Free Online Tools for Everything You Do
Browse 2,706+ free interactive tools - home improvement estimators, pet calculators, cooking converters, automotive tools, finance planners, fitness calculators, developer utilities and more. No sign-up. 100% private. Runs entirely in your browser.
MELD Score Calculator — MELD & MELD-Na with 3-Month Mortality Estimate
Free MELD calculator: compute MELD and MELD-Na scores from bilirubin, INR, creatinine and sodium (Kamath et al. formula + UNOS/OPTN rules). Unit conversion, dialysis toggle, clamp/cap handling, worked breakdown and published 3-month mortality bands. Educational estimate only — not medical advice.
Mentzer Index Calculator — MCV/RBC Ratio for Thalassemia vs Iron Deficiency | nrtechstudio
Free Mentzer index calculator: MCV divided by RBC count with cutoff 13 (Mentzer, Lancet 1973) plus RDW and RBC-count supporting features to suggest th
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.
Meta Tag Analyzer
Free online meta tag analyzer — paste HTML to audit title, meta description, Open Graph, Twitter Cards, canonical, robots, hreflang and more with a 0-100 SEO score, SERP previews and fix recommendations. 100% client-side.
Meta Desc Len
Check SEO meta description character & pixel width.
Metacam Dosage Calculator for Cats — Meloxicam 0.5 mg/mL Dose by Weight (Day 1 vs Maintenance)
Estimate Metacam (meloxicam) 0.5 mg/mL oral dose for cats by weight per the label: day-1 0.1–0.2 mg/kg, then 0.05 mg/kg once daily — in mL, mg, and drops, plus contraindication checklist. Educational
Meteor Shower Night Planner — What's Active Tonight, Peak Countdown & Best Viewing Hours
Free interactive meteor shower planner: check which meteor showers are active tonight, live countdown to peak, moon-interference score, tonight rating, and the best hours to watch — all computed in your browser.
MEWS Score Calculator — Modified Early Warning Score (Subbe 2001)
Free MEWS calculator: Modified Early Warning Score from 5 vital signs (Subbe et al., QJM 2001). Risk bands, escalation guidance, and a serial trend tr
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.
Microscope Calculator Lab — Total Magnification, FOV, Resolution & More
Free microscope calculator lab: total magnification, field of view from field number, cell size estimator, Abbe resolution limit, empty-magnification checker, stage micrometer calibration, and stereo vs compound chooser. 100% client-side.
Microwave Wattage Converter | Convert Cooking Time Between Wattages
Free microwave wattage converter: convert cooking time between any microwave wattages (600W–1250W). Instant two-way conversion with the linear formula time₂ = time₁ × (W₁ / W₂), quick conversion table, and honest limits.
Middle School GPA Calculator (No Credits Needed)
Free middle school GPA calculator. Enter letter grades for each class to get your GPA on the 4.0 scale. No credit hours needed, plus/minus toggle, core vs elective weighting, semester average.
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.
Mileage Reimbursement Calculator — IRS Rates 2026, 2025, 2024 (Free)
Free mileage reimbursement calculator with official IRS standard mileage rates for 2026 (72.5¢/mi), 2025 (70¢/mi), 2024 (67¢/mi). Business mileage calculator, year-over-year rate comparison, mileage log with CSV export, and standard mileage vs actual expense comparison. 100% client-side, no sign-up.
Miles to Kilometers Converter
Real-time miles to kilometers converter, kilometer conversion suite, meter to kilometer calculator, race paces, and conversion tables.
Miles to Steps Calculator — Convert Miles, Km and Steps (Height-Based Estimate)
Free miles to steps calculator and converter. Enter miles or km (plus optional height) to estimate steps, or convert steps back to miles and km. Walking stride model, no sign-up.
MIME Type Lookup
Free MIME type lookup: enter a file extension to get its MIME type, or reverse-search a MIME type to find matching extensions. 354 types, one-click copy, 100% client-side.
