Tools · run them on the spot
Three quick risk calculators
They don't predict prices and they won't tell you what to buy. They only nail down the three numbers most worth getting clear on: how far a loss has to climb back to break even, how much you can actually buy on this trade, and whether the risk and reward are worth it.
All three of these run in your own browser. The amounts, accounts and prices you type in never get sent to any server — refresh the page and they're gone. They also won't tell you whether to "buy now" or "sell now" — that kind of thing doesn't exist. They just do arithmetic somewhere between primary-school and middle-school level, turning the fuzzy feeling in your head into one concrete, slightly painful number.
The place beginners trip up most isn't reading the direction wrong — it's losing their feel for the numbers. You tell yourself "down 50%, a 50% bounce gets it back," that "ten grand all in isn't really that much," that "if this bet's right I double, if it's wrong I lose a bit." Every one of those three sentences is wrong, and wrong in an expensive way. The three tools below exist to break those three illusions.
I'd play with them in order: first use the recovery calculator to feel the weight of "can't afford to lose," then the position calculator to work out how much to buy, and finally the risk-reward tool to see whether a trade is worth taking. The longer reads that go with them are in how much to put in first and position sizing.
1. Recovery calculator
Recovery calculator
How far has your stake dropped? See how much it has to climb back to break even.
Pure math, no network, no price predictions. Formula: gain needed = drop ÷ (100 − drop). The deeper the loss, the harder it is to recover — which is exactly why job one is not losing too much.
How to use it: enter your starting amount, then the percentage you're already down. It shows how much is left in the account and — this is the number that matters — how far it has to climb from here for you to break even. Drag the drop from 10 to 50 to 80 and watch the "gain to break even" figure jump higher and higher.
The formula: gain needed = drop ÷ (100 − drop). Sounds abstract, but an example makes it click. Down 10%, you need about 11% to recover — roughly symmetric, no big deal. Down 50%, you're left with half and need 100% to get back — the stake has to double. Down 80%, you've got a fifth left and need 400% to break even, that is, a five-bagger off the bottom.
Why this matters: because losses and gains aren't symmetric. Your head quietly assumes they are, so without noticing you start tolerating big drops, averaging down, white-knuckling. But the math has no mercy: the more you lose, the more absurd the bounce you need, and absurd bounces mostly never arrive. Once that sinks in, your attitude toward stops changes completely. Cutting at −15% versus holding to −60% is a difference of more than ten times in how hard it is to recover.
This is also why the first lesson on this site isn't how to pick coins, but the constant nagging to "not lose too much." Once you're deeply underwater, even brilliant moves rarely save you; the cheapest fix is always to never let the hole get big in the first place. For the full version that breaks out how much a 30% / 50% / 80% loss needs to climb, read the math of losses and recovery.
2. Position calculator
Position calculator
Decide the most you're willing to lose on this trade first, then work back to how much to buy.
Pure math, no network, no price predictions. The logic: set "the most I'll lose on this trade as a percent of the account" first, then use the gap between entry and stop to work back to how much you can buy. The stop has to differ from the entry, or there's nothing to compute. This isn't a suggestion to buy — it just gets your numbers straight.
How to use it: four numbers. Account total is all the money you plan to put toward crypto (not your net worth — the part you can commit to this market). Risk per trade is the most you're willing to lose, as a percent of the account, on this one trade; for beginners I'd start at 1%. Entry is the price you plan to buy at, stop is the price where you say "if it drops here, I admit I'm wrong and leave." Fill those in and the four figures below pop out on their own.
Which number to watch: "units you can buy" and "position size" are the answers the tool works out — that's the most you can buy so that, if this trade hits its stop, you lose only the amount you set. "Max loss on this trade" is the loss you've agreed to accept on paper, and "share of account" tells you how big a slice this position actually puts to work. If that share is alarmingly large, it's usually because your stop sits too close to your entry.
The logic behind it: there's a plain practice in professional trading called fixed risk per trade, often shorthanded as the "1% rule" — every trade, no matter how convinced you are, loses only a fixed small slice of the account (say 1%). Units = the amount you can lose on this trade ÷ (entry − stop). In other words, what decides how much you buy isn't how confident you are — it's how far your stop sits from your entry and how much you've agreed to risk. Flip the order completely: set the loss first, then the position.
Why size it this way: because people pile in heaviest exactly when they "feel sure," and that's exactly the most dangerous moment. Handing position size to a fixed rule pushes emotion out of the order. Even if you're wrong five times in a row at 1% each, the account survives and you've still got plenty of chances; but bet the farm on a feeling and one wrong call can end the game. The full walkthrough is in position sizing: let a single trade lose at most 1% of your account.
Heads up
This tool computes "the most you can buy under your rules," not "buy this much." Whether to buy, what to buy, at what price — that's all your call and your responsibility. It also leaves out trading fees, slippage and gaps, so a real fill may lose a bit more than the number shown.
3. Risk-reward tool
Risk-reward tool
On this trade, is the room to gain worth the room to lose? And what win rate do you need just to break even?
Pure math, no network, no price predictions. Risk-reward = distance from target to entry ÷ distance from stop to entry. The "win rate to break even" is the minimum win rate this ratio needs to avoid losing over the long run — not a promise you'll actually hit it.
How to use it: three prices. Entry, stop, and target (the level where you'd take profit). Fill them in: on the left is this trade's risk-reward, and on the right is an often-ignored number — at this ratio, what fraction of trades you'd have to win over the long run just to break even.
How risk-reward is figured: risk-reward = room to gain ÷ room to lose = (target − entry) ÷ (entry − stop). Say you enter at 300, stop at 270 (risking 30), target at 390 (aiming for 90) — that's a ratio of 1:3, one win covers three losses. Anything below about 1:1.5 is usually a poor deal, because you'd have to be right almost every time to avoid losing, and nobody is right every time.
That win-rate number is the key: break-even win rate = 1 ÷ (1 + risk-reward). At 1:1 you have to win more than half to avoid losing; at 1:3, winning just over a quarter keeps you even. Once that lands, you'll re-read an old line: let your winners run, cut your losers short. When the ratio is high enough, you can be wrong often and still come out flat or ahead — provided you actually walk at the stop every single time you're wrong.
Why it matters: beginners fixate on win rate, thinking "eight out of ten" is what makes you good. But someone who's right only 30% of the time at 1:3 still makes money long term; someone right 70% of the time who keeps taking tiny gains and white-knuckling big losses watches their account shrink. Looking at risk-reward and stops together beats agonizing over "will it go up this time." Of course, this is only the mathematical break-even line — it doesn't guarantee you'll steadily hit that win rate. There are no guarantees in this market.
How to use all three together
They're really one assembly line. Start with something you want to buy and a price, use the risk-reward tool to see whether the trade's risk and reward stack up — if they don't, walk away, no need to buy at all. If they do, use the position calculator to work out how much to buy at "at most 1% of the account on this trade." And if you do buy and end up deep underwater, use the recovery calculator to remind yourself how hard breaking even is, and why you have to admit you're wrong at the stop. String the three numbers together and you've got a dumb, reliable method built on discipline, not prediction.
A note
These three tools only do math. They're not investment advice and they don't predict any coin's moves. Crypto is extremely volatile and your whole stake can go to zero. Use only spare money, decide for yourself, take responsibility yourself. To start building your own risk habits from scratch, read how much to put in first, then why beginners should stay away from futures and leverage.