Position Size Calculator Pro

The one-paragraph version, for the top of a sales page.

A pre-trade position sizing tool for Sierra Chart, drawn directly on the chart and modelled on TradingView's long/short position tool. You place an entry, a stop and up to four targets; it tells you how many contracts to trade, exactly what the trade risks in money, what each target pays, and the resulting reward-to-risk ratio — all of it net of commission.

Two things separate it from a calculator in a side panel. It is anchored to a candle, so it stays where you put it as new bars print, which makes it a record of a trade you took as much as a plan for one you are considering. And it is driven from the chart — grab a handle, press a button on the box itself — rather than from a settings dialog.

The box

The setup is drawn as stacked filled bands: a risk band from the entry down to the stop, and a reward band from the entry out to each target. The bands meet exactly at the entry and at every target, so the edges where they meet are the levels — there are no separate level lines to style or to misalign.

The box begins one bar to the right of the anchor candle and extends as far right as you drag it. With Box: Width at 0 it sizes itself to the widest label with a little air either side, and it will never be narrower than its own text.

The handles

Four triangular markers sit just left of the box, one per draggable thing, each in the colour of the label it belongs to:

Nothing can be dragged across the entry — a stop cannot become a target by accident. Direction changes only through the flip button.

Which of risk, size and stop distance is the input, and which are solved for.

The active mode is written into the entry label, so a locked stop never looks like a frozen study. The + and − buttons change position size in Variable and Fixed Risk; in Auto Size, where size is an output, they step the risk amount instead.

Everything on the labels comes from these. Commission is round-turn, per contract.

StopTicks     = |Entry − Stop| / TickSize
TargetTicks   = |Target − Entry| / TickSize

Risk          = Quantity × (StopTicks × TickValue + Commission)
Reward[t]     = TargetQty[t] × (TargetTicks[t] × TickValue − Commission)

R:R           = Σ Reward[t] / Risk          // net of commission on both sides

The ratio is taken from the net money figures rather than from the raw tick counts. With commission at zero the two are identical, which is why a gross ratio looked correct for a long time; set commission to $4 and a gross ratio contradicts the two currency amounts printed beside it.

Fixed Risk, solving for the stop

RiskPerContract = RiskAmount / Quantity − Commission
StopTicks       = max(1, floor(RiskPerContract / TickValue))
Target[t]       = Entry ± StopDistance × R[t]

Auto Size, solving for the quantity

CostPerContract = StopTicks × TickValue + Commission
Quantity        = floor(RiskAmount / CostPerContract)
                  clamped to Sizing: Maximum Position Size

When that lands below one contract, the stop costs more than the entire risk budget. Rather than quietly drawing a plausible 1, the label says so: Stop too wide for $250. Tighten the stop or raise the risk amount.

Fixed Risk has the mirror of that fault and now the mirror of the warning. Commission is charged per contract whatever the stop does, so a large enough size consumes the whole budget before the stop is given any room — 50 contracts against $250 of risk at $4 commission leaves $1 per contract to cover $4 of cost. The stop used to pin silently to one tick; the label now reads Size too large for $250.

Up to four targets, each with an R multiple (where it sits, as a multiple of the stop distance) and a share of the position.

Shares are weights, not percentages. They need not add up to anything in particular: 50 / 30 / 20 and 5 / 3 / 2 produce exactly the same split. The resulting contract count appears in brackets on each target's label.

Stepping a target's share down to nothing removes that target — its band, label and handle all go with it. That is the intended way to drop a target, and it is why there is no separate remove button.

Exact formats, so a manual can reproduce them and support can recognise them.

All labels are padded to a common character count so they share one width and sit centred in the box. That only produces equal pixel widths in a monospaced face, which is why the default is Consolas and why the input is named to hint at it.

Bottom-left of the box. Two rows, plus one per target, and a clean view behind H.

Row one — the position

Row two — how the size is decided

One row per target

Only once there are two or more targets to divide the position between. Each row is a chip naming the target and a pair of steppers for its share.

Every glyph is an input, so a customer whose font lacks one of the symbols can type any character they like into it. The default face is Segoe UI Symbol, which carries all four of the mode and flip glyphs; Consolas does not.

Everything except X, H, the flip arrow and the target chips shares one colour — by default a lighter shade of the entry label's grey-blue, so the cluster reads as part of the box without competing with the numbers on it.

Three ways to place it

• Drag the entry handle. The whole setup travels, box width included, and re-anchors to the candle you drop it on. This is the everyday gesture.
• Right-click the chart and choose Position Size Calculator Pro. It lands at the exact point you clicked — that candle, that price — carrying your stop and target distances with it. It also brings the tool back if you have hidden it.
• Drag it past the last candle. The empty space to the right is fair game, for a level you are waiting on. The width handle keeps working out there.

Hiding preserves everything

The red X takes the tool off the chart and keeps the mode, contract count, target count and shares, stop and target distances, direction and box width. Right-click to bring it back exactly as you left it. The grey H is a lighter version of the same idea: it hides only the handles, for a clean look while you read the chart.

The study reads Tick Size and Currency Value Per Tick from the chart it sits on, so it works on any instrument the platform can chart without configuration.

That makes one chart setting load-bearing for every figure the tool reports. If Currency Value Per Tick is wrong, nothing errors — every number simply scales by the same factor, and the results still look plausible. The classic case is trading micros on a chart configured for the full-size contract: ES is 12.50, MES is 1.25, so risk is reported ten times too large.

Where a chart's values cannot be corrected, Symbol: Tick Size Override and Symbol: Currency Value Per Tick Override take precedence; both are 0 = use the chart setting. If the chart reports a zero or nonsensical tick value, the study writes a warning to the Message Log naming the symbol and the bad values rather than silently drawing nothing.

What was verified, and how

On 3 September 2026 both editions were audited line by line for anything that assumes a particular instrument. The findings and their fixes:

All 55 inputs, in the order they appear in the study's settings window. Each carries a description shown in the platform when you select it.

Symptom first, because that is what a customer arrives with.

A buyer who reads these first sees honesty; a buyer who discovers them first sees a bug.