the ranking their corresponding dimensions show as missing and are treated as a neutral score (and the page says plainly that this "should not be read as an overall lead").

Practical conclusions

• Any order larger than 1% of the depth on that side must be split or switched to a limit order, otherwise the slippage will exceed the trading fee you saved.
• Long-tail-coin traders especially: good depth on the majors doesn't mean the coin you're trading has good depth, each specific coin has to be checked on its own.
• However low the fee, a single bad fill can wipe it out.

Next steps

• The total cost calculator lists slippage as its own line item, so you can see its share of total cost
• For the full picture of each exchange's fees: five-exchange annual cost comparison

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Data source and fetch time: Binance /api/v3/depth?symbol=BTCUSDT&limit=500, Bybit /v5/market/orderbook (public APIs, fetched 2026-10-12T13:47:06Z). Snapshot date 2026-10-12.

Disclaimer: Depth changes by the second with the market; the table above is only a snapshot; this site is not investment advice.