Free Converters Tools & Calculators
Browse 349+ free interactive converters calculators, estimators, and utilities. 100% free, private, and runs directly in your browser without signup.
Roman to Integer Converter — Convert Roman Numerals to Numbers (Free)
Decode Roman numerals to numbers free: strict validator, step-by-step breakdown, batch mode, and overline (vinculum) support to 3,999,999. 100% private.
SAE to Metric Calculator — Wrench, Socket & Bolt Size Conversion
Convert SAE (fractional inch) sizes to metric millimeters and back. Wrench/socket interchange chart with fit ratings, SAE bolt diameter + UNC/UNF thread pitch reference, and worked examples. 100% free, runs offline in your browser.
Scale Model Lab — Scale Model Conversion Suite (1:72, HO, N, Rescale %, Printable Ruler)
Free scale model conversion suite: real↔model converter with hobby presets (HO 1:87, N 1:160, 1:72, 1:48, 1:35, dollhouse 1:12), what-scale identifier, between-scale rescale %, fractional-inch output, printable scale ruler, model train scale speed, size comparison & paint mixer. 100% client-side.
Scuba Air Lab — SAC Rate Calculator, Gas Planning & Tank Guide
Free scuba gas planning suite: SAC rate calculator (metric + imperial), RMV converter, cylinder database (AL80, HP100, LP85, steel 12/15/18L, twinsets), gas planner with rule of thirds, rock-bottom / turn pressure, dive-time estimator and tank fill calculator. 100% client-side, no signup.
Ski Length Calculator — Height, Weight, Skill, Poles, Boots & DIN
Free ski length calculator: height, weight, skill level and ski type to ski length, plus kids ski sizer, pole length, boot mondo converter, DIN reference and effective edge explainer.
Snake to Pascal Converter
High-Performance Snake Case to Pascal Case Converter, Identifier Transformer, and Code Case Formatter with 100% SEMrush keyword optimization.
Snow Load Calculator — ASCE 7-22 Roof Snow Loads
Free ASCE 7-22 snow load calculator: flat roof pf, sloped roof ps with Cs, drift, unbalanced loads, psf to kPa converter.
Sobriety Calculator — Days Sober Counter, Milestone Chips & Money Saved
Free sobriety calculator and live days-sober counter. Enter your quit date to see your sober time ticking live, milestone chip timeline (24 hours, 30/
Specific Impulse Calculator
Compute specific impulse (Isp) from thrust and mass flow rate, convert Isp to exhaust velocity, calculate total impulse and density impulse. Verified
Speed Converter — MPH, KM/H, M/S, Knots, Mach
Free online speed converter: convert mph, km/h, m/s, knots, ft/s, Mach and fractions of light speed live, with running pace mode and real-world speed comparisons. 100% client-side.
Sql To Csv
Extract data from SQL Insert statements into CSV.
Square Feet Converter - Convert ft² to m², Acres, Hectares and More
Free square feet converter: convert ft² to square meters, acres, square yards, hectares, square miles and 4 more area units. Exact constants, worked examples, 2-way.
Square Feet to Cubic Feet Calculator - Area to Volume with Depth
Convert square feet to cubic feet: enter your area in square feet and a depth or thickness, and get the volume in cubic feet, cubic yards, cubic meters, and gallons. Includes a reverse depth finder and concrete/mulch presets.
Square Feet to Cubic Yards Calculator
Convert square feet to cubic yards: enter area and depth to get cubic yards, cubic feet, bag counts for mulch or soil, waste allowance, and a reverse depth mode. Free, no signup.
Storage Unit Size Calculator — What Size Do I Need? (5×5 to 10×30)
Storage unit size calculator: what size do I need? Estimate from 120+ household items with a 10-20% buffer, stacking planner and climate-control advic
String Compare & Text Diff Tool
High-performance online string compare and text diff tool. Compare two strings, find differences between texts, and perform word-to-word comparison online.
String to Snake Case
Universal Convert String to Snake Case Tool, Naming Convention Transformer, and Identifier Sanitizer with 100% SEMrush keyword optimization.
String To Json
Sunroom Size Calculator — 7 Ways to Plan Your Sunroom
How big should a sunroom be? Free 7-mode calculator for glazing %, HVAC BTU per sq ft, foundation cost, permits, setbacks and furniture layout.
SVG Code to File – SVG Viewer, Converter & Editor
Online SVG code to file converter and viewer. Paste SVG code, preview it live, download as .svg file, convert to PNG/Base64, and explore React/React Native SVG usage.
Free SVG Converter & Vector Creator
Interactive raster image to SVG converter, transforming PNG, JPG, and logos into scalable vector graphics with full color support.
SVG to Code Converter & Vector Component Generator
Free online SVG to code converter. Convert any SVG document into React JSX, React Native, inline HTML SVG, and CSS Data URI. Learn how to create an SVG file, extract SVG from developer tools, and download SVG code to SVG file.
SVG to JSX & React Component Converter
Standalone professional SVG to JSX converter, React SVG transformer, and React Native SVG component builder. Convert SVG code to React component with clean camelCase attributes and zero AI slop.
SWG to mm Converter — SWG to mm² Wire Gauge Calculator | nrtechstudio
Convert SWG to mm, mm², inches and circular mils (7/0–50), reverse-convert mm/mm² to SWG, browse the full searchable SWG table with reference ampacity, and size wire with a 3% voltage-drop advisor. 100% client-side.
SWR Lab — SWR Calculator, Impedance Matching & Balun Designer
Free SWR lab suite: SWR ↔ return loss ↔ reflection coefficient converter, SWR-adjusted coax loss calculator, L-network impedance matching calculator, toroid turns designer, ugly-balun & ferrite choke advisor, mismatch loss calculator. 100% private, runs in your browser.
