A market order prioritises execution against available orders. A limit order sets the worst price you are willing to accept, but may wait or remain unfilled. On BTC/ZAR, the useful choice depends on how much you need to trade, how much liquidity is visible and whether waiting is acceptable.
Neither order type guarantees a favourable future price. A limit order can also pay a taker fee if it immediately matches existing liquidity. Check the execution and fee classification rather than assuming “limit” means “maker”.
Read the order book as quantities at prices
Imagine these hypothetical sell offers. They are teaching inputs, not a screenshot or live market observation.
| BTC offered | Rand price per BTC | Rand value |
|---|---|---|
| 0.002 | R1,800,000 | R3,600 |
| 0.003 | R1,810,000 | R5,430 |
| 0.005 | R1,825,000 | R9,125 |
A market purchase for 0.005 BTC takes the first two rows, assuming they remain available. Its pre-fee cost is R3,600 + R5,430 = R9,030. Average price is R9,030 ÷ 0.005 = R1,806,000 per BTC. Multiplying the entire amount by the first visible price would give R9,000 and understate the cost by R30.
The difference is caused by consuming more than one price level. It is not automatically an extra fee charged by the exchange. Real orders can change while you are confirming.
Add the correct fee without changing the example
At VALR's checked entry-tier fiat taker rate of 0.35%, a fee on R9,030 trade value is R31.605, displayed here as R31.61. If charged additionally in rand, total debit would be R9,061.61. If the fee is deducted in BTC or reserved within a budget, the final quantity or usable spend changes instead. Read the actual fee currency and confirmation.
Luno's entry-tier BTC/ZAR taker rate is 0.60%. Applying it to the same hypothetical trade value gives R54.18. These calculations isolate fees on identical assumed fills. They do not claim both venues offer the same book or that one will deliver the better live price.
What a limit changes
A buy limit of R1,805,000 per BTC cannot take the second row at R1,810,000 under the stated limit. It could fill 0.002 BTC at the first row and leave 0.003 BTC open, depending on the order's time-in-force and platform behaviour. The limit controls the acceptable price; it does not ensure the whole amount trades.
A limit above the available offers could execute immediately and remove liquidity. A posted order below the current offers may add liquidity but needs another participant to trade against it. Before using a post-only or time-in-force option, read the provider's specific definition and rejection/cancellation rules.
Manage partial fills deliberately
After placing an order, inspect filled quantity, average fill price, fees and remaining quantity. Cancelling an unfilled remainder does not undo completed fills. If you then submit a new order for the original full quantity, you may buy more BTC than intended.
For example, your target is 0.005 BTC and 0.002 BTC has filled. The remaining target is 0.003 BTC before considering fee deductions. Keep the filled amount in your calculation when changing strategy.
Use a simple order log with target quantity, order ID, limit, filled quantity, remaining quantity and cancellation confirmation. This is especially useful when a mobile notification arrives after you have already opened a second screen.
Choose by the constraint that matters
Use a market order only when you accept the available execution and have checked the size relative to liquidity. Use a limit when price control matters more than immediate completion, with a plan for an unfilled remainder. Neither choice requires derivatives or leverage.
For a fixed monthly rand budget, reserve room for fees instead of treating the whole bank balance as trade value. For a cash-out needed by a deadline, remember that completing the trade is only one stage before bank withdrawal.
The Bitcoin buying guide covers the broader purchase flow, and the exchange hub helps compare venues. Practise the arithmetic on a hypothetical order book before using an amount whose execution you cannot easily check.
Sources and verification
Primary sources checked on 20 September 2026. Prices, availability and processing arrangements can change.