What a trade actually costs
The thing almost nobody teaches you — and it decides everything.
Buy something for $100. Sell it for $101.
You made a dollar.
Except you didn't.
You never paid exactly $100, and you never received exactly $101. There were charges you didn't see and prices that weren't quite the ones on your screen. By the time it's finished, your dollar might be sixty cents. It might be nothing at all.
Do that once and it doesn't matter.
Do it four hundred times a year — which is roughly what day trading is — and it decides whether you make money or lose it.
Most trading education skips this. Not out of malice. Costs make every strategy look worse, so there's no comfortable way to raise it while you're teaching one. You get charts, entry points, and where the "smart money" supposedly is. The rest you find out on your own, slowly, with your own money.
I'm starting here instead.
I'm going to teach you this the way I wish it had been taught to me — nothing hidden, nothing hyped, and no pretending I know things I don't. If something isn't settled, I'll tell you it isn't settled. If most people fail at something, I'll say so.
You can decide what to do with that. But you'll decide knowing.
This is free because you should have it before you risk a single dollar.
You don't need to know anything about trading to follow it. If you've never placed a trade in your life, you're in exactly the right place. And it applies to whatever you end up buying and selling — stocks, currencies, crypto. The numbers change. The problem doesn't.
There are always two prices
Open a chart. You see one price. Clean, single number, right there.
Now try to trade it. There are two.
The bid — what someone will pay you if you sell right now.
The ask — what someone will charge you if you buy right now.
The ask is higher. Always. In every market, forever.
That gap is the spread. It's the entry fee, and you pay it twice — once buying, once selling.
One buy plus one sell is a round trip: in and out, the complete cycle. Every cost here is a round-trip cost, because you never just buy — eventually you have to get out too.
Three hands in your pocket
Commissions. What your broker takes. Sometimes zero on stocks. Never zero on everything.
Slippage. The distance between the price you wanted and the price you got. Usually the biggest one, and the one nobody counts.
Market impact. Very large orders push the price away from themselves. This won't affect you for a long time — you're not big enough to move a market. Mentioned so you know it's there later.
Every trade you place begins as a loss.
Not sometimes. Every one.
The instant you're in, you're behind — by the spread plus commission. Before the market has moved a tick. Before you've been right or wrong about anything.
The trade has to come to you by that much just to get you back to zero. Now multiply that by every trade you'll ever take.
What you're actually paying
The spread moves, and it moves against you
It isn't a fixed fee. It widens when the thing you're trading is rarely traded, at the open and the close, and hardest of all when prices are moving fast — which is exactly when the market finally looks worth trading.
The spread that costs you nothing on a dead Tuesday can be several times wider the moment something actually happens. Which is, of course, the moment you want in.
So what's normal? Fair question, and nobody ever answers it.
On something enormous and heavily traded, the spread can be a single cent on a share worth hundreds of dollars — nearly free. On something small and rarely traded, it can be many times wider in percentage terms. Same market, completely different cost.
The point isn't the number. It's that the number is knowable and almost nobody checks it. Yours is on your broker's website right now.
Commission — read the fine print once
Per share, per contract, or per trade? Is there a minimum? Are exchange and regulatory fees separate?
And know this: "commission-free" almost never means free. The cost moved into the spread, where you can't see it and won't think about it. You're still paying. They just stopped telling you.
Slippage — and the thing worth stopping for
Slippage is the distance between the price you wanted and the price you got, because prices move between your click and your fill.
Everyone half-knows that. Here's the part almost nobody does, and if you take one thing from me today, take this.
First, in case you haven't met one: a stop-loss is an instruction you leave with your broker saying "if this goes against me and reaches this price, get me out." It's the safety net — how you decide in advance the most you're willing to lose. Almost every trader uses one. Almost every course tells you to.
And a stop-loss is not a price. It's a trigger.
"The stop price is not the guaranteed execution price for a stop order. The stop price is a trigger that causes the stop order to become a market order. The execution price an investor receives for this market order can deviate significantly from the stop price in a fast-moving market."
U.S. Securities and Exchange Commission
Read it again slowly. The second your stop triggers, it stops being a stop. It becomes an order to sell at whatever price exists right then.
Picture it
You buy at 105. You're willing to lose five dollars, so you set your stop-loss at 100. You've done everything right. You know exactly what this trade can cost you. You've made peace with it.
Then news hits. Everyone tries to sell at once. There is nobody left willing to buy at 100, or 99, or 97.
Your order goes out looking for a buyer and finds one at 94.
You didn't lose five dollars. You lost eleven. And you found out at the same moment everyone else did.
Your stop worked perfectly. It did exactly what a stop does.
It just wasn't what you thought you'd bought.
So when you tell yourself "I'm only risking 1% here" — hear what you're actually saying. That's an expectation, not a contract. And it's least reliable in exactly the conditions where you're relying on it most.
Orders that never fill
Sometimes your order doesn't fill at all, or only part of it does. It happens because the price moved past where you were willing to trade before your order arrived, or nobody wanted the amount you asked for.
95–99% filling is normal. Consistently below 90% in calm conditions is worth a question to your broker.
You pay per trade, not per year
Someone who buys a stock and holds it two years pays the spread twice. Twice, in two years.
You pay it on every round trip. Ten trades a day is roughly 2,500 round trips a year.
The same cost that's a rounding error to an investor becomes the largest single force acting on your account. Larger than your strategy. Larger than your discipline.
And we know this, because someone counted
There's a study that examined every trade on an entire stock exchange for fifteen years. Not a survey, not a sample.
