Free Converters Tools & Calculators
Browse 349+ free interactive converters calculators, estimators, and utilities. 100% free, private, and runs directly in your browser without signup.
Kg to Newtons Converter — kg to N Calculator (Free, 2-Way) | nrtechstudio
Free kg to newtons calculator: convert kg to newtons and newtons to kg instantly. Supports N, kN, kgf, lbf, dyn, ozf, pdl, kip plus your weight on the Moon, Mars, and Jupiter. Formula F = m x g explained.
Kg to Stones Converter: Kilograms to Stones and Pounds
Convert kilograms to stones and pounds instantly: 70 kg = 11 st 0.3 lb. Two-way live converter with stones+pounds breakdown, precision control, show-your-work steps, and a quick reference table.
kJ to BTU Converter
Convert kilojoules to BTU and BTU to kilojoules instantly. Uses the exact IT convention: 1 BTU(IT) = 1055.05585262 J, so 1 kJ = 0.9478171203 BTU. Live two-way conversion, precision control, derivation steps, quick tables, HVAC context.
Knots to KPH Converter: Convert Knots to km/h Instantly (Free)
Free knots to kph converter. Convert knots to km/h instantly with an exact formula (1 knot = 1.852 km/h), multi-unit mode (mph, m/s, ft/s), conversion chart, Beaufort wind scale, and worked examples. 100% client-side.
Knots to MPH Converter: Knots to Miles per Hour Calculator
Free knots to mph calculator. Convert knots to miles per hour (and mph to knots) live, with multi-unit mode (knots, mph, km/h, m/s, ft/s), adjustable precision 0-10 decimals, show-your-work steps, a knots to mph chart, Beaufort scale, and boat and airplane speed context.
kPa to mmHg Conversion Calculator - Kilopascal to Millimeters of Mercury
Convert kPa to mmHg instantly with this free kilopascal to millimeters of mercury calculator. Live two-way conversion, mmHg to kPa, kPa to torr, conversion formula, chart, table, and blood pressure reference.
kPa to psi Converter: kilopascal to psi, Both Directions
Free live kpa to psi conversion tool: kilopascal to psi and psi to kPa, both directions. Exact factor 6.894757293168, swap, adjustable precision, quick kpa to psi chart, tire pressure examples, and 16 answered FAQs.
ksi to MPa Converter - Free ksi to MPa Calculator
Free ksi to MPa converter with live two-way conversion. Convert kilopounds per square inch (ksi) to megapascals (MPa), psi, kPa, GPa and Pa. Includes conversion factor, formula, quick chart, material strength tables and worked examples.
KSI to PSI Conversion Calculator
Free ksi to psi conversion calculator. Convert kilopounds per square inch to psi and back, plus MPa, kPa and Pa. Exact formula: 1 ksi = 1000 psi. Includes conversion chart, worked examples and FAQ.
kW to Joules Converter — Power × Time to Energy (J, kJ, kWh, BTU)
Convert kilowatts to joules with time: E(J) = 1000 × kW × seconds. Bidirectional kW↔J calculator, kJ/MJ/Wh/kWh/BTU/kcal outputs, practical presets, worked examples. Free, 100% client-side.
kW to kJ Converter — Kilowatts to Kilojoules Calculator (Free, No Sign-up)
Free kW to kJ converter: turn kilowatts × time into kilojoules. Reverse kJ → kW mode, power-rate converter (kJ/h, BTU/h, kcal/h, MJ/h), energy converter (MJ, kWh, BTU, kcal), worked examples & formulas. 100% client-side.
kW to kWh Calculator: Convert Kilowatts to Kilowatt-Hours
Free kW to kWh calculator: enter power in kW plus time to get energy in kWh (kWh = kW x hours). Reverse mode converts kWh to average kW, with electricity cost estimates and household appliance presets.
kW to MW Converter | Kilowatt to Megawatt Calculator
Convert kW to MW and MW to kW instantly. Live two-way kilowatt to megawatt converter with watts and gigawatts, formula, quick table, and worked examples. 1 MW = 1,000 kW exactly.
kW to Volts Calculator — DC, Single-Phase & 3-Phase Converter
Free kW to volts calculator: convert kilowatts to volts for DC, single-phase and three-phase (line-to-line / line-to-neutral) circuits with power factor. Also volts to kW, watts to volts mode, and a common-voltage current solver. 100% client-side.
kW to Wh Converter — Kilowatts to Watt-Hours Calculator | nrtechstudio.com
Convert kW to Wh with time: E(Wh) = P(kW) × 1000 × t(h). Free calculator with reverse mode, battery Wh from volts × amp-hours, UPS runtime sizing, worked examples, and honest limitations. 100% client-side.
