Free Converters Tools & Calculators
Browse 349+ free interactive converters calculators, estimators, and utilities. 100% free, private, and runs directly in your browser without signup.
Deck Size Calculator — 7 Ways to Size Your Deck
Deck size calculator: 7 modes — guests, furniture zones, yard fit, standard sizes, dining layout, per-person area, house proportion. Free, client-side
Degrees to Radians Converter - Free Online Tool
Free degrees to radians converter and radians to degrees converter. Instant two-way conversion with the formula rad = deg x pi/180, a common-angles table in terms of pi, and worked examples.
Density Altitude Lab — Density Altitude Calculator, TAS & Performance Suite
Free density altitude calculator with humidity correction, pressure altitude, ISA atmosphere model, true airspeed/Mach converter, and Koch-chart takeoff & climb performance estimator. Metric & imperial.
Digits to Words Converter: Spell Numbers in English
Free digits to words converter. Convert digits to words in English: 1234 becomes one thousand two hundred thirty-four. Indian numbering (lakh, crore), USD/INR/IDR currency, check-writing style, decimals and ordinals. 100% client-side.
Dilution Ratio Calculator — Mix Ratios, C1V1, ppm & Cost | nrtechstudio.com
Dilution ratio calculator: mix 1:10, 1:99 and label ratios (bleach, Roundup, Simple Green), C1V1 solver, ratio-to-ppm converter, cost per gallon.
Dive Weight Lab — Scuba Weight Calculator & Buoyancy Suite (Free)
Free scuba weight calculator: how much dive weight you need from body weight, wetsuit thickness, salt vs fresh water, tank type and experience. Plus tank-swing explainer, salt/fresh converter, weight-check protocol, distribution planner and wetsuit buoyancy table. 100% client-side, no signup.
DMS to Decimal Degrees Converter
Free DMS to decimal degrees converter. Convert degrees minutes seconds to decimal degrees, decimal degree to DMS, coordinate degrees minutes and seconds to decimal coordinates.
DMS to Decimal – Degrees Minutes Seconds Coordinate Converter
DMS to decimal, latitude decimal conversion, convert longitude to decimal degrees, lat lon to decimal degrees, degree minutes to decimal degrees, latitude coordinates converter, convert GPS to decimal, degrees min sec to decimal degrees, and more.
Dog Raisin Toxicity Calculator — How Many Raisins Are Toxic to Dogs?
Free dog raisin toxicity calculator: enter your dog
Door Header Size Calculator — Lumber Size, Jack Studs & Span Table | nrtechstudio.com
Door header size calculator: enter the opening width and wall type to get the header lumber size, ply count, jack studs, and overall header length.
Dresser Size Calculator — Width, Height, Depth & Drawer Count
Dresser size calculator: match dresser width to your wall, check standard dimensions, drawer pull-out clearance, and drawer count. Inches and centimet
Drops to mL Converter: How Many Drops in 1 mL
Free drops to mL converter: convert drops to milliliters and back with the USP standard 20 drops/mL factor (plus 15 drops/mL and custom factors). Common conversion table plus guidance for liquid medicine, essential oils, and pharmacy use. Educational tool.
Fast YouTube Embedder & Responsive Video Code Generator
Free fast YouTube embedder and video embed code generator. Create responsive YouTube iframes, embed playlists, configure autoplay, convert YouTube link to embed link, and generate clean HTML/React embed codes.
Engine Displacement Calculator — Bore × Stroke to CI, CC & Liters (Free)
Free engine displacement calculator: enter bore, stroke and cylinder count to get displacement in cubic inches, cc and liters. Includes reverse solver (find bore/stroke/cylinders), bore/stroke ratio, CFM airflow estimate and famous engine presets. 100% client-side.
Absolute Eosinophil Count (AEC) Calculator — Free Lab Tool
Free absolute eosinophil count (AEC) calculator: enter your total WBC count and eosinophil percentage to get AEC in x10^9/L and cells per microliter,
Equivalent Interest Rate Calculator — Convert Between Compounding Frequencies
Free equivalent interest rate calculator: convert nominal rates between compounding frequencies (monthly, quarterly, annual, continuous), nominal ↔ EAR, reverse solver, and a full conversion table.
