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School of Trading (education only)

Trading Costs: spreads, commissions, swaps, rebates and cashback (education only)

What you'll be able to do
  • Measure the bid/ask spread in money and in percent, for a share and for a currency pair.
  • Work out commissions charged per trade, per share, per lot and per round turn.
  • Explain overnight financing (swap or rollover) and estimate it with a simple formula.
  • List the "other" costs: currency conversion, deposit and withdrawal fees, inactivity fees, data fees and slippage.
  • Explain payment for order flow and how a "commission-free" broker still earns money.
  • Explain how rebates, cashback and introducing-broker (referral) programs work: who pays whom, why a rebate only lowers cost and is never profit, and how it can push people to trade too much.
  • Add up the total yearly cost of a trading plan on a simple worksheet.

This course is education only. It does not recommend, rank or name any broker, rebate service or introducing broker, and it contains no referral or affiliate links. All firms in examples ("Broker A", "Broker B", "Referrer C") and all prices are made up, round numbers chosen to make the math easy. It gives no buy or sell signals, no predictions and no promises of income. Real fees differ by firm, product and country: always read the firm's own fee schedule and your regulator's guidance, and consult a licensed professional before making decisions with real money.

Before this course: Brokers Explained (course 5.19) shows what brokers do and how they are paid. Forex and Gold Basics (course 5.6) introduces spreads and overnight financing, and Types of Trading (course 5.11, Lesson 6) gives a first list of trading costs. This course turns those costs into numbers you can calculate. Next: Orders, Lots and Margin (course 5.21) and Trading Essentials (course 5.22).

Words in this course 50Open the Vocabulary Hall
01

The bid/ask spread and how to measure it

In simple words

At a money exchange booth at the airport, the booth buys your dollars for one price and sells dollars for a higher price. The gap between those two prices is how the booth gets paid. In trading, that gap is called the spread, and you pay it every time you buy and then sell.

Key facts
  • Bid = the highest price a buyer will pay right now (the price you can sell at). Ask (or offer) = the lowest price a seller will accept (the price you can buy at). Spread = ask - bid.
  • FINRA explains that bid-ask spreads represent the difference between the highest price a buyer will pay and the lowest price a seller will accept, and that for exchange-traded products the spread "might be almost zero for some ETPs but much wider for other products".
  • The spread is a cost even when no commission is charged. The OSC (GetSmarterAboutMoney) notes it can be "a more significant cost if you trade frequently".
  • Spreads can widen around big news (course 5.6, Lesson 5).
  • Formula. Spread cost of a round trip (buy, then sell at the same quoted prices) = spread x quantity. Spread in percent = spread / mid price x 100, where mid price = (bid + ask) / 2.
Example (made-up numbers)
Share exampleCurrency pair example
Bid$20.001.1000
Ask$20.051.1002
Spread$0.05 per share0.0002 (2 pips)
Quantity100 shares100,000 units of the base currency
Spread cost of one round trip100 x $0.05 = $5.00100,000 x 0.0002 = 20.00 in the quote currency (USD here)
Spread in percent of mid price0.05 / 20.025 x 100 = about 0.25%

What this means: if you bought at the ask and sold a moment later at the bid, with the prices unchanged, you would be down $5.00 on the share trade. The price must move by at least the spread just for you to break even before any other costs.

Step by step
  1. Open a practice platform or the Academy's Chart Lab and pick one market (names of panels can differ by platform).
  2. Find the two prices shown for it: bid (sell) and ask (buy). Write both down.
  3. Subtract: ask - bid = spread.
  4. Multiply the spread by the quantity you would trade, to get the spread cost in money.
  5. Work out the mid price and the spread in percent.
  6. Repeat at a different time of day (or around a scheduled news release in practice mode) and compare.
  7. Check: for bid $20.00 and ask $20.05 on 100 shares, you should get $5.00 and about 0.25%.
Watch on YouTube
What is the bid-ask spread?Ryan O'Connell, CFA, FRM · YouTube · youtube.com

Videos by other creators on YouTube, for reference. They are not made by or affiliated with The Future Market.

LESSON 01The bid/ask spread and how to measure it
LESSON 01 / ANIMATED LESSON00:00 / 01:05
Read the video script
[Host] "Every trade has a toll booth built in. It is called the spread."
[Screen: a quote box showing bid 20.00 and ask 20.05] "You buy at the ask, twenty dollars and five cents. You sell at the bid, twenty dollars even."
[Text on screen: spread = ask - bid = $0.05] "That five-cent gap is the spread. On a hundred shares, that is five dollars."
[Text on screen: 0.05 / 20.025 = about 0.25%] "In percent, about a quarter of one percent, paid on every round trip."
[Screen: the same quote box with the spread widening during news] "Around big news, the gap can get wider."
[Host] "So before you ask 'how much can I make?', ask 'how far must the price move just to pay the toll?'"
Try it now

Using made-up quotes, fill a three-row table: bid, ask, spread, quantity, spread cost and spread percent. Use (1) bid $50.00 / ask $50.10 for 20 shares, (2) bid $5.00 / ask $5.02 for 500 shares, (3) your own example from a practice screen. (Answers for 1 and 2: $2.00 and $10.00.)

