About Haru Tools

What we make

Haru Tools is a free collection of small utilities for dates, percentages, writing, and everyday comparisons. English and Korean pages use the same underlying calculations. No account is required.

Answers you can inspect

Each tool explains its input units, formula, worked example, and limitations. Results are general references, not legal, medical, or financial advice. Where conventions differ, such as a leap-day birthday, the tool states its chosen rule.

Editing and checks

Our explanations and guides are written for this site with automated authoring assistance. Calculation code is checked against known examples and edge cases, including leap years, Unicode text, and split remainders. Corrections should identify the input, expected result, and actual result so that both the formula and explanation can be reviewed.

How the site is supported

Display advertising is not enabled. Visitor analytics is optional, and Google Analytics loads only after you accept.

Analytics you can choose

Analytics is optional in every region. Before acceptance, we do not load Google Analytics or send analytics requests. Declining does not change the tools, and Analytics settings in the footer lets you change your choice.