On a Doubling Grid, the Next Order Is Bigger Than Everything Before It
On a grid that doubles its lot each step, every new order carries more lots than all earlier same-direction orders put together. Lot growth alone does not decide maximum loss: step spacing and the market path still matter.
The idea: exposure depends on both the starting lot and how many steps are allowed (plus spacing and path). Sizing only from the first order misses most of the same-direction basket.
Step 1. The arithmetic. With base lot b, step n opens b × 2^(n−1). Prior same-direction lots sum to b × (2^(n−1) − 1). So each order equals the existing same-direction position plus one base lot.
Step 2. Same-direction totals (illustrative: base 0.01, EURUSD ≈ $10/pip per lot on a USD account; no spread or swap):
| Step | Order lots | Same-dir total | Basket $/pip |
|---|---|---|---|
| 1 | 0.01 | 0.01 | $0.10 |
| 2 | 0.02 | 0.03 | $0.30 |
| 3 | 0.04 | 0.07 | $0.70 |
| 4 | 0.08 | 0.15 | $1.50 |
| 5 | 0.16 | 0.31 | $3.10 |
| 6 | 0.32 | 0.63 | $6.30 |
By step 6 the basket moves 63× faster per pip than step 1 alone. An illustrative additional 50-pip adverse move after all six legs are already open costs about $315 on that basket (0.63 × $10 × 50), excluding spread and swap — not a cumulative loss as the legs filled. The same 50-pip move with only the first leg open would be about $5.
Step 3. Cap by steps. Cap = b × (2^k − 1) allows exactly k same-direction steps. With base 0.01: 0.15 → 4 steps, 0.31 → 5, 0.63 → 6. Each extra step doubles the terminal order; aggregate exposure grows by slightly more than 2× (0.31 → 0.63 ≈ 2.03×), because the new order equals the prior total plus one base lot.
The reframing: ask both base lot and max steps, then separate last-order $/pip from whole-basket $/pip (step 6: 0.32 → about $3.20/pip vs 0.63 → about $6.30/pip).
For grids that place their next step as a pending order, VRD Guardian lets you set a lot cap per EA: it warns at 80% of the cap and deletes that EA's pending orders at 100%. It works per EA and has no account-wide equity stop or daily loss limit.
What to do today: for each grid or martingale EA, write base, max steps, and cap = base × (2^steps − 1). On your symbol, note last-order $/pip and whole-basket $/pip separately.
Try it: Try the free demo of VRD Guardian in the Strategy Tester: its sample panel opens a 7-leg grid so you can watch the lot-usage bar and the bands on labelled sample data (alerts are off in the Tester). $79 to buy, or rent for $30 for 1 month.
https://www.mql5.com/en/market/product/204797
Virtual Risk Desk
Figures are illustrative. Pip values vary by symbol and account currency. A lot cap limits further pending exposure; it does not prevent losses on open positions. Educational content, not trading advice.
