About
About this site
Karu Tools is a free collection of browser-based utilities for small everyday and work tasks such as character counting, date calculation, JSON formatting, and bill splitting. The site focuses on tools that open quickly, require no sign-up, and process input locally in the browser whenever possible.
Who it is for
Individuals, students, workers, and developers who need quick checks for text, dates, amounts, or data formats.
What it covers
Browser-based calculation, conversion, formatting, random selection, and checklist tools.
What it does not cover
The site does not provide professional medical, legal, tax, or financial advice. For important decisions, check official sources or a qualified professional.
Tool categories
Choose the category closest to your task to find the right tool faster.
Text
Tools for counting, cleaning, and normalizing writing, lists, form input, and text copied from spreadsheets or CSV data.
View toolsDate and time
Tools for date calculation, day counts, age checks from a birth date, and Japanese era names.
View toolsDeveloper and data
Utilities for JSON, URLs, Base64, UUIDs, HTML escaping, password generation, and quick data checks during development.
View toolsLottery and decisions
Tools for choosing from candidates, drawing lots, deciding order, and making balanced teams locally in the browser.
View toolsEveryday
Tools for everyday calculations such as bill splitting, tax, discounts, BMI, wages, packing lists, cooking measures, and room area.
View toolsMusic and audio
Tools for tempo checks, rhythm practice, BPM measurement, and simple audio-assisted music practice.
View toolsInput handling
As a general rule, tool input is processed only in your browser. If a future tool uses an external API, storage, or login feature, that behavior will be stated on the relevant page and in the privacy policy.
Read the privacy policyOperation and contact
Operator: Karu Tools Team
You can use the contact page to report bugs, incorrect wording, or improvement ideas. Submitted information is used only as needed to reply or confirm the issue.