Free · Embeddable · No sign-up

Margin & Break-even Calculator

Trace one order dollar from the price on the page to the money you keep, then see the most you can pay to acquire a customer.

The interactive companion to the playbook The Money You Actually Keep.

Physical products, shipping, returns.

The order
Cost of goods (per unit)
Selling costs
Refunds

You keep · per order – – of revenue
Break-even CPA – max to acquire one order
Required ROAS – to break even (ex-tax revenue)

CPA vs break-even
Cost to acquire (CPA)
–
Max bid per click
–
New orders / mo
–
Contribution / mo
–
Profit after ad spend / mo
–
What most calculators get wrong
  • Refunds taken off revenue, not margin. A refund doesn’t just hand back the sale price; it removes the contribution you would have kept, and you usually eat the selling costs anyway. Applying the refund rate to revenue understates the real damage.
  • Returned goods treated as fully recoverable. A returned unit is rarely 100% resellable. Counting full recovery quietly flatters cost of goods on every refunded order.
  • Stopping at gross margin. Gross margin ignores percentage and fixed selling fees and the refund leak. The number that decides what you can spend to acquire a customer is the contribution you actually keep.

This one is cash-flow-correct instead. Cash-flow-correct margin: a refund loses the sale and the selling costs, and returns goods only to the resellable extent. The Universal Margin (research), Christopher White

Put this calculator on your own site, free

Two lines of code. It stays in sync, costs nothing, asks nothing.

If your audience would find this useful, host it. Paste the snippet below where you want it to appear. The tool runs from this site, so it updates itself; it adapts to your visitor's business model, solves backwards from a target, and gives them a "Copy for LLM" and "Copy my numbers" button so they can carry the work into their own AI, briefing it on the margin model and on your business too. It even co-brands itself: a small badge pairs your site's icon with mine, so it reads as a collaboration. No sign-up, no script bloat, no tracking of your visitors.

Paste the URL of the page you'll embed the tool on. We'll read its colours and fonts and show you what the calculator would look like in your brand.

Reading your site…

Extracted colours

Click an area below, then tap colours above to paint it. The area stays selected, so try a few quickly. The green (money kept) and red (leaks) are generated automatically so the chart always reads right.

Background
Text
Accent
Border
Fine-tune surfaces (cards, fields, buttons, active tab)
Cards
Fields
Buttons & tabs
Active tab

Pick a colour from the strip above

How the collaboration badge will appear:

Christopher White × A tool from Christopher White Consulting, provided by Your website. The full playbook, The Money You Actually Keep, explains every stage. 
<div data-cwc-tool="margin-calculator" data-cwc-title="Margin & Break-even Calculator by Christopher White Consulting" data-cwc-reserve-narrow="2200" data-cwc-reserve-wide="1320" style="min-height:1320px"></div>
<script src="https://christopherwhite.com.au/embed/loader.js" data-cwc-tool="margin-calculator" async></script>
  1. Paste the two lines where you want the calculator to appear.
  2. Use a real HTML / "embed code" block, not a rich-text field, so the <script> survives.
  3. Publish. It loads instantly and auto-sizes its height; nothing to set, nothing to maintain.
Platform notes: WordPress, Webflow, Shopify, Squarespace, Wix…
  • WordPress: a Custom HTML block (Classic editor: the Text tab).
  • Webflow: an Embed element, then publish.
  • Shopify: a Custom Liquid / Custom HTML section in the theme.
  • Squarespace: a Code block (Business plan or higher).
  • Wix: Embed Code → Embed HTML / Custom Code.
  • Framer, Ghost, Carrd, Notion sites: the platform's "embed HTML" / "custom code" block.

Stuck? Paste the install guide into ChatGPT, Claude or Gemini and it'll walk you through your exact platform, or just point your AI at christopherwhite.com.au/embed/install.md.