Lot size decides everything: risk per trade, pip value, how fast an account dies. Most beginners eyeball it. The math is simple — risk amount ÷ (stop-loss in pips × pip value) — but it changes per pair, per account currency, per contract size. So I built PipAtlas: free, no-signup calculators for BTCUSD, NAS100, XAUUSD and majors, plus a pip calculator and a glossary. No ads, no email wall. Feedback welcome — what would you add?
Try them: https://pipatlas.com
Top comments (4)
I would add the broker volume step and minimum lot to the result. Round the calculated size down to the allowed step; if that falls below the minimum, show that the trade cannot fit the chosen risk. Rounding up to the minimum silently breaks the risk budget. A symbol-specific contract-size override would also help with NAS100 and XAUUSD.
Arnold — you were right on all three, and the first one is the dangerous one: rounding up to a minimum silently breaks the risk budget, which is the exact opposite of what a sizing tool is for.
Shipped today on the calculator:
• Volume step is now an input (0.01 / 0.001 / 0.1 — broker-specific). The result rounds DOWN to it, never up, and shows the ideal unrounded size alongside.
• Below the minimum lot, it now refuses: "this trade cannot fit your chosen risk" — with the honest outs (wider stop, cent account, skip) instead of a silently inflated position.
• Units-per-lot override so XAUUSD (100 oz) and index CFDs show real unit counts instead of fake forex units.
The per-pair preset pages get the same treatment in the next update. This is exactly the kind of review that makes the tool better — if you spot anything else, the forum's open.
One correction to the suggested outs: a wider stop makes the minimum-lot problem worse. With a $10 risk budget and $0.10 per pip at 0.01 lot, a 150-pip stop risks $15. Widening to 200 pips risks $20. The valid choices are a smaller stop only if the strategy permits it, a smaller contract or cent account, or skipping the trade. I would remove "wider stop".
Correction accepted — and it's a sharp one. At the minimum lot the risk is stop × pip-value, so widening the stop moves the budget the wrong way: your $10 → $15 → $20 example is exactly right. "Wider stop" is gone from the live page — the warning now offers a smaller stop (only if the strategy permits, and noting why wider is worse), a cent account or smaller contract, or skipping the trade. It also turned out the same bad advice was sitting in two FAQ entries (one since the original launch), so you just fixed three spots in one comment. Two reviews, two real fixes — the per-pair presets get both updates in the next pass. If you ever want to tear into the risk-reward or margin calculators, they're open season.