ClaudeStuck? Copy a ready-made prompt for Claude

Copy this, open Claude, paste it, and Claude will walk you through the lesson step by step.

For a grown-up: Claude is for adults (18+). Copy this, paste it into Claude, and use the answer to explain the lesson to your child.

I'm learning "Trading Costs: spreads, commissions, swaps, rebates and cashback (education only)" on The Future Market. Lesson 1: "The bid/ask spread and how to measure it".

What the lesson teaches:
- Bid = the highest price a buyer will pay right now (the price you can sell at). Ask (or offer) = the lowest price a seller will accept (the price you can buy at). Spread = ask - bid.
- FINRA explains that bid-ask spreads represent the difference between the highest price a buyer will pay and the lowest price a seller will accept, and that for exchange-traded products the spread "might be almost zero for some ETPs but much wider for other products".
- The spread is a cost even when no commission is charged. The OSC (GetSmarterAboutMoney) notes it can be "a more significant cost if you trade frequently".
- Spreads can widen around big news (course 5.6, Lesson 5).
- Formula. Spread cost of a round trip (buy, then sell at the same quoted prices) = spread x quantity. Spread in percent = spread / mid price x 100, where mid price = (bid + ask) / 2.

The exercise I'm working on:
Using made-up quotes, fill a three-row table: bid, ask, spread, quantity, spread cost and spread percent. Use (1) bid $50.00 / ask $50.10 for 20 shares, (2) bid $5.00 / ask $5.02 for 500 shares, (3) your own example from a practice screen. (Answers for 1 and 2: $2.00 and $10.00.)

I'm stuck. Please:
1. Explain the main idea in plain, simple words with one everyday example.
2. Walk me through the exercise one small step at a time. Ask me what I've done so far before giving the next step.
3. Don't just give me the final answer. Help me do it myself, and check my work when I share it.
4. This is for learning only. Remind me to check with a licensed professional before I make a real decision about my own money, health or legal situation.
I'm a parent helping my child (about 8 years old) with a lesson called "The bid/ask spread and how to measure it" from the course "Trading Costs: spreads, commissions, swaps, rebates and cashback (education only)".

Here's what the lesson says:
At a money exchange booth at the airport, the booth buys your dollars for one price and sells dollars for a higher price. The gap between those two prices is how the booth gets paid. In trading, that gap is called the spread, and you pay it every time you buy and then sell.

The activity:
Using made-up quotes, fill a three-row table: bid, ask, spread, quantity, spread cost and spread percent. Use (1) bid $50.00 / ask $50.10 for 20 shares, (2) bid $5.00 / ask $5.02 for 500 shares, (3) your own example from a practice screen. (Answers for 1 and 2: $2.00 and $10.00.)

Please explain this so an 8-year-old understands: short sentences, a fun everyday example, and no hard words.
Then give me 3 simple questions I can ask my child to check they understood, and a way to do the activity together, one tiny step at a time.
Keep it general and educational. This is not advice for a real situation.
Open Claude
Sources
My notes
02

Commissions: per trade, per share, per lot and round turn

This lesson is part of full access: every course and every level for one payment.

03

Overnight financing, swap and rollover

This lesson is part of full access: every course and every level for one payment.

04

The other costs: currency conversion, deposits and withdrawals, inactivity, data and slippage

This lesson is part of full access: every course and every level for one payment.

05

Payment for order flow and "commission-free" trading

This lesson is part of full access: every course and every level for one payment.

06

Rebates, cashback and introducing-broker (referral) programs

This lesson is part of full access: every course and every level for one payment.

07

Comparing the total cost of a plan: a worksheet

This lesson is part of full access: every course and every level for one payment.

++

Final project

This lesson is part of full access: every course and every level for one payment.

??

Quiz

  1. What is the spread?

  2. Bid $20.00, ask $20.05, 100 shares: what is the spread cost of one round trip?

  3. What does "round turn" mean?

  4. Why do flat commissions hurt small trades most?

  5. What is the simple formula for overnight financing?

  6. Name three "other" costs besides spread and commission.

  7. What is payment for order flow?

  8. Is payment for order flow allowed in Canada?

  9. Can a "commission-free" broker cost more than one that charges commission?

  10. Who ultimately pays for a trading rebate?

  11. Does a rebate make a trade more likely to win?

  12. Why is trading more to earn more rebates a bad idea?

EX

Final exam

This lesson is part of full access: every course and every level for one payment.

CE

Certificate

This lesson is part of full access: every course and every level for one payment.