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Embed the Roam Wired calculators

Five free campervan electrical calculators you can drop straight into a blog post. Pick the one that matches what you've written, copy the snippet, paste it into your HTML. That's it.

What you should know:

  • No external scripts, fonts or trackers — nothing loads from anywhere but roamwired.com.
  • loading="lazy" by default, so it costs you nothing on page speed.
  • Follows your reader's light or dark theme, and works down to 320px wide.
  • No signup wall, no email capture, no affiliate links inside the tool.
  • Free to use permanently. The only ask is that the one-line credit underneath the tool stays — that's the whole cost, and it's why I can keep these free.
Market:
mm², metres, UK sun hours

Solar Panel Calculator

Sizes an array from daily usage, then shows what it actually generates in summer, on average, and in deep winter. The seasonal split is the part no other calculator shows.

Best for posts about: Solar, off-grid power, "how much solar do I need"

<iframe src="https://roamwired.com/embed/tools.html?tool=solar"
        title="Campervan Solar Panel Calculator"
        style="width:100%;max-width:680px;height:780px;border:0"
        loading="lazy"></iframe>
<p style="max-width:680px;margin:6px 0 0;font-size:14px">
  Solar calculator by <a href="https://roamwired.com/guides/campervan-solar-setup">Roam Wired</a>
</p>

Battery Size Calculator

Daily watt-hours to a buyable bank size, accounting for depth of discharge — and shows how much smaller the lithium equivalent would be.

Best for posts about: Leisure/house batteries, lithium vs AGM

<iframe src="https://roamwired.com/embed/tools.html?tool=battery"
        title="Campervan Battery Size Calculator"
        style="width:100%;max-width:680px;height:660px;border:0"
        loading="lazy"></iframe>
<p style="max-width:680px;margin:6px 0 0;font-size:14px">
  Battery calculator by <a href="https://roamwired.com/guides/campervan-battery-guide">Roam Wired</a>
</p>

Power Consumption Calculator

Appliance-by-appliance power audit with real defaults, including inverter losses on AC loads. The natural entry point for any van electrical post.

Best for posts about: Power audits, general van conversion guides

<iframe src="https://roamwired.com/embed/tools.html?tool=power"
        title="Campervan Power Consumption Calculator"
        style="width:100%;max-width:680px;height:780px;border:0"
        loading="lazy"></iframe>
<p style="max-width:680px;margin:6px 0 0;font-size:14px">
  Power consumption calculator by <a href="https://roamwired.com/calculator">Roam Wired</a>
</p>

Wire Size & Fuse Calculator

Cable size, fuse rating and voltage drop for a single circuit. Steps the cable up when no standard fuse would protect it.

Best for posts about: Wiring, cable sizing, fusing, electrical safety

<iframe src="https://roamwired.com/embed/tools.html?tool=wire"
        title="Campervan Wire Size & Fuse Calculator"
        style="width:100%;max-width:680px;height:700px;border:0"
        loading="lazy"></iframe>
<p style="max-width:680px;margin:6px 0 0;font-size:14px">
  Wire size &amp; fuse calculator by <a href="https://roamwired.com/calculator">Roam Wired</a>
</p>

Battery Runtime Calculator

How long a bank actually runs a given load, using usable capacity rather than the nameplate figure.

Best for posts about: "Can I run a fridge / CPAP / laptop off my battery"

<iframe src="https://roamwired.com/embed/tools.html?tool=runtime"
        title="Campervan Battery Runtime Calculator"
        style="width:100%;max-width:680px;height:660px;border:0"
        loading="lazy"></iframe>
<p style="max-width:680px;margin:6px 0 0;font-size:14px">
  Battery runtime calculator by <a href="https://roamwired.com/guides/campervan-battery-guide">Roam Wired</a>
</p>

Optional: auto-height

The heights above are set to fit each tool. If you'd rather the iframe resize itself as the reader changes inputs, paste this once anywhere on the page.

<script>
window.addEventListener('message', function (e) {
  if (!e.data || !e.data.rwEmbedHeight) return;
  document.querySelectorAll('iframe[src*="roamwired.com/embed"]').forEach(function (f) {
    if (f.contentWindow === e.source) f.style.height = e.data.rwEmbedHeight + 'px';
  });
});
</script>

Accuracy

Every figure comes from the same engine that powers the full Roam Wired design tool — cable sizing to a 1.25× continuous-duty rating, voltage drop calculated over the full out-and-back run, and fuses sized so they always protect the cable rather than the appliance. UK sizing uses thin-wall and Hi-Flex cable ratings; US sizing uses stocked AWG sizes with ABYC-style ampacities.

These are planning tools, not a substitute for a qualified auto electrician — component manuals always take precedence.

Want something that isn't here?

If there's a calculation your readers keep asking about that these don't cover, just reply to my email and I'll look at building it.