SIZING¶

Every way to specify the size of a BUY or SELL order. Sizing is the single mandatory field on entry actions (unless DEFAULTS.sizing is set).

The forms available today¶

Form	Meaning
`SIZING <expression>`	Computed lots / units
`SIZING <expression> PCT OF EQUITY`	Percentage of total equity (cash + open P&L)
`SIZING <expression> PCT OF BALANCE`	Percentage of cash balance only
`SIZING <expression> USD`	Computed USD notional value
`SIZING <N> PCT RISK`	Sized so a stop-out loses N% of equity (sugar over `SIZING RISK N/100`)
`SIZING <N> PCT RISK OF BOOK`	Sized so a stop-out loses N% of the portfolio book balance
`SIZING RISK $ <expression>`	Computed account-currency risk with bracket stop geometry
`SIZING POSITION.<stream>`	The full current position quantity (for closes/scaling)

Fixed quantity¶

BUY btc SIZING 0.1

Buys 0.1 of whatever the venue's unit is. For Bybit spot BTC, that's 0.1 BTC. For MT5 EURUSD, that's 0.1 lots = 10,000 units of base currency.

When to use: prototyping, simple strategies, when the venue's lot size aligns with your risk budget at known prices.

Gotcha: doesn't scale with account size. A 0.1 lots size on a $1,000 account is risky; on $100,000 it's tiny. Use percent-based sizing for portable strategies.

Percent of equity¶

BUY btc SIZING 5.0 PCT OF EQUITY

Sizes the position at 5% of ACCOUNT.equity. If equity is $10,000, the order is sized to represent $500 of position value (at current price).

Variants:

SIZING 5.0 PCT OF EQUITY    -- 5% of equity (includes open P&L)
SIZING 10 PCT OF BALANCE    -- 10% of cash balance only (ignores open P&L)

The difference matters when you have unrealized P&L: EQUITY includes it (the size scales with open profit/loss), BALANCE doesn't.

Convention: the number before %/PCT is always a percentage, in every sizing form. SIZING 5.0 PCT OF EQUITY and SIZING 5.0 % OF EQUITY both mean 5% (fraction 0.05), the same way SIZING 0.5 PCT RISK means 0.5% (fraction 0.005).

When to use: position sizing that scales with account performance. Good for compounding strategies.

Fixed USD notional¶

BUY btc SIZING 1000 USD

Sizes the position to represent exactly $1000 of notional value (at current price). For BTC at $50k, that's 0.02 BTC. For BTC at $60k, that's 0.01666… BTC.

When to use: consistent dollar exposure across symbols of different price levels. "I want $1000 of BTC and $1000 of EUR regardless of how each is priced."

Position-based (for partial closes)¶

SELL btc SIZING POSITION.btc

Sells exactly the current position size — equivalent to CLOSE btc. Mostly used in scale-out logic:

SELL btc SIZING 0.5 * POSITION.btc     -- partial close: 50% of position

You can multiply, divide, or do any arithmetic on POSITION.<stream>.

Risk-percent sizing¶

BUY btc SIZING 0.5 PCT RISK
    BRACKET { STOP LOSS AT btc.close - atr(btc, 14) * 2, TAKE PROFIT RR 3 }

Sizes the position so that, if the stop hits, the loss is exactly N% of equity. SIZING 0.5 PCT RISK is sugar for SIZING RISK 0.005 — both compile to the same engine path. Use the PCT form to avoid decimal-shift bugs when expressing small risk fractions: 0.5 PCT RISK is unambiguous; RISK 0.005 invites typos. The engine resolves AT, expression-based BY, and PCT stop prices with the current entry geometry before it computes the order quantity.

Requires a BRACKET with a STOP_LOSS — without one the compiler rejects the strategy because no stop distance can be established safely. N must be a numeric literal: the percent is converted to a fraction while the file is parsed, so a PARAM, LET or arithmetic expression in that position is rejected (SIZING N PCT RISK requires a numeric literal for N). To compute the risk budget, use SIZING RISK <fraction-expr> or SIZING RISK $ <expr> instead.

STRATEGY risk_no_stop VERSION 1
SYMBOLS
    btc = BACKTEST:BTCUSDT EVERY 1m
RULES
    WHEN btc.close > btc.open THEN BUY btc SIZING 0.5 PCT RISK
-- compile error: SIZING RISK <fraction> requires a resolvable stop distance via BRACKET STOP LOSS

PARAM riskPct = 0.5
RULES
    WHEN btc.close > btc.open
    THEN BUY btc SIZING riskPct PCT RISK BRACKET { STOP LOSS BY 100, TAKE PROFIT BY 200 }

PARAM riskFrac = 0.005
RULES
    WHEN btc.close > btc.open
    THEN BUY btc SIZING RISK riskFrac BRACKET { STOP LOSS BY 100, TAKE PROFIT BY 200 }

When to use: the default for portable strategies. Risk-percent sizing scales correctly with account size, stop distance, and instrument volatility.

