Free Online Tools
That Just Work
Work out your take-home pay, size up a loan, shrink a photo that’s too big to email, or turn a PDF into exactly what you need. 33 free calculators and converters — no ads in your way, no account, and your files never leave your device.
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The four tools people open most — money questions, and photos that are too big to send.
Salary Calculator
See exactly what lands in your bank account after tax.
Loan Calculator
Monthly payment, total interest, and the full payoff schedule.
Image Compressor
Shrink photos up to 95% without a visible quality drop.
Fuel Cost Calculator
Compare petrol, diesel, CNG, and EV running costs side by side.
All 20 everyday tools, grouped by what you need
Every one runs entirely in your browser, opens instantly, and asks for nothing — no email, no upload, no watermark.
Money & Finance
10 toolsWork out what you earn, owe, and pay — before you sign anything.
Salary Calculator
Convert your pay between hourly, weekly, bi-weekly, semi-monthly, monthly, and annual — and see your estimated take-home pay after income tax and social contributions. Country presets for the US, UK, Canada, Australia, and India with current tax rules. 100% private.
Loan Calculator
Calculate the monthly payment, total interest, total cost, and full amortization schedule for any personal or auto loan. See how an extra monthly payment cuts interest and payoff time. Multi-currency (USD, GBP, EUR, CAD, AUD, INR).
Loan Comparison
Compare two or three loan offers side by side and rank them by what they really cost — total interest plus every fee — with an effective APR that accounts for fees. Multi-currency, 100% private.
Mortgage Calculator
Estimate your monthly mortgage payment with a full PITI breakdown — principal, interest, property tax, insurance, PMI, and HOA. See total interest, payoff date, an amortization schedule, and how extra principal payments save. 100% browser-based.
Compound Interest
Calculate compound interest and investment growth with optional monthly or annual contributions, any compounding frequency, and multiple currencies. See final balance, total interest, and a year-by-year table.
Fuel Cost Calculator
Compare the real running cost of Petrol, Diesel, CNG, and Electric (EV) for the same driving — broken down by day, week, month, and year. Country presets for the US, UK, Canada, Australia, India, and Germany with editable local prices. Multi-currency, 100% private.
EMI Calculator
Calculate home loan, car loan, or personal loan EMI with full repayment schedule. Add part payments to see interest saved and tenure reduced. 100% browser-based.
Income Tax
Calculate income tax for FY 2025-26 (AY 2026-27). Compare old vs new tax regime instantly. Includes standard deduction, 80C, HRA, and all major deductions for salaried Indians.
GST Calculator
Calculate GST instantly — add GST or extract GST from inclusive amounts. Supports the GST 2.0 slabs (0%, 5%, 18%, 40%) with CGST/SGST/IGST split. Free and Indian-business friendly.
Amount to Words
Convert amounts to words for cheques, invoices, and legal documents. Supports USD, INR, EUR, GBP with Lakhs and Crores.
Everyday & Health
4 toolsQuick answers for dates, ages, health numbers, and time.
BMI Calculator
Calculate your Body Mass Index instantly. Supports metric (kg/cm) and imperial (lbs/ft) units. See BMI category, healthy weight range, and ideal weight for your height.
Age Calculator
Calculate exact age in years, months, and days from any date. See total months, weeks, days, hours, and minutes lived. Perfect for documents, birthdays, and milestones.
Date Difference
Calculate days, weeks, months, and years between two dates. Add or subtract days from a date. Perfect for project planning, deadlines, and event countdowns.
Time Converter
Convert between 24-hour and 12-hour time formats instantly. Supports bulk conversion and military time.
Photos, Files & Text
6 toolsShrink, convert, count, and create — without uploading anything.
Image Compressor
Compress JPG, PNG, and WebP images up to 95% smaller without visible quality loss. Reduce file size for WhatsApp, email, and websites — 100% browser-based, your photos stay private.
PDF Tools
Merge multiple PDFs into one, split a PDF into pages, or compress PDF size — all in your browser. No uploads, no signups, completely private and free.
QR Code Generator
Generate QR codes for URLs, text, WiFi, email, and phone numbers. Customize colors and size, then download as PNG.
Word Counter
Count words, characters, sentences, and paragraphs. See reading time, speaking time, and keyword density.
Color Picker
Pick colors and convert between HEX, RGB, HSL, and CMYK formats. Check contrast ratios for accessibility.
Embroidery Viewer
Preview DST embroidery design files online. View stitch patterns, colors, dimensions, and download as PNG or PDF.
Want a Loan at a Lower Interest Rate?
Home · Personal · Car · Education · Business · Gold. Our free guide explains what actually sets your rate, how to compare banks & NBFCs on total cost — not the headline number — and how to check any offer with free calculators.
Writing code instead? 17 developer tools live over here.
JSON, YAML and CSV converters, a regex tester, a diff checker, an in-browser API client, hashes and Base64 — the same privacy rules, nothing uploaded, no sign-up.
Nothing Leaves Your Device
Your salary, your photos, your documents — everything is processed on your own machine. There is no upload step, because there is no server to upload to.
Instant, Every Time
No queues, no "processing…" spinner, no waiting for a download link by email. Results appear as fast as you can type, even on a slow connection.
Explained, Not Just Calculated
Every calculator comes with a plain-English guide, worked examples, and reference tables — so you understand the answer, not just read it.
Why use StringToolsApp?
Most online tools make you pay for the privilege of being interrupted. You search for something simple — how much a job offer is really worth after tax, or how to get a holiday photo under an email attachment limit — and land on a page buried in pop-ups that wants your email address before it will show you an answer. Worse, plenty of them ask you to upload the file first, which means your payslip or passport scan has just been copied onto somebody else’s server.
StringToolsApp works the other way round. Every tool here runs entirely inside your own browser using modern web technology, so the numbers you type and the files you open stay on your device. Nothing is uploaded, nothing is stored, and closing the tab is all it takes to erase it. That is also why the tools are fast: there is no round trip to wait for.
We also think a calculator that only spits out a number is half a tool. Each page pairs the working tool with a genuine guide — how the maths actually works, worked examples, reference tables, and honest notes about what the result does not include. Whether you need a take-home pay calculator, a loan calculator, an image compressor, or PDF tools, the goal is that you leave understanding the answer.
Building something instead? The developer tools section has the JSON, YAML, regex, diff, hashing, and API utilities — same rules, same privacy, no sign-up.