Orders and the order book: market, limit, spread and slippage
After this lesson you can read an order book, choose between a market and a limit order, and calculate the spread and slippage before you click.
Orders aur order book: market, limit, spread aur slippage
Order book ki do taraf hoti hain: bids yani khareedar, aur asks yani bechne wale. Sab se oonchi bid aur sab se neechi ask ke darmiyan farq ko spread kehte hain. Har price par kitna maal intezar mein hai, usay depth kehte hain. Screen par jo price hai woh aakhri sauda hai, zaroori nahi ke aap ko wohi price mile.
Market order foran fill hota hai lekin spread deta hai, aur agar order pehle level se bara ho to book mein upar chadhta jata hai. Isay slippage kehte hain. Faisal ki misal: $0.500 dekh kar 1,000 USDT ka market buy kiya, average $0.5213 aaya, yani 4.3% mehnga. Foran wapas bechta to taqreeban 6% nuqsan hota, sirf do click mein.
Limit order mein price aap khud tay karte hain, bas yeh zaroori nahi ke order fill ho. Patle coins mein hamesha limit order istemal karein aur pehle depth dekhein. Islam mein qeemat ka maloom hona aur bahami raza zaroori hai (Quran 4:29), aur book mein jhootay orders laga kar doosron ko dhoka dena usi dhoke mein aata hai jis se mana kiya gaya hai.
- Spread sab se achay khareedar aur sab se achay bechne wale ka farq hai, aur har market order yeh deta hai.
- Jab order book ke pehle level se bara ho to slippage aati hai.
- Patle market mein limit order lagayein, pehle depth dekhein, aur green candle ke peeche market buy mat karein.
Poora sabaq neeche English mein hai. Quiz English mein hai; asaan alfaaz mein.
Faisal runs a mobile repair counter in Multan and has been watching a small coin for a week. The app shows $0.500. He decides to buy 1,000 USDT worth, taps Market Buy, and the order fills in one second. When he checks, his average price is $0.521, not $0.500, and the coin now shows $0.550. He is sure the app cheated him. It did not. He simply did not know that the price on the screen is not the price he would get.
Reading the book
An order book lists everyone waiting to trade. Bids are buyers and the prices they will pay; asks are sellers and the prices they want. The highest bid and the lowest ask meet in the middle, and the gap between them is the spread. The quantity waiting at each price is the depth. A deep book has large quantities close to the price; a thin book has small quantities with big gaps between levels.
Market orders and limit orders
A market order says 'fill me now at whatever prices are available'. It always fills, but it pays the spread and walks through the book if it is larger than the first level. A limit order says 'only at this price or better'. You control the price, but it may not fill at all. Limit orders often pay a lower fee, because they add depth to the book instead of taking it.
- Market order: speed over price. Fine for small orders in deep markets.
- Limit order: price over speed. Use it for thin coins and most planned entries.
- Stop-limit on spot: an exit order that triggers at a level you set in advance.
Slippage: when your order is bigger than the first level
Slippage is the difference between the price you expected and the average price you got. It comes from walking the book: your order eats the first level, then the next, then the next, each more expensive. In Bitcoin a $1,000 order barely touches the first level. In a small coin the same order can climb several levels. Before any market order, compare your order size with the quantity waiting at the best two or three prices.
Faisal's 1,000 USDT market buy, level by level
Best bid $0.490, best ask $0.500. Spread: $0.010, about 2% of the price. Compare Bitcoin at a bid of $60,000.00 and an ask of $60,000.10: a spread of about 0.0002%.
Sellers waiting: 400 coins at $0.500 ($200), 500 at $0.510 ($255), 600 at $0.525 ($315), and 1,000 at $0.550. His order takes the first three levels for $770 and 1,500 coins, then spends the last $230 at $0.550 for 418.18 coins. Total: 1,918.18 coins for $1,000, an average of $0.5213.
Slippage: 4.3% worse than the $0.500 on screen. If he sold straight back into the $0.490 bid, even if it could absorb everything, he would get about $940: a 6% loss from two clicks, before fees.
Islamic sale needs a known price and free consent (Quran 4:29). An order book fits this well: each fill is a separate sale at a price visible when it happens. A limit order gives you full control over that price. A market order means you accept the best prices available at that moment, so check the depth first and nothing will surprise you. The Prophet (peace be upon him) forbade the gharar sale (Sahih Muslim 1513), and scholars apply the same spirit to deception inside the book, such as fake orders placed to scare others or trading with yourself to fake volume.
Education, not a fatwa. Where scholars differ, we say so. See what scholars say.
Market-buying a thin coin in excitement. The screen shows the last traded price, not the price you will get. On a coin with a 2% spread and a thin book, a market buy followed later by a market sell can cost 5% to 10% before the price has moved at all. Use limit orders outside the largest markets, and look at the depth first.
Open the Ethereum 4-hour chart with key levels. Pick the nearest key level below the current price and write it down as the limit price you would use instead of a market order. Then open the order book on your exchange for ETH and for one small coin, without trading, and note the best bid, best ask and spread % for each, plus how many dollars wait at the first five ask levels.
Find a limit level →Key takeaways
- The spread is the gap between the best buyer and the best seller, and every market order pays it.
- Slippage appears when your order is bigger than the first level of the book.
- In thin markets use limit orders, check depth before you click, and never chase a green candle with a market buy.
Check yourself
Pass with 2 of 3 to complete the lesson. Answers are checked on our server, so the certificate means something.
Barqish is an educational platform. Nothing here is financial advice or an instruction to buy or sell, and screening is not a fatwa. Spot ownership only: no leverage, no short selling. Updated 30 September 2026.