Minecraft Stack Calculator — Items to Stacks, Shulker Boxes & Chests
Free Minecraft stack calculator: convert items to stacks (64, 16, or 1 per stack), plan shulker boxes (27 slots = 1,728 items) and double chests (54 slots = 3,456 items). Includes item stack-size presets.
Minimum Common Multiple Calculator – LCM & GCF Finder
Minimum common multiple calculator, find the greatest common multiple, how to find the greatest common factor of two numbers, how to find greatest common multiple of two numbers, find the common factor calculator, highest common denominator calculator, biggest common denominator calculator, how to find gcf on calculator, how to figure out greatest common factor, how to find the greatest common divisor of two numbers, lcm multiple calculator, largest common denominator calculator, least common factor finder, lcm and gcf finder, gcf of polynomials calculator, lcm calculator for fractions, how to find the gcf of 2 numbers, how to find the greatest common factor in math, greatest common factor of two monomials calculator, common factor algebra calculator, highest common factor calculator online, how to calculate greatest common factor, online gcd calculator, greatest common factor of two numbers, find lcm calculator, fraction gcf calculator, greatest factor calculator, how to calculate gcf of 2 numbers, common factor calculator fractions, greatest common divisor finder.
Minutes From Now Calculator - Add or Subtract Minutes From Any Time
Free minutes-from-now calculator: add or subtract minutes or hours from any clock time (or right now) and get the exact result time with day-rollover indicator. 12h/24h toggle, duration-between-times mode, worked examples.
Mirror Equation Calculator — Solve f, do, di, M
4-way mirror equation calculator: compute focal length (f), object distance (do), image distance (di), or object height (ho). Automatic image classification (real/virtual, upright/inverted, magnified/reduced) + SVG ray diagram.
Mirror Size Calculator — Find the Right Mirror Size for Every Wall
Mirror size calculator: right width and hanging height for console, vanity, mantel, sofa, dresser, and leaning mirrors — imperial + metric.
Mirror Text Generator & Upside Down Flip Tool
Interactive mirror text generator, upside down flip text converter, and backwards letter reverser for social media.
Miter Angle Calculator — Compound, Polygon & Segmented Turning
Free miter angle calculator: simple corner miters, polygon/frame miters (180/N), compound miter + bevel for crown molding (spring angle), and a segmented-turning mode for woodturners. Metric/imperial, live SVG diagrams, printable charts. 100% client-side, no signup.
Mixed Air Temperature Calculator — HVAC Mixer, Reverse OA Solver & OA% Table
Free mixed air temperature calculator for HVAC: blend 2–4 air streams by CFM (weighted average), reverse-solve outside-air CFM from a target mixed air temperature, and build an outside-air % vs mixed air temp table. Presets for AHU economizer, rooftop units & classrooms. °C / °F / K. 100% private —
Mixed Air Calculator — Psychrometric Mixer: Temperature, Humidity, Enthalpy
Free mixed air calculator: mix two airstreams (outside air + return air) and get the full psychrometric result — mixed air temperature, relative humidity, humidity ratio, enthalpy, dew point and wet bulb. AHU/economizer mode, CFM or m³/min, °C/°F, 100% in-browser.
Air Mixing Ratio Calculator — w = 0.622·e/(p−e)
Free air mixing ratio calculator: compute the water-vapor mixing ratio (g/kg) from temperature & RH via Tetens or from vapor pressure directly, plus specific humidity q = w/(1+w) and the inverse w → e mode. 100% client-side.
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.
MLVSS Calculator — F/M Ratio, MCRT & SVI
Free MLVSS calculator: mixed liquor volatile suspended solids from MLSS, F/M ratio, MCRT sludge age, and SVI settleability. US and metric units.
mmol/L to mg/dL Converter — Glucose, BUN & Creatinine
Free mmol/L to mg/dL converter for blood sugar (glucose ×18.0182), BUN/urea (×0.357) and creatinine (×88.4 µmol/L). Two-way conversion with transparent factors, molecular weights, reference ranges and worked examples.
