Percentage Calculator
A little math. A lot less effort.
A LITTLE LESS BUSYWORK
Your everyday tools.
All in one place.
Resize an image. Run the numbers. Clean up your text.
Useful tools for the little things that get in your way.
Free to useBrowser toolsBrowser-based
Start with the essentials
A good place to begin ↙Explore your toolkit
Age Calculator
Calendar age, elapsed days and your next birthday.
Date Calculator
Add days, subtract days, or compare two dates.
Unit Converter
Convert length, mass, volume and eight more measures.
QR Generator
Static URL, text, Wi-Fi and UPI codes. PNG or SVG.
EMI Calculator
Monthly loan payments with a repayment schedule.
SIP Calculator
Project regular monthly contributions with clear assumptions.
Compound Interest Calculator
See how principal grows with periodic compounding.
Simple Interest Calculator
Calculate interest without compounding.
GST Calculator
Add or extract GST with CGST/SGST or IGST breakdown.
VAT / Sales Tax Calculator
Add or extract a tax rate you specify.
Profit Margin Calculator
Compare profit margin and markup.
Markup Calculator
Set a selling price from cost and markup.
Break-even Calculator
Find how many units cover your fixed costs.
Invoice Generator
Invoices, quotations and receipts with local PDF export.
GST Invoice Generator
Indian GST fields, line taxes and a reviewed PDF preview.
Percentage Calculator
Find percentages, without the mental math.
Word Counter
Words, characters, and bytes at a glance.
Resize Image
Set new dimensions. Keep the right proportions.
JSON Formatter
Turn messy JSON into something readable.
Signature Resizer
Crop your signature. Set dimensions. Check readability.
Resize Image in KB
Meet a file size limit. Verify every byte.
Compress Image
Reduce JPG size with adjustable quality.
Discount Calculator
See what you save and what you pay.
Days Between Dates
Calculate the gap between two dates.
Temperature Converter
Convert Celsius, Fahrenheit, and Kelvin.
Case Converter
Switch between upper and lowercase.
Remove Duplicate Lines
Clean up your lists in one click.
URL Encoder / Decoder
Encode and decode URL components.
Merge PDF
Combine documents into one tidy PDF.
Split PDF
Keep just the pages you need.
Images to PDF
Bring your images together in a document.
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Keep it simple. Keep it yours.
The current tools process inputs in your browser. No account is needed; files are handled in the browser.
About RedTools
How RedTools works: free browser utilities, local processing, reviewed examples and clear limits.
Useful tools for everyday work
RedTools is an independent utility project for image preparation, PDF basics, calculations, text and business documents. It requires no account. Only working tools appear in the main catalog; upcoming features are labeled.
How results are produced
The tool pages explain the input, a worked example and output limitations. Images, PDFs, QR payloads and calculation inputs are processed in your browser using shared engines. Downloads are generated locally. Financial calculations are estimates based on the entered assumptions, and invoices need review against your own requirements.
Project review
The current tools and invoice layouts were reviewed on 6 October 2026. Tests cover calendar boundaries, arithmetic, invoice tax rounding, QR decoding and output limits. A tested example is evidence for that example; it is not a promise that every document or browser is compatible.
Independent and open about limits
RedTools is not affiliated with a government agency. Application rules and tax requirements can change. Check the requirements supplied by the receiving organization and seek appropriate professional advice for decisions that need it.