Free calculators for your website

Add any of our 23 calculators to your blog, store or community site. They are free, need no sign-up, work on phones and resize themselves to fit your page.

How to add a calculator

1. Choose a calculator above and click Copy embed code.
2. Paste it into your page as HTML. In WordPress, add a Custom HTML block; in Squarespace or Wix, use an Embed or Code block.
3. Publish. The calculator adjusts its height automatically and works on mobile.

Questions

• Is it really free? Yes. There is no sign-up, no API key and no usage limit.
• Does it collect my visitors' data? No. Calculations run in the visitor's browser and nothing they type is sent anywhere. See our privacy policy.
• Can I remove the credit line? The small "by WattWise" link under the calculator is appreciated but not required.
• What if the calculator doesn't resize? Some site builders strip the small script in the code. The calculator still works; set the iframe's height to fit.
• Want a calculator we don't have? Tell us — requests shape what we build next.