ESLint Config (.eslintrc.js) Generator
Interactive .eslintrc.js config generator, JavaScript file linter, and rule builder supporting React, Node.js, and modern ECMAScript.
eV to MeV Converter | Electronvolt to Megaelectronvolt Calculator
Free ev to mev calculator: convert electronvolts (eV) to megaelectronvolts (MeV) and back. Also converts keV, GeV, joules, photon wavelength and frequency. 1 MeV = 1,000,000 eV.
EV/Sales Ratio Calculator — Enterprise Value to Sales
Free EV/Sales ratio calculator: compute the enterprise value multiple on annual sales, reverse solver (implied EV & implied revenue), 2-company comparator, plus FAQ. 100% client-side.
Feedline Lab — Coax Loss Calculator, dBm to Watts, S-Unit & ERP Suite
Free feedline lab: coax loss calculator for 13 cable types (LMR-400, RG-213, 9913, HELIAX…), cable chooser, dBm↔watts converter, S-unit converter, ERP/EIRP calculator and a printable coax loss chart. 100% client-side, no signup.
Feet to Yards Conversion: Convert ft to yd and yd to ft Calculator
Free feet to yards conversion calculator. Convert feet to yards (divide by 3) or yards to feet (multiply by 3), with a feet to yards chart, formula, football field and construction examples.
Filament Spool Planner — Weight↔Length↔Cost Converter & Will-It-Finish Check
Free filament spool planner: grams↔meters↔cost converter, will-this-spool-finish-my-print checker (weigh the spool → net filament → GO/NO-GO verdict), multi-spool inventory tracker, empty-spool weight database and a 1.75/2.85mm length reference. 100% client-side, no signup.
Fire Pit Size Calculator — 7 Ways to Size Your Fire Pit
Fire pit size calculator: 7 modes — guests, capacity, patio fit, brick ring, seating circle, propane BTU burn time, clearance check. Free, client-side
Firewood Stack Calculator - Cords, BTU, Weight & Seasoning Planner
Firewood stack calculator: stack to cords, face cords, species weight, BTU per cord, fuel cost vs propane and oil, log count, and seasoning planner.
Fishing Hook Size Lab — Actual-Size Chart, Converter & Species Guide (Free)
Free interactive fishing hook size lab: actual-size hook renderer (1:1 on screen + printable), aught/mm/inch/gap converter, species × bait recommendation matrix, hook style guide, tippet X chart, treble & circle hook charts. 100% client-side, no signup.
Fishing Line Calculator — Spool Capacity, Braid Backing, Diameter, IPT & Trolling Depth
Free fishing line calculator suite: reel line capacity (two methods), braid-to-mono backing planner, line diameter chart (mono/braid/fluoro), mm-to-lb test converter, reel gear ratio to inches-per-turn, fly leader builder, leadcore trolling depth, line counter calibration and spooling cost estimator. 100% client-side.
Fluid Ounces to Pounds Converter - fl oz to lb Calculator
Convert fluid ounces to pounds with this free fl oz to lb calculator. Pick water, milk, oil, honey, or enter a custom density. Includes conversion tables, the fl oz to lb formula, and answers to common questions.
Force Converter
Free force converter: convert newtons, pound-force, kilogram-force, dynes, kilonewtons, poundals, ounce-force and kips. Two-way live conversion, all-units table, batch mode, exact formulas. 100% client-side.
Fountain Pen Ink Capacity Calculator — Pages per Fill & Bottle Life (Free)
Free fountain pen ink capacity planner: filling-system database (cartridge, converter, piston, vacuum, eyedropper), pages-per-fill estimator, bottle-life calculator using Viseguy's Law, personal words-per-ml calibration, and 23 popular pens. 100% client-side.
Ft to M Converter: Feet to Meters and Meters to Feet
Free ft to m converter: convert feet to meters and meters to feet instantly. How many meters are in a foot? 1 ft = 0.3048 m exactly. Includes ft to meters chart, height, construction, and aviation examples.
Fuel Economy Converter: MPG to L/100km Calculator
Free fuel economy converter: convert MPG (US and UK) to L/100km and km/L, calculate trip fuel cost, and compare car fuel efficiency side by side.
Gallon to Tons Converter | Gallons to Tons Weight Calculator
Free gallon to tons calculator. Convert US and imperial gallons to metric tons, kilograms, US tons, long tons and pounds using liquid density (water, diesel, gasoline, oil, milk) or a custom kg/L value. Works both ways: tons to gallons too.
