26 calculators
Plan a trade before you place it.
Every tool states the formula it uses and the assumptions behind it, so the number can be checked rather than trusted. Size the position first, then work outwards to cost, reward and long-run performance.
A free account saves your trade plans, your instrument defaults and your performance statistics, and opens the quant curriculum.
A calculator answers one question and immediately raises the next. Taken in order they describe a single trade end to end, and most of the mistakes people make with them come from taking one out of that order.
| Stage | What it decides |
|---|---|
| Account → risk | How much one loss costs, in dollars, before you look at a chart |
| Risk → position size | The size that makes the stop cost exactly that. Size is an output, never an input |
| Position size → margin and leverage | What the broker holds, and what your actual exposure is |
| Trade → costs | Spread, commission and swap, all paid whichever way the trade goes |
| Results → expectancy | Whether the strategy earns anything, once win rate and payoff are combined |
| Expectancy → drawdown and ruin | What a bad run does, and whether the account survives it |
Each calculator states the equation it uses, works an example through it with the page’s own default inputs, and lists what it assumes. That is there so the result can be checked by hand — a number you cannot reproduce is a number you are trusting rather than using.
Where this goes wrong
Margin is not risk. A position can sit comfortably inside your margin and far outside your risk budget, and confusing the two is the most common way an account becomes over-leveraged without anyone noticing.
Four mistakes account for most of the wrong answers these calculators produce, and none of them is a fault in the arithmetic.
The categories describe stages of one decision rather than separate topics.
| If the question is | Start at |
|---|---|
| How large should this position be | [Position size](/position-size-calculator), then [stop loss](/tools/stop-loss-calculator) if the size is fixed |
| What will this trade cost me | [Spread](/tools/spread-calculator), [commission](/tools/commission-calculator) and [swap](/tools/swap-calculator) if held overnight |
| Is this strategy actually profitable | [Expectancy](/tools/expectancy-calculator), then [break-even](/tools/break-even-calculator) to see what the payoff demands |
| Can my account survive this | [Drawdown](/tools/drawdown-calculator), [risk of ruin](/tools/risk-of-ruin-calculator) and [Kelly](/tools/kelly-criterion-calculator) |
| How volatile is this instrument | [ATR](/tools/atr-calculator), [ADR](/tools/adr-calculator) and [volatility](/tools/volatility-calculator) |
Every one of them shows the equation it evaluates and a worked example using its own defaults, so a result can be checked by hand before it is trusted.