Your platform’s day-trade margin will happily wave through a dozen contracts. That number is a trap — it measures what clears, not what your funded account can survive. The size that keeps you in the evaluation is almost always smaller, and it comes from a different rulebook entirely.
Buying power vs the firm’s contract cap
Two separate ceilings decide how many contracts you can hold, and they answer different questions.
- Margin, or buying power, is set by the exchange and your firm’s clearing arrangement — the deposit required to hold one contract. Intraday margins on index futures are a small fraction of the overnight requirement, which is why even a modest account appears to have room for a stack of contracts.
- The contract cap is a hard number the prop firm writes into your account, independent of margin. Your buying power might clear twenty contracts; the firm’s cap may stop you at a handful, and on a well-run firm the platform rejects the order that crosses it.
The error is reading margin as permission. Margin tells you what the exchange will clear. The cap tells you what the firm will tolerate. You always trade to the lower of the two — and it is nearly always the cap. Firms tier these caps by account size and by evaluation stage and revise them often, so read the current rules for your exact plan rather than a number from a forum. Both Apex Trader Funding and Tradeify structure the cap this way; confirm your specific tier before you size a single trade.
Scaling plans that unlock size as you profit
Most futures firms don’t hand over the full contract allowance on day one. They run a scaling plan: your maximum size starts throttled and steps up only as your balance clears defined thresholds above the starting figure.
The reasoning is simple — the firm wants proof you can grow an account with restraint before it lets you swing full size. In practice that means:
- Early in the eval you’re often capped at partial size, sometimes expressed as a percentage of the full contract limit.
- As your balance climbs past each threshold, the ceiling lifts.
- On some plans, dropping back below a threshold lowers the ceiling again.
Scaling plans reward slow compounding and punish the trader who front-loads risk to clear the target in a week. Check whether your plan scales at all — some funded stages drop the scaling once you pass — and confirm the exact thresholds with the firm, because these are among the most frequently rewritten rules.
Why the cap is often lower than the margin allows
The gap is deliberate. The firm is pricing your odds of surviving, not your odds of getting rich fast, and a cap set well under the margin ceiling does three quiet jobs:
- It caps per-trade damage. With a hard contract limit, one bad fill can’t drain a day’s loss buffer in a single tick spike.
- It disables the martingale reflex. Traders who are down tend to add size to “get it back.” A tight cap makes that math impossible before you can talk yourself into it.
- It keeps the daily loss rule enforceable. The cap and the daily loss limit are designed together — the cap ensures no single oversized position can blow the loss limit in one shot.
If you catch yourself resenting the cap, that’s usually the tell that you were about to over-risk. Treat it as a floor of discipline the firm is holding for you.
Micro-contract limits and how they count
Micros let you size in fractions of a full contract, and firms usually express the cap in micro-equivalents. A common convention counts one standard contract as ten micros against your limit, so a cap stated in minis translates to ten times that in micros, and mixing the two draws from the same pool. Conventions differ, though — some firms count each micro as a full unit against the cap — so confirm how yours does the arithmetic.
| If your cap is stated in… | One mini counts as… | Practical read |
|---|---|---|
| Mini contracts | 1 mini | Trade minis directly up to the cap |
| Micro-equivalents | 10 micros | Any mix that sums to the micro ceiling |
Micros are the right tool early in an eval: they let you take a real position, honour the setup, and keep the tick value low enough that a normal losing streak doesn’t threaten the daily limit. Because most sizing tools speak in standard lots, run your intended size through a position size calculator to confirm the per-tick dollar value before you commit — even a few micros on a fast index future move real money per tick.
Sizing to survive, not to max out the cap
The cap is a ceiling, not a target. Sizing to it on every trade is the fastest way to let a routine three-loss cluster tap your daily loss limit.
The durable approach inverts the logic: pick a fixed fraction of your daily loss buffer to risk per trade, convert that into contracts given your stop distance, and let that number decide your size. On most trades you’ll sit well under the cap — which is exactly where a funded account should live.
This is where broker-enforced limits earn their keep. Shibiki pushes your intended per-trade and daily-loss limits down to the broker, so the position that would breach them is rejected before it fills — the cap stops being something you must remember mid-trade and becomes something the account simply won’t let you cross. Paired with auto-journaling and a live edge-health read wrapped in a Wilson confidence interval, you can see whether your real, cap-respecting size is producing genuine positive expectancy or just a comfortable-looking curve. Trade to survive the eval, and the size takes care of itself.
Related: Position size calculator · Apex Trader Funding · Tradeify