Position sizing: cap each trade at 1% of your account

I know two people who entered the same asset at the same time. The market came down and the asset dropped 20%. One shrugged it off — "no big deal, lost a few hundred, stopped out." The other went pale, because he'd gone heavy with most of his net worth, and that 20% cost him tens of thousands, which he was still refusing to admit. Same read, same asset, same drop, wildly different endings. The difference wasn't whose judgment was sharper — it was entirely position size. This piece is about the thing that decides whether you "lose a few hundred" or "lose tens of thousands": how to set your position.

Here's the core method up front: fixed per-trade risk, commonly called the "1% rule." In one line — on any single trade, even if you're completely wrong and get stopped out, the loss is only 1% of the account (or whatever small ratio you set). I didn't invent this; it's a practice professional traders have used for years, all over public trading education. I'm just translating it into a method an ordinary person can pick up, with a calculator to do the math for you.

Same rule as always, ugly truth first: crypto swings violently and you can lose all your principal. This article covers risk-control method only — no calls, no return promises, and it is not investment advice. Position sizing helps you lose less and last longer, but it can't guarantee you a profit. Every amount below is a "say you have this much" example, there to plug into the formula.

Why size matters more than "what to buy"

Beginners spend nine-tenths of their energy on "what to buy" — which coin is going up, which hot name to chase, which rumor to believe. But what decides whether you survive long-term in this market is usually not "what to buy," it's "how much to buy." What you buy decides how well you play this one hand; how much you buy decides how many hands you can afford to lose and whether you stay at the table at all. Someone with average coin picks but a restrained position will usually pull through; someone with a sharp eye who goes all in every time will sooner or later be wiped out by one or two surprises.

Term Position: the amount you've actually put into an asset, or the quantity you hold. Position sizing is the whole set of methods for systematically deciding how much to put into each trade and keeping risk within what you can bear — the heart of money management.

Behind this stands the previous piece, the math of recovery: because loss and recovery are asymmetric, one heavy trade that blows up and drops you deep underwater means the gain you need to recover gets absurdly steep. Someone with a light position takes the same blow-up as a one- or two-percent account drop, and trades the next one as normal. The entire point of position sizing is to pin the cost of every "wrong" trade firmly in shallow water, never letting any single trade cripple you.

Fixed per-trade risk: decide your max loss first

This method starts with a counterintuitive move: before you place an order, decide "the most I'm willing to lose on this trade," and fix that number as a small percentage of the account. The most common in professional trading is 1%, meaning — even if this trade is all wrong and the stop is hit, I only lose one percent of the account.

Term The 1% rule: fixing each trade's maximum loss at 1% of the account total (some use 0.5% to 2%). It's a widely used money-management rule in trading; its aim isn't to raise your win rate but to make the account fall slowly enough during a losing streak that you always stay in the game.

One percent sounds stingy and unexciting — a hundred-thousand account, and a trade can only lose a thousand, so you can't make much either. But its real power is on defense: be wrong ten times in a row and the account only drops about a tenth, still firmly seated; dare to risk 10% per trade and ten losses in a row leaves you with just over a third, basically a slow path out. What this rule protects isn't any one trade, it's your right to "still get another go." A beginner who sets this between 0.5% and 1% is already more sensible than most.

Keep two numbers apart: one is "how much money goes into this trade" (the position size), the other is "how much I'm prepared to lose on this trade" (the per-trade risk). They are not the same thing at all. You buy in with $10,000 but put the stop at -15%; then the risk you're actually exposed to is just $1,500, not $10,000. Pulling those two numbers apart is the first step from gambler thinking toward risk-control thinking — what you manage is never "how much to invest," it's "how much to lose."

Work back from the stop to how much to buy

With "the most this trade can lose" set, the next step is to calculate the position. The whole method needs only three inputs: the money you're willing to lose on this trade, your entry price, and your stop price. The core formula is one line:

quantity you can buy = the money you're willing to lose ÷ (entry price − stop price)

That denominator, "entry price − stop price," is what you'd lose per unit held if the stop is hit. Divide the total you can lose by the per-unit loss and you naturally get "the most units you can buy." Here's a clearly labelled example, the same set of numbers as the home page and the cover: say you have $50,000 and set per-trade risk at 1%, so this trade can lose at most $50,000 × 1% = $500. You like an asset and plan to enter at $300, having decided that if it falls to $270 (that's -10%) you'll admit you're wrong and get out. Then each unit loses at most $300 − $270 = $30, so $500 ÷ $30 ≈ 16.6 units, and multiplying back by entry, 16.6 × $300 ≈ $5,000 — that's the position you should build.

