Enter your grid’s spacing, lot size at level 1, lot multiplier, and position cap, then a currency pair, account equity, and a one-directional adverse move to stress-test. The simulator computes each level’s floating loss and shows where a fixed-lot grid and your entered multiplier start to diverge.
Grid blow-up simulator
Enter spacing, lot size, cap, pair, equity, and an adverse move above to run the simulation.
Educational tool, not investment advice. Margin, swap, and spread are not modelled — only the pip-distance floating loss per level. A real account can be stopped out by margin before this simulation's cumulative loss is reached. Verify against your own broker's contract specification and margin requirements.
Quick Answer
This simulator applies loss_i = lot_i × pip value × (move − i × spacing) to each filled level, where lot_i = lot × multiplier^(i-1), and sums the result. Levels filled is min(floor(move / spacing), cap) — the cap models a hard, software-enforced position limit, not a margin call. It also compares the cumulative loss at a multiplier of 1.0 (the rule-based grid blueprint’s own fixed-lot rule) against whatever multiplier you enter, so a lot-multiplier or grid-martingale setup can be checked against a straight grid on the same hypothetical move. Margin, swap, and spread are not modelled — only the pip-distance floating loss.
How the Simulator Works
A grid ladder places orders at fixed intervals and, in a one-sided move, fills one side level by level without closing. Why grid EAs blow up walks through why that happens and names the failure patterns; this tool lets you put your own spacing, lot size, and cap into that mechanic and see the dollar figures instead of a schematic example.
Four things happen when you fill in the fields:
- Levels filled is computed from your adverse move divided by spacing, capped at your entered position limit — a level beyond the cap never opens, because the cap is enforced regardless of how far price has moved.
- Each filled level’s lot size scales by your multiplier raised to the level’s position in the ladder, starting at 1.0 for level 1. A multiplier of exactly 1.0 means every level is the same size — the rule-based grid blueprint’s own rule.
- Each filled level’s floating loss is that level’s lot size times the pip value times how far the move has carried past that level’s own entry point.
- The running total and its percentage of the equity you entered, plus — if you entered an acceptable drawdown percentage — the first level at which that budget is exceeded.
The Formula, and Where It Comes From
levels filled (k) = min(floor(move / spacing), cap)
lot at level i = lot_1 x multiplier^(i - 1)
loss at level i = lot_i x pip_value x (move - i x spacing) for i = 1..k
This is the general form of the rule-based grid blueprint’s own worst-case formula, MaxFloat = lot x pip_value x spacing x L x (L + 1) / 2 — that formula is the special case of the sum above at multiplier 1.0 and a move that lands exactly one spacing past the last filled level (the point the blueprint’s hard cap is designed to stop). This simulator generalizes it to any move and any multiplier so the lot-multiplier failure pattern in why grid EAs blow up, pattern 2 can be checked against pattern 1’s exposure mechanic with real numbers instead of a single worked example.
How to Read the Result
The headline line gives the total floating loss and its share of the equity you entered. Below it, one line tells you the first level at which your own acceptable-drawdown figure would be crossed — if you left that field blank, the tool says so instead of assuming a number for you. A third line compares the cumulative loss at your entered multiplier against what the identical move would cost at a fixed lot size (multiplier 1.0): the gap between those two numbers is the cost the lot multiplier alone adds, holding spacing, lot size, cap, and the move constant. The per-level table underneath breaks out every filled level individually — lot size, that level’s own loss, the running cumulative loss, and cumulative loss as a percentage of equity — so you can see exactly which level pushes the total past any threshold that matters to you.
None of these numbers are a forecast of what your pair will actually do. They are the arithmetic consequence of the move, spacing, lot size, multiplier, and cap you chose to test — margin requirements, spread cost on each fill, and swap are not modelled, and a real account can be stopped out by a margin call before the simulator’s own cumulative-loss figure is reached.
Related Reading
- Why Grid EAs Blow Up: 7 Failure Patterns — the failure mechanics this simulator lets you test with your own numbers
- Grid Trading vs Martingale — the lot-multiplier risk curve in full, including a parameter-sheet test for spotting escalation in a published EA
- Grid Trading Strategy: How It Works + Free EA — the rule-based blueprint this simulator’s formula generalizes
- Grid Spacing Calculator — derive a spacing figure from an ATR reading before running it through this simulator
Educational tool, not investment advice. Trading foreign exchange carries a high level of risk. Past performance is not indicative of future results. Always test on a demo account before trading live.