Are Zero-Fee Exchanges Really Cheaper? The Three Parts of Trading Costs: Fees, Spread and Slippage

“Zero fees” sounds like the cheapest option, but the fee is only one part of what a trade costs. When you buy crypto with a market order, you actually pay three things: fees, spread and slippage. Taking the fee to zero doesn’t make the other two go away.

The short version: for small trades on pairs with enough depth, zero fees usually do save money; but once the order gets large and the pair’s order book is thin, slippage can cost more than the fees you save. Below I use a simplified method to estimate slippage from each exchange’s published ±2% order book depth: estimated slippage ≈ order size ÷ depth × 1%. By this method, once an order reaches one tenth of the depth, estimated slippage is about 0.1%, the same as a 0.1% fee.

The three parts of trading costs: fees, spread and slippage

All three are percentages of the trade value, so you can add them up and compare them directly. Measured from the mid price (the average of the highest bid and lowest ask), the cost of one market buy is roughly:

Trading cost ≈ fee rate + half the spread + slippage

For a round trip (buying and then selling), you pay the fee twice, the full spread once, and slippage twice.

Fees: how maker and taker work

• Maker: a limit order that doesn’t fill immediately and sits in the order book waiting for someone to trade against it.
• Taker: an order that trades directly against existing orders, such as a market order.

At most exchanges taker fees are higher than maker fees, and market orders pay the taker rate. The table below shows each exchange’s official rates for regular users (VIP 0), plus the effective taker rate after the fee discount you get with an invitation code:

Data checked: 2026-10-08

A few exchanges in the table charge 0% or close to 0% on spot, which is what people mean by “zero fees”:

• Bitfinex: its official zero fees Q&A states that from 17 December 2025, maker and taker fees are 0% on spot, margin, derivatives and other trading; lending fees are unchanged, and withdrawal and other fees still apply (checked 12 October 2026).
• MEXC: its official announcement of 22 December 2025 introduced zero fees on all spot pairs with no set end date; institutional accounts, market makers, project teams and API users are excluded (checked 12 October 2026). The official rates this site checked on 8 October 2026 are in the table above. Rates during the promotion may differ from the usual ones; what each pair’s order page shows is what counts.
• Ourbit: its spot fees and the list of pairs that “stay at 0” are in the Ourbit Review.

How to compare fees, VIP thresholds and platform token discounts is covered in the International Crypto Exchange Fee Comparison; how the invitation code fee discount is calculated is in What Is a Crypto Exchange Fee Discount?.

Spread: the gap between the bid and the ask

An order book always has two prices: the highest price someone is willing to pay (the best bid) and the lowest price someone is willing to sell at (the best ask). The difference between them is the spread (bid-ask spread).

A hypothetical example: best bid 100.00, best ask 100.05, mid price 100.025.

• A market buy fills at 100.05, about 0.025% above the mid price, which is half the spread.
• Sell immediately with a market order and it fills at 100.00. Before fees, the round trip loses 0.05%, exactly one full spread.

The spread has nothing to do with fees; zero-fee exchanges charge it too. On large exchanges, the spread on popular pairs such as BTC/USDT is usually tiny; on less popular coins, newly listed coins or low-volume exchanges, it can be much wider. A glance at the best bid and best ask before you trade tells you how wide it is.

Slippage: large market orders eat through several price levels

Slippage happens when an order is too big for the first price level, so the rest fills against orders at worse prices further back, and the average fill price for the whole order ends up worse than the price on screen. The bigger the order and the thinner the order book, the larger the slippage.

I worked through one real order book in Bitfinex USDT to USD: on 8 October 2026 the last USDT/USD trade was at 1.0012, and a market sell of 100,000 USDT would have filled at an average of about 1.0011, about US$10 less than at 1.0012. Bitfinex’s trading fee is 0%, so those US$10 are the cost of the spread plus slippage.

Estimating the real cost of zero fees from order book depth: 10,000 and 100,000 USDT

The most direct way to compare slippage across exchanges is to look at order book depth: how much is actually on offer in buy and sell orders within 2% above and below the price. The table below shows each exchange’s ±2% depth for BTC/USDT and ETH/USDT. The data comes from CoinGecko, and each figure is the average of the +2% sell orders and the −2% buy orders, so you can treat it as the order value on one side:

Data checked: 2026-10-08

The estimate: assume orders are evenly spread

I use the simplest assumption: sell orders are evenly spread between the mid price and 2% above it, with a total value equal to the depth D in the table. When you market buy Q USDT:

1. By the time you’ve bought up to p above the mid price, you’ve eaten D × p ÷ 2% of the sell orders, so once Q is filled the furthest price reached is p = 2% × Q ÷ D.
2. Because orders are evenly spread, the average fill price sits roughly halfway between the mid price and that furthest price, p ÷ 2 away from the mid price.