Here's what the average day trader earned per day, as a share of the money they had at risk:
| Before costs | −0.07% |
| After costs | −0.24% |
Small numbers. Let's make them real.
On a $10,000 account that's about $24 a day. There are roughly 250 trading days in a year. Do that multiplication yourself.
And look at the two lines together. Before costs, the average day trader was mildly bad at this — recoverable, a skill problem. After costs, they were finished.
Roughly 70% of the damage was costs.
Not bad entries. Not poor timing. Not weak psychology. Not any of the things every course on earth is selling you a fix for.
And it's worse if you trade the way you're being taught
Costs don't fall evenly. Some strategies chase a move that's already underway — you see something rising fast, you jump on. Those bleed far more than strategies that wait for price to come back to them.
Think about why. If you're buying something already shooting up, you're buying from someone who can see exactly how badly you want in. They price accordingly.
And chasing the move is what nearly every popular day trading strategy does.
Trading more often does not give you more chances to win. It gives you more chances to pay.
If your edge per trade is smaller than your cost per trade, every extra trade makes you poorer, faster. It doesn't matter how beautiful the setup was. It doesn't matter that you were right.
Costs have a schedule
You probably assume costs are a flat tax. A toll you pay at the door and forget.
They don't work like that. Spreads are widest at the close.
Now think about how much advice sounds like this:
Advice you've heard
"Close everything by 3:45."
"Never hold overnight."
Sensible rules. Genuinely good risk management. And if you follow them, you're exiting in the most expensive window of the day. Every day. For as long as you trade.
You could be paying a premium on a habit you've never once questioned.
So: notice when you actually enter and exit. If it's always the same time, ask honestly whether that's a decision or something you copied. And if your method demands a close at the bell, keep it — but price it. Don't pretend it's free.
A real strategy, taken apart
Everything above is abstract until you watch it happen to a strategy that actually worked.
So watch.
A trader has a genuine edge. Not imagined — tested, measured, real. On average it makes 1.4 units of profit per trade. (In currency trading these units are called pips. The name doesn't matter. The arithmetic does.)
That's a real strategy. Most people never get one.
Now take it out of the spreadsheet and put it in a live account.
| The edge | +1.4 |
| Spread | −0.8 |
| Slippage | −0.3 |
| Still standing | +0.3 |
Nearly 80% of it, gone. And we're not finished.
Now add a 12% rejection rate — roughly one order in eight never fills. And here's the cruelty: the ones that don't fill aren't random. They're disproportionately the good ones, because the good ones are the fast ones, and fast is hardest to catch.
The edge is gone.
Nothing was wrong with the strategy. The chart reading was correct. The logic was sound. The trader did everything right. It just wasn't big enough to survive contact with a real market.
The same story, with real money on the table
An automated currency strategy went live in March 2020. The world came apart. Spreads went from 0.6 to 5.
Same code. Same rules. Same logic, running exactly as designed. Only the cost of trading changed — and that alone turned +340% into −60%.
And when it goes wrong, it goes wrong to real people
October 2016. A flash crash in the British pound. A trader had a stop-loss sitting exactly where it should be. They lost 11,000 dollars instead of the 3,000 they'd planned for and accepted.
The stop worked. It triggered exactly when it was supposed to.
The fill didn't.
So why would anyone do this?
Fair question. I've just spent two thousand words explaining why the odds are against you.
Here's my honest answer.
A small number of people do make it work. Not by finding a magic setup — I've never seen one and I'd be lying if I told you I had. They make it work by understanding exactly what they're up against and building around it. They know their costs to the cent. They trade less than they want to. They're ruthless about only taking trades actually worth the friction.
That's the whole game. It isn't a hidden indicator or a secret session time.
It's arithmetic, done properly, by someone who bothered.
Almost nobody bothers. That's the entire opportunity, and it's also exactly why most people lose.
I'd rather you know that now than find out in eighteen months.
What you now know that most traders never will
- Every trade starts as a loss. Before anything happens.
- Your stop-loss is a trigger, not a price. It fills wherever the market happens to be.
- Costs scale with frequency — irrelevant to an investor, decisive for you.
- In the largest study ever done, costs caused around 70% of day traders' losses.
- A strategy can look profitable on a chart and lose money in reality — with nothing wrong with your analysis.
Do this before you trade anything
You can't work out your cost per trade yet, because you haven't got a strategy. That comes later.
Here's what you can do today. It takes four minutes.
Open your broker's fee page. If you haven't got a broker yet, pick any one and go find theirs. Three things:
- What do they charge per trade?
- What's the spread on something you're curious about?
- Is there anything else — inactivity fees, data fees, withdrawal fees?
Write the numbers down somewhere you'll see them again.
I'm asking because most people trading right now have never once looked. They'll spend years blaming their entries, their timing, their mindset — cycling through course after course hunting for the missing piece. And the whole time, the money was leaving through a door they never thought to check.
You just checked. That already puts you ahead of most of them.
Where I'm taking you next
That was one problem. There are others nobody's told you about either, and I'd rather be the one to do it.
How much money you actually need to start — and what your account will and won't let you do below certain amounts. What your stop-loss really protects you from, and what it doesn't. How a strategy can win 75% of the time and still lose you money. What happens at tax time, which nobody mentions until it's too late to plan for.
The full beginner course is all of it, in order, from zero. No assumed knowledge.
Same deal as this lesson. Nothing hyped, nothing left out because it's awkward, and I'll tell you when something isn't settled instead of pretending it is.
If that's how you want to learn this, I'll see you at the start of the course.