Free Calculator Widgets for Your Website

Add a professional, mobile-friendly finance calculator to your website in about 30 seconds — no signup, no API key, no cost. Copy the embed code, paste it into your page, and the widget resizes itself to fit. Every calculator is maintained against official sources, so your readers always see the current-year rules.

100% freeNo signup or usage limits

Auto-resizingNo scrollbars, fits any layout

Always currentRules updated when laws change

Buddhist Era ↔ Christian Era Converter

Convert Thai Buddhist Era (พ.ศ.) years to and from the Christian/Gregorian calendar (±543). Broad appeal for expat-in-Thailand, travel, genealogy, translation, and history pages.

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<iframe src="https://www.kalberry.com/embed/buddhist-era-converter" title="Buddhist Era ↔ Christian Era Converter by Kalberry" loading="lazy" style="width:100%;max-width:480px;height:380px;border:1px solid #e5e7eb;border-radius:12px"></iframe>
<p style="font-size:12px;color:#6b7280;max-width:480px">Buddhist Era date converter by <a href="https://www.kalberry.com/en/tools/buddhist-era-converter?utm_source=embed&utm_medium=widget_link&utm_campaign=buddhist-era-converter">Kalberry</a>.</p>
<script>window.addEventListener("message",function(e){if(e.data&&e.data.type==="kalberry-embed-height"){var f=document.querySelector('iframe[src="https://www.kalberry.com/embed/buddhist-era-converter"]');if(f)f.style.height=e.data.height+"px";}});</script>

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Compound Interest Calculator

Let readers project investment growth with monthly contributions and compare compounding frequencies.

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Embed code

<iframe src="https://www.kalberry.com/embed/compound-interest" title="Compound Interest Calculator by Kalberry" loading="lazy" style="width:100%;max-width:480px;height:560px;border:1px solid #e5e7eb;border-radius:12px"></iframe>
<p style="font-size:12px;color:#6b7280;max-width:480px">This free compound interest calculator is provided by <a href="https://www.kalberry.com/en/tools/compound-interest-calculator?utm_source=embed&utm_medium=widget_link&utm_campaign=compound-interest">Kalberry</a>.</p>
<script>window.addEventListener("message",function(e){if(e.data&&e.data.type==="kalberry-embed-height"){var f=document.querySelector('iframe[src="https://www.kalberry.com/embed/compound-interest"]');if(f)f.style.height=e.data.height+"px";}});</script>

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Thailand Income Tax Calculator

Thai personal income tax for 2026 with deductions and the progressive bracket table — ideal for Thai finance and expat blogs.

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Embed code

<iframe src="https://www.kalberry.com/embed/income-tax" title="Thailand Income Tax Calculator by Kalberry" loading="lazy" style="width:100%;max-width:480px;height:620px;border:1px solid #e5e7eb;border-radius:12px"></iframe>
<p style="font-size:12px;color:#6b7280;max-width:480px">Thailand income tax calculator by <a href="https://www.kalberry.com/en/thailand/income-tax-calculator?utm_source=embed&utm_medium=widget_link&utm_campaign=income-tax">Kalberry</a> — updated for 2026.</p>
<script>window.addEventListener("message",function(e){if(e.data&&e.data.type==="kalberry-embed-height"){var f=document.querySelector('iframe[src="https://www.kalberry.com/embed/income-tax"]');if(f)f.style.height=e.data.height+"px";}});</script>

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Thailand Severance Pay Calculator

Statutory severance under the Labour Protection Act (Section 118) — perfect for HR, legal, and expat resources.

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Embed code

<iframe src="https://www.kalberry.com/embed/severance-pay" title="Thailand Severance Pay Calculator by Kalberry" loading="lazy" style="width:100%;max-width:480px;height:600px;border:1px solid #e5e7eb;border-radius:12px"></iframe>
<p style="font-size:12px;color:#6b7280;max-width:480px">Thailand severance pay calculator, courtesy of <a href="https://www.kalberry.com/en/thailand/severance-pay-calculator?utm_source=embed&utm_medium=widget_link&utm_campaign=severance-pay">Kalberry</a>.</p>
<script>window.addEventListener("message",function(e){if(e.data&&e.data.type==="kalberry-embed-height"){var f=document.querySelector('iframe[src="https://www.kalberry.com/embed/severance-pay"]');if(f)f.style.height=e.data.height+"px";}});</script>

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How to embed a calculator on your site

Copy the embed code for the calculator you want using the button above.
Paste it into your page. In WordPress, use a "Custom HTML" block. In Wix, Squarespace, Ghost, or Webflow, use the HTML / embed element. In hand-coded sites, paste it directly into your HTML.
Publish. The widget appears immediately and resizes itself to fit — no scrollbars, no maintenance. When the underlying tax or labour rules change, your embedded widget updates automatically.

The embed code includes a small "Powered by Kalberry" attribution link. Please keep it — it is the only thing we ask in return for a free, maintained, mobile-friendly tool.

Frequently asked questions

Are these calculator widgets free to embed?

Yes. Every Kalberry calculator widget is completely free to embed on any website, blog, or intranet. There is no signup, no API key, and no usage limit. We only ask that you keep the small attribution link that comes with the embed code.

How do I add a calculator to my website?

Copy the embed code for the calculator you want and paste it into your page HTML where you want the tool to appear. It works in WordPress (Custom HTML block), Wix, Squarespace, Ghost, Webflow, and any site that allows an HTML/embed block. The widget resizes itself automatically so it never shows a scrollbar.

Will the widget slow down my site?

No. The widget loads in an iframe with loading="lazy", so it only loads when the reader scrolls near it. It is a lightweight, self-contained page with no heavy frameworks, so it has virtually no impact on your page speed or Core Web Vitals.

Do I have to keep the "Powered by Kalberry" link?

Yes, please keep the attribution link in the embed code. It is how the tool stays free — it is the only thing we ask in return. The link also tells your readers the calculation is backed by a maintained, up-to-date source.

Are the Thai tax and severance figures kept up to date?

Yes. The Thai income tax brackets, deductions, social security ceiling, and severance rules are maintained against official sources (the Revenue Department, Social Security Office, and Labour Protection Act) and updated when the law changes. Embedding the widget means your readers always see the current-year rules without you having to update anything.