Liters to Gallons Converter (US and Imperial)
Convert liters to gallons and back with this free l to gal calculator. 1 liter = 0.2642 US gallons or 0.2200 imperial gallons. Formula, quick liters to gallons chart, worked examples, and 16 FAQs.
Lat Long to UTM Converter | Zone, Easting, Northing Calculator
Free UTM coordinate converter: convert lat long to UTM zone, easting and northing (WGS84), reverse UTM to lat long, batch convert, and find your UTM zone on the map.
Lbs to Pounds Converter: Lbs to Kg, Ounces, Grams and Stones
Is lbs the same as pounds? Yes. Convert lbs to kg, pounds to kg, ounces, grams and stones with a two-way live converter, show-your-work steps, quick tables and the story of why pound is abbreviated lbs.
Lbs to PSI Calculator: Convert Force to Pressure (psi = lbs / in2)
Free lbs to psi calculator: turn force (lbs, N, kgf) and area (in2, cm2, mm2) into pressure in psi, kPa, bar and MPa. Includes reverse modes, quick table and worked examples.
Lbs to Stone Converter: Pounds to Stones Calculator
Convert lbs to stone instantly. Free pounds to stone calculator with stone and pounds breakdown, kg equivalent, conversion formula, quick chart, and worked examples. 1 stone = 14 lbs exactly.
Letter Grade to GPA Calculator
Convert any letter grade (A+ to F) to GPA on the 4.0, 4.3, or weighted 5.0 scale. Full conversion chart, batch averaging, and worked examples.
Light Year Conversion Calculator: ly to km, Miles, AU and Parsec
Convert light years to km, miles, metres, AU, and parsecs with this live light year calculator. 1 light year = 9,460,730,472,580.8 km exactly. Two-way converter, quick table, and worked examples.
Lighting Unit Converter -- Lumens, Lux, Foot-Candles, Candela, Nits | nrtechstudio
Free lighting and photometry converter: lumens, lux, foot-candles, candela, nits, lumens/watt. Plus watts-to-lumens by bulb type, room lighting planner, inverse-square-law and beam-angle calculators. 100% client-side.
Linear Feet to Square Feet Calculator
Convert linear feet to square feet: enter length in linear feet and width to get square footage, waste allowance, tile/plank/carpet/sod estimates, and a reverse linear-feet mode. Free, no signup.
Link Into HTML – Anchor Link, Button Hyperlink & URL Encoder
Link into html, html button link, ascii encoding, anchor link html, html button hyperlink, href hyperlink, hyperlink code, href code, python encode url, valid url characters, href syntax, link tag example, url encoding chart, link element html, js html decode, url encode 20, html to url, url tag, html to url converter, special characters must be escaped html, a href coding, data urlencode, syntax for url, html code for hyperlink button, a href format, html href style, html escape characters online, href to anchor, html anchor in page, make a url link.
List To Json
Convert a text list into a JSON string array.
Liter to cc Converter - Convert Liters to cc and cc to Liters
Free liter to cc converter: convert liters to cc (cubic centimeters) and cc to liters with exact factors, plus mL, cubic inches and US fluid ounces. 1 liter = 1,000 cc exactly.
Liters to Moles Calculator: Convert Gas Volume to Moles at STP
Free liters to moles calculator: convert gas volume to moles at STP (22.414 L/mol) or with custom pressure and temperature via PV=nRT, plus liquid mode using density and molar mass. Formulas, tables, and worked examples.
Liters to Pounds Converter - L to lb Calculator
Convert liters to pounds with this free L to lb calculator. Pick from 14 liquid densities or enter a custom density. Includes conversion tables, the liters to pounds formula, worked examples, and answers to common questions.
Lumens to Lux Calculator — Convert Lumens to Lux (with Area) | nrtechstudio
Free lumens to lux calculator: E(lux) = lumens / area(m²). Also lux to lumens, foot-candle mode, room planner with recommended lux per room, formulas, charts and worked examples. 100% client-side.
MAC Address Converter & Formatter
Standalone professional MAC address converter, formatter, and identifier. Convert between colons, hyphens, Cisco dots, raw hex, and inspect OUI vendors and EUI-64 addresses.