Careful This step assumes you'll actually exit at the stop price. If it falls to $270 and you go soft and hold on, the whole calculation is void and the per-trade risk is no longer $500. However elegant the math, if you don't execute the stop, position sizing is just a worthless piece of paper.

Note the formula uses the absolute difference between entry and stop — whether you're long with a stop below or short with a stop above, you take the distance between the two prices. The calculator already takes the absolute value for you; you just enter the prices correctly.

Run it through the position calculator

You don't have to do this by hand. The position calculator below is the same one on the home page and the tools page. Plug in the account total, the percent you'll risk per trade, the entry price, and the stop price, and it spits out the most this trade can lose, the quantity you can buy, the position size, and the share of the account this trade takes. I'd suggest trying it once with your own real account numbers — that's far more useful than reading the example.

Try it After you plug the numbers in, watch the "share of account" figure. If it jumps to something high (say above 60%), it usually means your stop is set too close, or your risk ratio is too large, and the position isn't actually comfortable. All three tools are on the Tools page.

Your max loss at different risk ratios

How to choose the per-trade risk ratio — the table below gives you a visual reference. For the same account, moving the ratio from 0.5% to 5% changes both the most you can lose per trade and what's left after ten losses in a row by orders of magnitude. These are illustrative levels, not numbers you must copy, and certainly not hints about returns. Beginners should try to stay in the first two rows.

The "left after 10 losses in a row" column is an approximation from compounding, not a scare — it's there to show the real consequence of per-trade risk size. At 1% you're still at about 90% after ten losses; at 5% you're left with about 60% — and 60% means you need a 67% gain to recover, right back to the wall in the recovery math. Every notch you push the ratio up, the deeper the hole you dig for yourself.

A counterintuitive detail: a wider stop means you buy less

Once you've used this formula a while, you'll notice a detail that feels awkward at first and great once it clicks: the closer the stop is to entry, the more you can buy; the farther the stop, the less you can buy. This is the opposite of many people's instinct — the instinct says "I like it, I'm confident, so I should buy more," but the formula tells you how much you can buy has nothing to do with confidence, only with stop distance and per-trade risk.

The reasoning is straightforward: a wider stop means each unit loses more if the stop is hit, so to pin the total loss firmly under $500, you naturally have to buy fewer units. Conversely, a near stop means a small per-unit loss, so the same $500 budget buys more units. So position size isn't decided by "how confident I am," it's calculated from two objective numbers — where my stop goes, and how much I'm prepared to lose.

This trait also cures an old bad habit: a lot of people "buy heavier the more they like something," and one misread costs them dearly. With this method your position is pinned by the stop and the risk ratio, so no matter how much you like it you can't blow it up without limit — it's a physical brake on impulse.

A few traps that break this method

The method itself is reliable, but a few moves can break it completely, and they're all common beginner mistakes. I'll name them so you can steer around.

Not executing the stop. As said, the foundation of the whole calculation is "you'll actually exit at the stop price." Go soft and hold past the stop and the per-trade risk goes from $500 to a bottomless pit. However precise the math, if your hand doesn't move it's all for nothing. The stop is the lifeline of this method.

Setting the stop absurdly close. Some people, to buy more, set the stop right against the entry, and then normal noise sweeps them out, getting cut by the stop over and over. The stop should sit where "if it's really hit, it shows my read was wrong this time," not crammed in close just to inflate the position.

Careful This method manages "your risk exposure when you're right on direction"; it assumes you can fill at the price and stop out normally. The moment you take high leverage, liquidation and price wicks can blow through you before you can even stop out — which is exactly why beginners shouldn't touch leverage, all detailed in why beginners should leave contracts and leverage alone. Position sizing is a skill you master in spot; don't borrow it to give leverage false courage.

Opening a pile of correlated positions at once. You honestly risk only 1% per trade, but if you open five highly correlated assets at the same time, you've effectively bet 5% in one direction at once. One market move turns all five red together, and the per-trade protection is bypassed. When you tally the total, treat correlated positions as a single trade.

In the end, position sizing is one line: decide how much to lose first, then calculate how much to buy, then obediently execute the stop. Make this a fixed pre-order routine and you'll find you couldn't go heavy even if you wanted to, because every trade is blocked by two calm questions first. That's not a restriction, it's the seatbelt that keeps you in the game. As a next step, read risk-reward ratio and win rate — position size decides how much one trade can afford to lose, while the risk-reward ratio decides whether the trade is even worth doing, and you need both together. Then use those small tools to run your own numbers by hand. Take it slow, and learn not to lose first.