Free Converters Tools & Calculators
Browse 349+ free interactive converters calculators, estimators, and utilities. 100% free, private, and runs directly in your browser without signup.
Weird Lettering Generator – Fancy Fonts & Text Shrinker
Weird lettering generator, letter generator, shrink a text, make the text smaller, lower to uppercase converter.
WhatsApp QR Generator & Chat Link Maker
Interactive WhatsApp QR code generator, Click-to-Chat link creator, group URL maker, and business message suite.
Words to Number Converter — English Words to Digits
Free words to number converter. Convert English number words to digits: two thousand three hundred forty-five becomes 2345. Hyphens, and, decimals and negatives supported. 100% client-side.
Xml To Json
YAML to SQL Converter
Enterprise YAML to SQL Converter, Data Parser, and Database Insert Generator with 100% SEMrush keyword optimization.
YouTube Money Calculator — Estimate Ad Revenue, Shorts & Creator Income
Free YouTube money calculator: estimate monthly ad revenue by niche RPM, Shorts earnings, sponsorships, memberships & merch. Multi-currency, insta
Yurt Size Calculator — 7 Ways to Size Your Yurt
What size yurt do you need? Free 7-mode yurt size calculator: floor area per occupant, 12-30 ft diameters, deck size, insulation, wood stove BTU, layo
Catalytic Converter Replacement Cost Calculator
Estimate catalytic converter replacement cost: OEM vs aftermarket parts, CARB-compliant pricing (CA, CO, ME, NY), theft add-ons, and a repair-vs-scrap verdict.
Feet and Inches Calculator: Add, Subtract, Multiply and Divide
Free feet and inches calculator. Add, subtract, multiply and divide measurements in ft'in
Jeans Size Converter
Convert jeans sizes between US, UK, EU, IT and JP. Enter any size or waist measurement to get every equivalent, plus the right inseam for your height.
Normality Calculator — Normality, Equivalent Weight & N↔M Conversion
Free normality calculator: normality from mass and equivalent weight, equivalent weight from molar mass and n, normality to molarity conversion, and N1V1=N2V2 dilution. 100% client-side, no signup.
Pressure Canning Calculator — Process Times, PSI by Altitude & Batch Planner
Free pressure canning calculator with USDA process times, altitude-to-PSI solver for dial vs weighted gauges, batch planner, and food-safety guardrails.
Subscript Generator - Unicode Subscript Superscript Copy Paste
Convert text to subscript (H₂SO₄) and superscript (x²) Unicode characters. Free copy & paste generator for chemistry, math, Discord, Instagram. No signup.
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How to Use the Tools Directory
Every tool is a single interactive page: enter your inputs, get instant results, no account needed. Use the search box (shortcut: press /) to jump straight to a tool, or browse categories when you are exploring. Each card links to the tool's permanent URL, which you can bookmark or share.
Because all computation happens in your browser, the tools are fast, private, and free forever. If a result looks wrong, use the one-click report control on the tool page so it can be fixed.
Tool Categories at a Glance
| Category | What you will find | Example tasks |
|---|---|---|
| Developer | Encoders, formatters, regex, network tools | Format JSON, test regex, subnet a network |
| Finance | Tax, loans, salary, investing | Estimate tax brackets, amortize a loan |
| Home improvement | Estimators, measurements, materials | Size a wire, estimate paint or flooring |
| Health & fitness | Body metrics, nutrition, workouts | Track BMI, plan calories, score fitness tests |
| Math & science | Converters, geometry, statistics | Convert units, solve triangles |
| Text | Counters, sorters, generators | Count words, alphabetize a list |
| Color | Pickers, converters, checkers | Convert HEX to RGB, check contrast |
| Everyday life | Cooking, travel, automotive, pets | Convert recipes, plan fuel costs |
Popular Tasks and Where to Start
| I want to... | Start with | Why |
|---|---|---|
| Convert between number bases | Binary Converter | Step-by-step base conversion with charts |
| Validate and format data | JSON Formatter | Pretty-print and check JSON instantly |
| Count words for an essay | Word Counter | Words, characters, reading time |
| Check password strength | Password Strength Meter | Entropy-based strength scoring |
| Grade text readability | Readability Score | Flesch-Kincaid and grade levels |
| Audit color contrast | Accessibility Checker | WCAG contrast ratios in one click |
Tools Directory FAQ
What is the NRTechStudio tools directory?
It is a free catalog of more than 2,700 interactive web tools: calculators, converters, generators, and checkers for developers, finance, home improvement, health, education, and everyday tasks.
Are all the tools really free?
Yes. Every tool in the directory is free to use with no sign-up, no trial, and no paywall. They run entirely in your browser.
Do I need to create an account?
No. There are no accounts, logins, or subscriptions. Open a tool and use it immediately.
Is my data private when I use these tools?
Yes. The tools are 100% client-side: your inputs are processed by JavaScript in your own browser and never sent to a server.
How do I find the right tool?
Use the search box at the top of the directory (press / to focus it), or browse by category. Every tool card shows a short description of what it computes.
Do the tools work on mobile?
Yes. The directory and the tools use responsive layouts that adapt to phones, tablets, and desktops.
How many tools are there?
The directory holds more than 2,700 tools and grows regularly as new calculators and converters are published.
Can I request a new tool?
Yes. Each tool page has a report/feedback control you can use to request features or new tools; requests help prioritize what gets built next.
Are the tools accurate?
Calculators use published formulas and reference data (tax tables, NEC ampacity, standard conversions). Each tool page documents its method, and issues can be reported in one click for a fix.
Do tools work offline?
Once a tool page has loaded, most tools keep working without a connection because the logic is client-side JavaScript. The directory search needs the page loaded first.
What categories are covered?
Developer utilities, finance and tax, home improvement, health and fitness, math and science, text tools, color tools, networking, education, and everyday life calculators, among others.
Can I bookmark or share a tool?
Yes. Every tool has its own permanent URL under nrtechstudio.com/tools/, which you can bookmark or share directly.
Is there an API for these tools?
The tools are interactive web pages, not API endpoints. The underlying math is plain JavaScript you can inspect in the page source.
Why do some tools show ratings?
Ratings aggregate user feedback to surface the most trusted tools and flag pages that need fixes or better explanations.
How often are new tools added?
New tools are published on a continuous pipeline, prioritized by measured search demand and by user requests from the feedback controls.
Who builds these tools?
NRTechStudio, an independent tools studio focused on free, private, client-side utilities that respect user privacy.