Make Text Upside Down – Reverse String & Text Transformer
Make text upside down, alphabetical order creator, reverse alphabet, help in morse, speech reverse, morse translator audio, binary code creator, create upside down text, how to invert words in word, reverse the sentence, upside down and backwards text, sentence reverser, upside down text gen, reverse alphabetical order, reverse string online, write backwards text, numbers to words code translator, reverse writer, written in reverse, font backwards generator, reverse characters, alphabet reversed, reverse alphabet translator, reverse alphabet decoder, backward word translator.
Markdown Formatter, Editor & Converter
Free web markdown editor, formatter, and visualizer. Convert markdown to HTML online, markdown to text, text to markdown, and print to PDF.
MB to GB Converter - Convert Megabytes to Gigabytes (Decimal and Binary)
Convert MB to GB and GB to MB instantly. Honest decimal (SI: 1 GB = 1000 MB) and binary (IEC: 1 GiB = 1024 MiB) modes, live KB MB GB TB PB panel, precision control, and real-world file size context.
MCG to MG Converter: mcg, mg, g, kg Mass Units
Free mcg to mg converter (1 mg = 1000 mcg exact). Convert both directions between mcg, mg, g and kg with adjustable precision, step-by-step working, a quick label table and 15 FAQs.
mcg to mL Calculator: Dose, Concentration, and Volume
Free mcg to mL calculator with 3 modes: dose plus concentration to volume, volume plus concentration to dose, dose plus volume to concentration. Educational concentration math with unit selectors (mcg/mg/g, mcg/mL/mg/mL/g/L, mL/L).
Markdown to Image Tag & HTML Converter
Standalone professional Markdown to HTML image converter and markdown img tag generator. Convert markdown image syntax to HTML with responsive options, lazy loading, and live preview.
Mean Sac Diameter Calculator — MSD to Gestational Age & Discriminatory Zone | nrtechstudio.com
Free mean sac diameter (MSD) calculator: average 3 gestational-sac ultrasound dimensions, estimate gestational age (MSD + 30 rule), and check the 25 m
Mesh to Micron Converter (ASTM E11 and Tyler)
Convert sieve mesh number to micron opening and back. Lookup tables for ASTM E11 and Tyler standard sieve series, reverse micron to mesh finder, and full conversion charts.
Mg to Tablespoon Converter
Convert mg to tablespoons and tablespoons to mg with real cooking-ingredient densities. Free mg to tablespoon calculator with show-your-work steps.
Micron to Mil Converter: µm to thou (mil) and back
Convert microns (µm) to mils (thou) and mils back to microns with exact math: 1 mil = 25.4 microns. Live converter, mm/inch panel, quick tables, paint, PCB copper and plastic film thickness references.
Mile Conversion Hub: Miles to KM, Feet, Meters, Yards, Nautical Miles
Convert miles to kilometers, feet, meters, yards, and nautical miles, two ways per pair. Exact definitions: 1 mi = 1609.344 m, 1 nmi = 1852 m.
Mirror Text Generator & Upside Down Flip Tool
Interactive mirror text generator, upside down flip text converter, and backwards letter reverser for social media.
mL to Cups Converter: mL to US, Metric and Imperial Cups
Convert milliliters to US cups, metric cups and imperial cups. Exact definitions: 1 US cup = 236.5882365 mL, 1 metric cup = 250 mL, 1 imperial cup = 284.130625 mL. With tablespoons, teaspoons, fl oz, show-your-work and quick table.
mL to µL Converter: Milliliters to Microliters
Free mL to µL converter: convert milliliters to microliters and back (1 mL = 1,000 µL exactly), plus liter, cc and drop conversions, worked examples and lab reference tables.
Moisture Content Calculator — Dry Basis vs Wet Basis, Oven-Dry Method
Free moisture content calculator: compute dry-basis and wet-basis moisture from wet and dry sample weights (g, kg, lb), convert between bases, solve t
Morse Code to Hex & English Translator
International Morse code converter, audio synthesizer, hex translator, and real-time audio-to-text decoder.
Mushroom Yield Estimator — Flush-by-Flush Harvest Projection by Species & Substrate
Free mushroom yield calculator with a 12-species biological efficiency (BE) dataset: project flush-by-flush harvests (flush 1/2/3 with diminishing returns) from substrate weight, convert fresh to dried weight, and estimate batch cost, revenue and break-even. 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.