Portfolio book risk¶

BUY btc SIZING 0.5 PCT RISK OF BOOK
    BRACKET { STOP LOSS BY 500, TAKE PROFIT BY 1000 }

OF BOOK is available to portfolio children and uses CAPITAL + realized PnL across all children. It deliberately excludes unrealized PnL, so an open-book drawdown does not reduce subsequent sizes. Treat that balance-style basis as a leverage risk; use book exposure and drawdown limits to cap new exposure. A standalone strategy, or a portfolio child without a bound book balance, fails closed instead of falling back to strategy equity.

Computing risk-based size manually¶

The same effect is also achievable with USD sizing and a LET expression — useful when you want the size to factor in something PCT RISK doesn't model (e.g. correlation across positions):

LET stopDist = atr(btc, 14) * 2
LET riskUsd  = ACCOUNT.equity * 0.01           # 1% of equity at risk
LET riskQty  = riskUsd / stopDist              # size that loses riskUsd if stop hits

RULES
    WHEN ema(btc.close, 9) CROSSES ABOVE ema(btc.close, 21)
    THEN BUY btc SIZING riskQty
         BRACKET { STOP LOSS AT btc.close - stopDist, TAKE PROFIT AT btc.close + stopDist * 3 }

This is equivalent to SIZING 1.0 PCT RISK with the same bracket — you compute the size from equity_at_risk / stop_distance yourself. Reach for the manual form only when you need a sizing expression PCT RISK doesn't express.

Streak-Adjusted Risk¶

Risk sizing accepts any numeric expression, including the trade-streak ledger:

RULES
    WHEN ema(btc.close, 9) CROSSES ABOVE ema(btc.close, 21)
     AND STREAK.losses < 2
    THEN BUY btc SIZING RISK $ (100 + 0.30 * STREAK.banked)
         BRACKET { STOP LOSS BY 40, TAKE PROFIT BY 90 }

This is anti-martingale sizing: base risk remains $100, and only current win-streak profit is pressed. STREAK.banked resets to 0 after a losing close.

Computed set-once sizing¶

Every numeric sizing form above carries an expression, not just a numeric literal. That means inverse-volatility and discrete conviction tiers can be composed directly with a structural bracket. Risk sizing converts the computed account-currency budget through the resolved stop distance, contract size, and quote-to-account rate at the normal sizing boundary:

LET conviction = CASE
  WHEN sweepConfirm AND vrConfirm AND silverConfirm THEN 2
  WHEN sweepConfirm AND vrConfirm THEN 1.5
  ELSE 1
END
LET riskBudget = 100 * conviction

RULES
  WHEN shock AND POSITION.gold = 0
  THEN SELL gold SIZING RISK $ riskBudget BRACKET {
    STOP LOSS AT gold.high + 1.2 * atr(gold.candle, 14),
    TAKE PROFIT AT sma(gold.close, 20)
  }

The sizing expression is evaluated once when the action constructs the order request. The resulting request carries a fixed quantity through submission and fill; it is not reevaluated on later bars. Use RESIZE only when continuous target rebalancing is intentional.

Quantity cannot be selected after the order's own fill because the venue requires quantity at submission. "Set once at entry" therefore means evaluation from the latest deterministic strategy state when QKT creates the entry order. Bracket stop geometry is available to PCT RISK, SIZING RISK <fraction>, and SIZING RISK $ <expression> during that evaluation.

Defaults via DEFAULTS¶

If most of your strategies use the same sizing, hoist it:

DEFAULTS {
  SIZING = 0.1
}

RULES
    WHEN ema(btc.close, 9) CROSSES ABOVE ema(btc.close, 21)
    THEN BUY btc     -- inherits SIZING = 0.1

Multiple sizings per stack¶

A STACK (pyramid) carries one SIZING for the seed layer, but you can override per layer in the layer-list form:

BUY btc STACK [
  0.05,                       -- seed: 0.05 lots
  0.10 AT entry + 200,        -- layer 2: 0.10 lots at +200
  0.15 AT entry + 400         -- layer 3: 0.15 lots at +400
]
BRACKET { STOP LOSS BY 300, TAKE PROFIT BY 1000 }

See STACK.

Common gotchas¶

Sizing is required. Either on the action or via DEFAULTS { SIZING = ... }. Both missing = compile error (BUY/SELL requires SIZING).
Percent-of-equity ignores stop distance. A 5% position with a tight stop loses very little; with a wide stop loses a lot. Use the manual workaround above to factor in the stop.
Broker volume bounds. MT5 brokers enforce minimum/maximum lots (volumeMin, volumeMax) and a step (volumeStep). A computed size outside the bounds rejects after downward step quantization.
Whole-number lots on some venues. Futures often require integer contracts. A computed size of 0.327 will round (typically down) or reject. Check your venue's specs.
Sizing units are venue-side. A "size of 0.1" means 0.1 of the venue's unit (lots, contracts, base currency) — not 0.1 USD or 0.1% of anything.
Computed entry sizing is set once. It does not track the expression after QKT emits the order. Use RESIZE for deliberate per-bar rebalancing.

What this composes with¶

Actions — SIZING is a modifier on BUY / SELL
BRACKET — pair sizing with STOP_LOSS/TAKE_PROFIT
LET — name a sizing computation for reuse
DEFAULTS — set a default sizing for the whole strategy
Planned features — PCT RISK and what's coming