Sourced Trader

Coming soon  Browser extension ยท Chrome

Risk Ruler: position-size browser extension

A position-size calculator for your browser's side panel: size from your risk, fees included, reward-to-risk after fees and a liquidation estimate. Never places trades; no data leaves your browser.

Free

Version 1.0.0 is built and tested, but not yet in the Chrome Web Store.

See it in action

The actual extension running in Chrome with example inputs.

30-second silent walkthrough with captions. Example inputs. Locked items in the video are not part of the free extension.
  • Risk Ruler in crypto spot mode: 1% risk on a 10,000 account gives the position size, notional, risk including fees, breakeven and reward to risk after fees.
    Crypto spot. Size from your risk, with fees, breakeven and R:R after fees. Example inputs
  • Risk Ruler in perp mode at 25x leverage, warning that the stop is beyond the estimated liquidation price.
    Perps at 25x. Margin, an estimated liquidation price and a warning when your stop is past it. Example inputs
  • Risk Ruler in stock mode sizing 86 shares from 0.5% risk on a 25,000 account.
    Stocks. Whole-share sizing with fees counted in the risk. Example inputs

Position sizing is simple maths that's easy to get wrong in a hurry, especially with leverage and fees. Risk Ruler sits in your toolbar or Chrome's side panel and does it the same way every time, using the same formulas as the Trading Journal's risk calculator.

What it does

  • Crypto spot, perpetual futures and stock modes, long or short
  • Risk as a percentage of your account or a fixed amount
  • Size rounded down to your exchange's lot step, with contract size and minimum order checks
  • Fees included in your risk, reward-to-risk after fees and breakeven price
  • Perps: notional, margin, margin as a share of your account, an estimated liquidation price and the maximum leverage before your stop is past liquidation
  • Warnings when your stop is beyond the estimated liquidation, fees eat more than 25% of your risk, margin exceeds your account, or you risk more than 5%
  • Copy a one-line trade summary

Private by design

  • Two permissions only: storage (to remember your inputs on this device) and the side panel
  • No access to the pages you visit, no account, no analytics, no ads
  • Makes no network requests at all: your numbers stay in your browser

What it won't do

  • Place, modify or cancel orders. It's a calculator only, not advice
  • Read your exchange account or the pages you browse
  • Guarantee liquidation figures, which are estimates: exchanges use their own margin tiers and mark prices

Tested in headless Chrome against 60 reference cases from the Journal's formulas. Features may change before launch.