Estimated slippage ≈ order size ÷ depth × 1%

I chose this method because it uses just one number from the table, so anyone can plug it in and check. What it gives is the deviation from the mid price, which already roughly includes half the spread.

Know its limits before you use it:

• It only works when the order is clearly smaller than the depth: once the order approaches or exceeds the depth, it goes beyond the ±2% range and the method no longer applies.
• It may overestimate for major pairs: real orders often cluster near the mid price, so slippage on small orders may be smaller than the estimate.
• It may also underestimate: depth is a snapshot at one moment, orders get pulled when the market moves sharply, and depth aggregated by third parties can be inaccurate.
• This is BTC and ETH depth: other coins usually have much thinner books, so check the order page for that pair yourself.

Data checked: 2026-10-08

Rough slippage = order size ÷ ±2% order book depth × 1% (assumes orders are spread evenly within ±2%; an estimate, not a quote)

Worked example: estimated slippage on 10,000 and 100,000 USDT at different depths

The table below uses three hypothetical depths (not figures for any particular exchange). Amounts are in USDT:

Now compare that with fees. At a 0.1% taker rate, 10,000 USDT pays 10 USDT and 100,000 USDT pays 100 USDT:

• Depth of US$20 million: estimated slippage on 100,000 USDT is only one twentieth of the fee, so you’re comparing almost nothing but fees.
• Depth of US$500,000: estimated slippage on 100,000 USDT is about 200 USDT, twice the 0.1% fee.

So for the same 100,000 USDT purchase: zero fees on a pair with US$500,000 of depth costs roughly 200 USDT, while paying a 0.1% fee on a pair with US$20 million of depth costs about 100 + 5 = 105 USDT. The zero-fee option ends up more expensive. At 10,000 USDT, the zero-fee side costs about 2 USDT and the other side about 10 USDT, so zero fees save money.

To apply this to a real exchange, plug that exchange’s BTC or ETH depth from the depth table above into the formula. For example, if your order is 1% of the depth, estimated slippage is about 0.01%; at 10% of the depth, about 0.1%.

When zero-fee exchanges end up costing more

Here is the method above turned into rules of thumb:

A simple benchmark, taking a 0.1% fee gap as the example: once an order exceeds 10% of the depth, estimated slippage eats up that 0.1% difference.

Transfer costs count too: USDT withdrawal fees vary a lot by network; see How to Choose a USDT Withdrawal Network. Also, fees and depth are only part of choosing an exchange. A zero-fee exchange doesn’t necessarily score well on safety, and for large amounts you should look at proof of reserves, past incidents and licences first; see Choosing a Crypto Exchange by Need.

Four ways to lower your trading costs

1. Use limit orders when you can wait: you set the fill price, there’s no slippage, and you pay the maker rate when it fills. The trade-off is that it may not fill.
2. Split large orders: each batch only eats the first few price levels; wait for the book to refill before placing the next one.
3. Check the best bid, best ask and order book before you trade: the spread and the size of the first few levels matter more than the last traded price on screen.
4. Check the trade details after it fills: at most exchanges, “Orders → Trade history” lists the average fill price and fee for each trade. Compare the average fill price with the mid price when you placed the order to see how much slippage you actually paid.

Invitation codes by exchange

Below are the invitation codes for the international exchanges mentioned in this article. Signing up with an invitation code gets you the official fee discount, at the rate shown in each box. On zero-fee exchanges, the discount only applies to items that carry a fee. I suggest comparing total costs and safety using the method above before deciding whether to sign up.

More exchange guides and comparisons are on the crypto topic page.

FAQ

Are zero-fee exchanges really cheaper?

Not always. Zero fees only save you the trading fee; you still pay the spread and slippage. For small trades on pairs with enough depth, zero fees usually save money. For a large market order on a pair with a thin order book, slippage can exceed the fees you save.

What do trading costs include?

Three main parts: the fee the exchange charges, the spread between the bid and ask prices, and the slippage caused when a large market order eats through several price levels. Withdrawal fees and fiat withdrawal costs for moving money in and out are counted separately.

What is the difference between spread and slippage?

The spread is the gap between the lowest ask and the highest bid in the order book, and even a small market order pays it. Slippage is the gap in your average fill price when an order is too big for the first price level and fills at worse prices further back; the bigger the order and the thinner the book, the larger it gets.

How can I roughly estimate the slippage on a market order?

The simplified method in this article: estimated slippage is roughly the order size divided by the ±2% order book depth, times 1%. For example, if the order is one tenth of the depth, estimated slippage is about 0.1%. This is an estimate that assumes orders are evenly spread, not a quote; your order screen and trade history are what count.

How can I reduce slippage?

Use limit orders so you set the fill price yourself and pay the maker fee when they fill; split large orders into batches; and choose exchanges and pairs with enough order book depth. The trade-off with limit orders is that they may not fill.