How do I use Position Sizer on Zeplik?

Sign in to Zeplik and ask in plain language, or type /position-sizer in any chat to invoke it directly. The skill applies its method and returns a result you can refine in the same conversation.

Which AI model does the Position Sizer skill use?

Any model you choose. Zeplik works across every model in one chat, so the Position Sizer skill runs on your preferred model for the task.

Where does the Position Sizer skill come from?

The Position Sizer skill is adapted from the open-source tradermonty/claude-trading-skills project (MIT) and tuned to run natively on Zeplik. The original source is linked on this page.

How much does the Position Sizer skill cost?

Using the skill is free to start. You only spend Zeplik credits when the assistant runs, and new accounts begin with free credits.

Position Sizer

Investing skill, available on Zeplik

Position Sizer is a ready-to-run investing skill on Zeplik. Calculate a risk-based position size -- share count from account size, entry, and stop, with the risk math shown. Ask in plain language and Zeplik applies the skill's method for you inside the conversation, on whichever AI model you prefer.

The Position Sizer skill loads automatically when your request matches it, or you can invoke it directly by typing /position-sizer in any chat. It works with attachments, connectors, and any model that supports the task, so you get the same expert method every time without setting anything up.

What the Position Sizer skill can do

Apply the Position Sizer method to your investing task
Calculate a risk-based position size -- share count from account size, entry, and stop, with the risk math shown
Handle related work: position sizing, shares to buy, risk per trade, stop-loss distance
Get a clear, structured answer you can act on right away

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Pick a prompt to open it in the Zeplik app. If you are not signed in yet, your prompt is waiting for you the moment you do.

How the Position Sizer skill works

Position Sizer

Framing: Position sizing is arithmetic on the user's own risk budget, not a call on the trade. Gather the inputs, show every step, and let the user change any of them. This is a risk-management worksheet, not investment advice.

Quick start

Ask which method fits, then collect only the inputs it needs. Never invent an account size, entry, stop, or win rate -- ask, or state a clearly labeled assumption the user can override.

Fixed fractional -- risk a fixed percent of equity per trade (default 1%). Needs account size, entry, stop, risk %.
ATR-based -- set the stop distance from volatility. Needs account size, entry, ATR, ATR multiplier (default 2.0x), risk %.
Kelly criterion -- size from a measured edge. Needs win rate, average win, average loss; optionally entry and stop to convert to shares.

Path 1: Fixed fractional

Dollar risk budget = account_size x risk_pct.
Risk per share = entry - stop (long) or stop - entry (short). Must be positive.
Shares = floor(dollar_risk / risk_per_share) -- whole shares unless the user confirms their broker supports fractional shares for this order.
Position value = shares x entry; report it as a percent of the account.

Path 2: ATR-based

Same as Path 1, but derive the stop first: stop = entry - (ATR x multiplier) for a long. Then size on that stop distance. State the ATR value and multiplier used.

Path 3: Kelly criterion

W = win rate (0-1), R = average win / average loss.
Kelly fraction f* = W - (1 - W) / R. If f* is zero or negative, the edge does not support a position -- say so.
Recommend fractional Kelly (typically one-quarter to one-half of f*) because full Kelly is highly volatile and assumes the win/loss stats are stable.
Convert the chosen fraction to a dollar risk budget, then to shares as in Path 1.

Concentration checks

After sizing, flag if the position value exceeds a sensible single-position cap (default 10% of equity) or if it would push a sector above the user's stated limit. These are guardrails to surface, not automatic reductions.

Guardrails

Risk budget is the user's. Never assume an account size or risk tolerance silently.
Positive risk per share. If entry and stop imply zero or negative risk, stop and ask.
Whole shares by default. Only size fractional shares when the user confirms broker support.
Not advice. A size under stated assumptions, not a recommendation to take the trade.

How to use the Position Sizer skill

Sign in to Zeplik
Create a free Zeplik account or sign in. New accounts start with free credits, so you can try the Position Sizer skill right away.
Describe your investing task
Ask in plain language, or type /position-sizer to invoke the skill directly. Zeplik recognizes the Position Sizer skill and applies its method.
Review and refine the result
Zeplik returns a clear, structured answer. Ask follow-ups in the same chat to refine it or take the next step.

Source and credit

Author: TraderMonty
License: MIT

Adapted from the open-source tradermonty/claude-trading-skills project and tuned to run natively on Zeplik. View source on GitHub.

Frequently asked questions

What is the Position Sizer skill?: Position Sizer is a ready-to-run investing skill on Zeplik. Calculate a risk-based position size -- share count from account size, entry, and stop, with the risk math shown. Ask in plain language and Zeplik applies the skill's method for you inside the conversation, on whichever AI model you prefer.
How do I use Position Sizer on Zeplik?: Sign in to Zeplik and ask in plain language, or type /position-sizer in any chat to invoke it directly. The skill applies its method and returns a result you can refine in the same conversation.
Which AI model does the Position Sizer skill use?: Any model you choose. Zeplik works across every model in one chat, so the Position Sizer skill runs on your preferred model for the task.
Where does the Position Sizer skill come from?: The Position Sizer skill is adapted from the open-source tradermonty/claude-trading-skills project (MIT) and tuned to run natively on Zeplik. The original source is linked on this page.
How much does the Position Sizer skill cost?: Using the skill is free to start. You only spend Zeplik credits when the assistant runs, and new accounts begin with free credits.

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