Tip & Bill Split Calculator
Split a bill with tip and rounding options.
For site owners
Embeddable calculator widgets
Drop a working BoringToolsKit calculator into any page with one iframe. Free, no signup, no API key — calculations run in the visitor's browser and each widget links back to the full tool with its methodology.
Live widgets
BMI Calculator
Body-mass index with CDC adult categories.
Compound Interest Calculator
Project growth with compounding and contributions.
Percentage Calculator
Percent of, change, and difference instantly.
Age Calculator
Exact age in years, months, and days.
Calorie Calculator
Maintenance calories from age, sex, height, weight, activity.
How to embed
Copy the iframe snippet from any preview, or build your own embed from the shared widget URL pattern:
<iframe src="https://boringtoolskit.com/embed/<tool-slug>/" width="100%" height="640" style="border:1px solid #ccc;border-radius:12px" title="Calculator widget"></iframe>Every embeddable tool is methodology-verified, keeps inputs on the visitor's device, and discloses its assumptions on the result.