Free Online Tools & Honest Software Reviews

Fast, free calculators, checkers and generators — no signup, no clutter. Plus in-depth reviews of the software behind them.

100% FreeNo SignupRuns in Your Browser

Popular Tools

Our most-used free tools. Everything runs in your browser — nothing is uploaded.

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Word Counter

Count words, characters, reading and speaking time — plus platform limit checks.

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JSON Formatter & Validator

Format, validate and inspect JSON in your browser.

Coming soon
Σ

GPA Calculator

Calculate your grade point average in seconds.

Coming soon
A+

Final Grade Calculator

Find the final exam score you need for your target grade.

Coming soon
☾

Sleep Cycle Calculator

Find the best bedtime or wake-up time based on sleep cycles.

Coming soon
$

PayPal & Stripe Fee Calculator

See exactly what payment processors take from each sale.

Coming soon

Browse by Category

Every tool we’re building, grouped by what it does.

Review Tools

  • Star Rating Calculator
  • Negative Review Reply Generator
  • Review Request Generator
  • Google Review QR Generator

Student Calculators

  • GPA Calculator
  • Final Grade Calculator
  • Citation Generator

Developer Tools

  • JSON Formatter
  • Regex Tester
  • JWT Decoder
  • Cron Explainer

Fee & Money Calculators

  • PayPal & Stripe Fee Calculator
  • Etsy Fee Calculator
  • eBay Fee Calculator
  • Pay Stub Generator
  • Rent vs Buy Calculator

Everyday Calculators

  • Sleep Cycle Calculator
  • Pregnancy Due Date Calculator
  • TDEE & Macro Calculator
  • Wedding Budget Calculator

SEO & Website Checkers

  • Meta Tag Analyzer
  • WHOIS Lookup
  • SSL Checker
  • True Hosting Cost Calculator

Business & Creator Tools

  • Word Counter
  • YouTube Money Calculator
  • Hashtag Generator
  • Username Generator

Why ReviewKarts

Built for people who want answers, not accounts.

Private by design

Our tools run 100% in your browser — private, with nothing uploaded.

No signup walls

No accounts, no clutter — just fast, free tools that work.

Reviewers behind the tools

Built by the same team that reviews software for a living.

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In-depth, honest reviews of hosting, SEO tools and software.

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Frequently Asked Questions

Are the tools free?

Yes, completely.

Do I need an account?

No, no signup.

Is my data stored?

No — tools run in your browser; nothing you type is uploaded.

Who runs ReviewKarts?

An independent site publishing free tools and honest software reviews.