T/E2 Ratio Calculator — Testosterone to Estradiol Ratio + Unit Converter
Calculate your testosterone-to-estradiol (T/E2) ratio with automatic unit conversion (ng/dL ↔ nmol/L, pg/mL ↔ pmol/L), reverse calculator for target r
Temperature Converter — °C, °F, K, °R, °Ré + Oven & Gas Mark Chart
Free temperature converter: convert Celsius, Fahrenheit, Kelvin, Rankine and Réaumur instantly — all five scales at once. Includes oven temperature conversion, UK gas mark chart, fan vs conventional guide, and formulas.
Tennis Racket Grip Size Calculator — Ruler Test, Finger Test & US/EU Converter
Free tennis racket grip size calculator: ruler test, finger test, US/EU converter, overgrip adjuster, junior sizer and regrip advice.
Text To Hex
Convert ASCII text to hexadecimal format.
Thermal Conductivity Calculator: Fourier's Law, R-Value & Unit Converter | nrtechstudio.com
Free thermal conductivity calculator: solve Fourier's law q = k·A·ΔT/L in four directions, compute thermal resistance R = L/(k·A) for series and paral
Thermal Diffusivity Calculator: α = k/(ρ·cp), Materials Table & Unit Converter | nrtechstudio.com
Free thermal diffusivity calculator: solve α = k/(ρ·cp) four ways, compare 26 materials (copper 116.2, aluminum 97.9, air 21.5, water 0.1434 x10^-6 m2
Thermal Energy Calculator - Sensible Heat Q = mcT, Latent Heat and Units
Free thermal energy calculator: solve sensible heat Q = m*c*delta-T in all 4 directions, latent heat Q = m*L, power-time energy Q = P*t, and convert J
Tire Size Calculator & Comparison — Speedometer Error, Will-It-Fit & Visualizer (Free)
Free tire size calculator and comparison tool: compare two tire sizes side by side, calculate speedometer & odometer error, revolutions per mile, gear ratio effect, will-it-fit verdict, visual overlay, load index & speed rating charts. Metric, flotation, motorcycle & bicycle sizes. 100% client-side, no signup.
TV Stand Size Calculator — Width, Height & Depth for Any TV
TV stand size calculator: match stand width, height & depth to your TV. 7 free modes — width, height, corner fit, depth, cabinet opening. Inches + cm.
Text to Binary & ASCII Converter Online
Free online text to binary ascii converter, binary ascii converter, and ascii binary translator online. Convert binary to string, ascii code to binary, and translate binary to ascii.
URL Encoder Online - URL Parameter Encoder Tool
Free online URL encoder and URL encode converter. Encode URL online, URL parameter encoder, URL encoder encode, online urlencoder, and online query string encoder tool.
UTF-8 Encoder & Decoder Online
Free online UTF-8 encoder decoder, unicode decoder, and UTF-8 converter. Encode and decode UTF-8 byte sequences, UTF-8 to ASCII, and unicode character codes.
VA to kVA Calculator — Convert VA, kVA & MVA
Free VA to kVA calculator: convert apparent power between VA, kVA, and MVA instantly, both ways. Includes a VA vs watts explainer (power factor), worked examples, and UPS/generator sizing context. 100% client-side — your numbers never leave your browser.
Video & WhatsApp Link Generator
Free online video link generator, WhatsApp short link maker, and hyperlink tool. Convert URL to hyperlink, create web links, and generate embed codes.
Volts to Joules Calculator | Electrical Energy from Voltage
Convert volts to joules: E = V x I x t (power times time), E = V x Q for batteries (mAh to joules), and capacitor energy 1/2 CV squared. Free calculator with kJ and Wh results.
Volts to Ohms Calculator — Ohm's Law Lab (V=IR Solver, Divider, Power Rating)
Free volts to ohms calculator: solve R from V and I, full Ohm
Volume Converter - Liters, Gallons, mL, Cups, Cubic Feet & More
Free volume converter: liters to gallons, mL, cups, fl oz, cubic feet and more. Live two-way results, batch mode, exact US/UK gallon factors. 100% client-side.
WebVTT to SRT Converter & Subtitle Tool
Standalone professional VTT to SRT converter, online SRT to VTT converter, and WebVTT to SubRip subtitle converter. Convert VTT to TXT, convert VTT to Word, and vtt转srt with zero AI slop.
Watch Accuracy Lab — Track & Interpret Mechanical Watch Accuracy (Free)
Free watch accuracy lab: track seconds-per-day with an accuracy tracker, per-position ISO-style worksheet, COSC/METAS standards checker, timegrapher reading interpreter, BPH/Hz converter, magnetism guide & power-reserve estimator. 100% client-side.
Water Density Calculator — ρ vs Temperature (Kell 1975 Formula)
Free pure water density vs temperature calculator: Kell (1975) formula, maximum-density point 4 °C, specific weight, kg/m³ ↔ lb/ft³ conversion, and mass from volume. 100% client-side.
Watts to Lux Calculator — Convert Bulb Watts to Room Lux
Free watts-to-lux calculator: enter bulb watts + bulb type (efficacy lm/W) + room area (m² or ft²) to get lux. Reverse mode: target lux → watts needed. Worked examples, efficacy table, room lux targets.
Web Scraping & HTML Extractor Studio
The ultimate Web Scraping tool, HTML Scraper, Link Extractor, and Text to HTML Converter with 100% SEMrush keyword optimization.
Weight to Mass Converter & Physics Gravity Studio
Interactive weight to mass converter, conversion of weight to mass, and pounds to mass conversion for physics students and engineers.
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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.