Try the Margin Calculator Widget
Free for any site, including commercial ones. Keep the small credit line at the bottom of the widget so readers can find the full version. Nothing is stored about the people who use it. See the disclaimer.
How to add it to your site
- Copy the code above Use the copy button so nothing is lost to line wrapping. It is a single iframe tag and it does not need anything else.
- Open the page you want it on In WordPress add a Custom HTML block, in Wix use the Embed HTML element, in Squarespace use a Code block, and on a hand-built site paste it straight into your HTML.
- Paste and publish The widget appears immediately. If you see an empty space instead, your editor has stripped the iframe tag, which the HTML embed guide explains how to work around.
- Adjust the look if you want to Add the parameters in the table below to the iframe URL to change the theme, the accent colour or the height. Nothing needs to be configured on our side.
Customisation options
| Parameter | Values | What it does |
|---|---|---|
theme | auto, light, dark | Default follows the reader's own system setting, so the widget looks right on a dark site and a light one without you choosing. |
accent | Six hex digits, e.g. accent=1A56DB | Recolours the header bar and the primary button to match your brand. |
header | 1 or 0 | Set to 0 to hide the title bar when your page already has a heading above the widget. |
breakdown | 1 or 0 | Set to 0 to hide the calculation breakdown for a more compact block. |
corners | 1 or 0 | Set to 0 for square corners if your design has no rounding anywhere else. |
width | full | Removes the 520px maximum so the widget stretches to its container. |
Parameters are added to the iframe URL as a normal query string, for example
/embed/position-size-calculator.html?theme=dark&accent=1A56DB&header=0. The
widget builder lets you set all of them visually and hands you the finished code.
What the widget calculates
The widget calculates required margin as notional position value divided by the leverage ratio, then shows both figures together with the free margin left over from a given account balance. Changing the leverage while watching the margin figure move is usually the moment the concept lands for a reader.
The breakdown makes each step explicit, so a reader can see that leverage does not reduce their exposure, only the deposit needed to take it on, which is the distinction that most beginners get backwards.
Who this widget suits
Broker education pages
Regulators increasingly expect leverage risk to be demonstrated rather than disclosed in small print.
CFD and forex blogs
Pairs with any article about leverage limits, margin calls or account sizing.
Course modules on account management
Readers can run their own numbers instead of following someone else's example.
Related widgets
- Leverage Calculator WidgetLeverage Calculator
- Position Size Calculator WidgetPosition Size Calculator
- Lot Size Calculator WidgetLot Size Calculator
- Forex Calculator WidgetForex Calculator Set
The full library of free trading widgets has more than eighty tools, and the widget builder lets you preview and configure any of them before you copy the code.
Frequently asked questions
What leverage ratios does the margin calculator widget support?
Anything a reader enters, from 1:1 through to the high ratios offered by offshore brokers. The FSCA does not impose a single retail leverage cap the way some regulators do, so South African traders encounter a wide range and the calculator does not restrict it artificially.
Does it handle instruments priced in dollars with a rand account?
Yes, and that conversion is shown in the breakdown rather than applied silently. It is the step most often missed, and getting it wrong understates the margin a rand account actually needs.
Is margin the same as the cost of the trade?
No, and the widget is designed to make that clear. Margin is collateral that is set aside and returned when the position closes. The costs are the spread, any commission and overnight financing, which the trading cost calculator handles separately.
Can I embed this next to the position size widget?
Yes, and the two work well together, since position size answers how large a trade should be and margin answers whether the account can carry it. Each iframe is independent. Give them separate headings so readers know which is which.
Does the widget know my broker's margin requirements?
No. It applies the leverage ratio the reader enters. Individual brokers set their own margin requirements per instrument and can raise them around major events, so readers should confirm the figure in their platform before relying on it.