Free Wire Size Calculator Widget
The embedded Wire Size Calculator converts a load current, one-way run distance and source voltage into a recommended AWG wire size — checking both NEC ampacity and a voltage drop target, and recommending whichever calls for the larger conductor. It fits electrician and contractor sites, wire/cable suppliers, and solar, battery and 12V/24V system builders.
It's a single iframe — free, responsive, no registration, and it adds no link, ad or tracking script to your page.
Live preview
The embed adds no link, no ads and no tracking to your page. Prefer a guided version with a preview? Use the embed builder.
One small ask
Nothing links back to us from the widget itself. If your readers find it useful, please add a credit link to the Wire Size Calculator somewhere on your page — that's what keeps it free to maintain and helps others discover it.
Where the Wire Size Calculator widget fits
- An electrician or electrical supply company's sizing-help page
- A "what wire size do I need" or solar/battery wiring guide
- A cable or wire manufacturer's product selection page
How to add it to your site
- Plain HTML: drop the snippet in wherever the calculator should sit.
- WordPress: use a “Custom HTML” block for the snippet — the “Paragraph” block will strip the iframe out.
- Squarespace / Wix / Webflow: use their “Embed” / “Custom Code” / “HTML” element and drop the snippet in.
- The second line (
embed.js) is optional and just keeps the frame height fitted to the content — one copy per page covers every calculator on it.
Sizing & responsiveness
Use 100% width to fill whatever column it's in, or a fixed pixel value for a sidebar. Height takes care of itself with embed.js — the frame tracks the calculator's actual content, results included. Without that script the frame holds at 950px and still functions, just with a scrollbar on smaller screens.
Questions from site owners
Is there a cost or a catch?
No — it stays free with no account, no API key and no usage cap, and nothing is added to your page in exchange: no injected link, no ads, no tracking. If a tool ends up useful to your readers, a plain credit link somewhere on the page is appreciated, not required.
Does embedding it hurt page speed or collect visitor data?
It shouldn't — the calculator sits in an iframe, so it can't block your page from rendering, and it loads no third-party ad or analytics scripts and sets no cookies on your visitors. The optional auto-resize script is a few kilobytes and loads without blocking anything.
Does it handle low-voltage DC systems like solar or 12V battery banks?
Yes — source voltage and circuit type (single-phase/DC vs. three-phase) are both adjustable, so it works for 12V/24V DC runs as well as 120/240V AC and three-phase.
Does it account for continuous loads?
Yes — a "continuous load" checkbox applies the NEC-required 125% ampacity adjustment for loads running 3+ hours.
Can I resize it or set a fixed width?
Yes. Choose a responsive (100%) or a fixed-pixel width when you copy the code; the height auto-fits the calculator, with a fixed fallback if the resizer script is blocked.
Just need to run the numbers yourself? Use the full Wire Size Calculator — it has the formulas, a worked example and an FAQ. Or see all embeddable calculators.