Gallon Converter: US and Imperial Gallons to Liters, Quarts, Pints, Cups, Ounces
Free gallon converter: convert gallons to liters, quarts, pints, cups and fluid ounces in US and imperial units. 1 US gallon = 3.78541178 liters, 1 imperial gallon = 4.54609 liters. Formula, quick table, and FAQ.
Gallons per Minute (GPM) Calculator
Gallons per minute calculator: bucket fill-time test, GPM converter (L/min, m3/h, GPH, CFS, L/s), fill-time planner, well drawdown and fixture tables.
Gematria Calculator: Hebrew, Jewish and English Gematria Values
Free gematria calculator: compute Hebrew (Mispar Hechrechi), Jewish, English, Simple/Ordinal and Reduced gematria values for any word or name. Side-by-side comparison, letter-by-letter breakdown and reference tables.
How Many Generations Ago Was That? — Generation Calculator
Free generation calculator: convert any year into generations ago with adjustable generation length (25/30/custom). Famous-event presets, ancestor count (2^n), ancestor age at any event, and a visual generation timeline. 100% private — runs in your browser.
Glitch Font Generator & Zalgo Horror Text Maker
Interactive glitch font generator, demonic text maker, broken text converter, and random word generator from letters.
Goat Gestation Calculator — Kidding Due Date, Timeline & Planner | nrtechstudio.com
Free goat gestation calculator: enter the breeding date to get an honest kidding due-date window (145–155 days), live countdown, milestone timeline, reverse breeding planner, multi-doe herd planner, kidding signs checklist and printable kidding kit list. 100% client-side.
Pakistan GPA Calculator (HEC) — Percentage to GPA, Semester GPA & CGPA
Free Pakistan GPA calculator using official HEC bands: percentage to GPA, semester GPA, CGPA, what-if planner, and Pakistan to US GPA converter. 100% client-side.
Gr to mL Converter: Grams to Milliliters Calculator
Free gr to ml converter: convert grams to milliliters and milliliters to grams for water, flour, sugar, butter, honey, oil, milk and lab chemicals. Verified density table, custom density, and a step-by-step breakdown of every calculation.
Grams to Teaspoons Converter (g to tsp) by Ingredient
Convert grams to teaspoons and teaspoons to grams for flour, sugar, salt, butter, honey, baking powder, baking soda and 6 more ingredients. Uses 1 US teaspoon = 4.92892159375 mL with verified densities.
CSS Gradient Generator Online
Free CSS gradient generator online. Color gradient generator, color gradient maker, gradient background maker, gradient background generator, gradient color creator, CSS linear gradient generator, CSS radial gradient generator, CSS text gradient generator, gradient maker online, gradient image generator, create gradient online, gradient editor, gradient bg generator, colour gradient generator, online gradient creator.
Gram to Liter Conversion Calculator
Free gram to liter calculator and liter to gram converter with a verified density table (water, milk, oil, honey, gasoline, diesel, ethanol, glycerin, flour), custom density, and US gallon and pint conversion. Shows every step of the calculation.
Grams to Calories Calculator: Protein, Carbs, Fat to Kcal (Atwater System)
Convert protein, carbs, fat, alcohol and fiber grams to kcal with verified Atwater factors. USDA food presets per 100 g, percentage breakdown. Free.
Grams to Fluid Ounces Converter - g to fl oz Calculator
Free grams to fl oz converter. Convert grams to fluid ounces (and fl oz to grams) for water, milk, oil, honey, sugar, flour, salt, or any custom density. US and Imperial fluid ounces supported, with show-your-work formula and conversion tables.
Grams to Kilograms Converter: g to kg Calculator with Formula
Free grams to kilograms converter and kilograms to grams converter. Convert g to kg (divide by 1000) or kg to g (multiply by 1000) with live results, show-your-work steps, quick conversion table, popular conversions, and FAQ.
Greek Gematria Calculator: Isopsephy Values for Greek Words
Free Greek gematria calculator (isopsephy). Type Greek text, with or without polytonic accents, and get the total numeric value plus a per-letter breakdown. Includes word comparison, a full Greek letter value chart, and verified classic examples such as Jesus = 888.
Grow Light Lab — PPFD, DLI & Hanging Distance Calculator
Free grow light photometry suite: hanging distance calculator (inverse-square law), lux/lumen/foot-candle to PPFD spectrum converter, PPFD↔DLI solver, LED wattage & coverage sizer, and growth-stage PPFD/DLI targets. 100% client-side.
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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.