MOA Calculator — Minute of Angle: Scope Clicks, MOA to Inches & MOA to MRAD
Free MOA (Minute of Angle) calculator for sport optics: convert impact offsets to MOA corrections and scope turret clicks, convert MOA to inches or cm at any distance, convert MOA to MRAD, estimate range with an MOA reticle, and use the MOA subtension table. 100% client-side, no data leaves your bro
MIRR Calculator (Modified IRR): Compute Modified Internal Rate of Return
Free MIRR calculator: compute Modified Internal Rate of Return from cash flows with separate finance & reinvestment rates, compare IRR vs MIRR, rank 2 projects, and solve for the reinvestment rate.
Modular Scale Calculator — Typography Scale Generator
Free modular scale calculator: build harmonious typography scales from any base size and ratio, with live preview and CSS variable export. 100% client-side.
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
Molar Ratio Calculator — Mole Ratios, Limiting Reactant & Theoretical Yield
Free molar ratio calculator: mole-to-mole ratios from any balanced equation, mass-to-mass stoichiometry, limiting reactant finder and theoretical yield with step-by-step solutions. 100% client-side, no signup.
Cashier Change Calculator — Compute Change + Rupiah Denomination Breakdown
Compute cashier change: purchase total and cash paid become change plus an optimal rupiah denomination breakdown. Includes a limited cashier-stock mode, a two-payment comparator, and a wallet solver. Free, 100% in-browser.
Money Counter: Count Total Rupiah Stack + Denomination Breakdown
Count the total value of a rupiah cash stack: enter the count of each denomination to get the total plus per-denomination breakdown. Includes a target-check mode, two-stack comparator, and denomination combinations. Free, 100% in-browser.
Money Market Account (MMA) Calculator — Tiered Interest, Break-Even & Projection
Money market account calculator: compute tiered interest rates, compare MMA vs savings vs CDs, find the break-even balance for monthly fees, and project 12 months with regular deposits.
Money Multiplier Calculator
Macroeconomics money multiplier calculator: simple model m = 1/rr, full model m = (1+c)/(rr+e+c), policy-scenario comparator, and solver. 100% runs in your browser.
Money Supply Calculator (M0/M1/M2) — Money in Circulation
Compute monetary aggregates M0, M1, and M2 from their components (currency, demand deposits, savings, time deposits), compare two periods, compute from monetary base × money multiplier, or find the component needed for an M2 target.
Money Weight Calculator — How Much Does Cash Weigh?
Free money weight calculator: enter bills and coins by denomination to get total weight and face value. USD, EUR, GBP. Bulk estimator: how much does $1 million weigh?
Monitor Dimensions Calculator – Display Ratio & Aspect Ratio
Display ratio calculator, calculate aspect ratio, monitor dimensions calculator, ratio proportion calculator, inch to pixel calculator, pixel ratio converter, px ratio calculator, px convert to cm, image ratio finder, aspect ratio calculator inches, 3 4 aspect ratio calculator, pts to px converter, resolution calculator ratio, screen resolution calculator, pic size calculator, mm to pixels calculator, image aspect ratio finder, conversion pixel cm, calculate pixel aspect ratio, how to calculate resolution of an image, pixel cm calculator, aspect ratio calculator online, convert inch to px, pixels calculator, ratio size calculator, display aspect ratio calculator, get image ratio, online inches to pixels converter, aspect ratio visualizer, square dimensions calculator.
Month-over-Month (MoM) Calculator: Monthly Growth & Annualization
Calculate month-over-month (MoM) growth: % change vs last month, monthly series with average MoM, annualization (1+m)^12-1, target value solver, and two-series comparator. Free, 100% in your browser.
Monthly Income Calculator — Gross & After-Tax Monthly Income from Any Pay Frequency
Free monthly income calculator: combine multiple income streams (hourly, weekly, biweekly, monthly, annual), estimate after-tax monthly take-home pay, and break it into a 50/30/20 monthly budget.
Tool - Monthly Payment Calculator Mortgage Taxes and Insurance
Universal monthly payment calculator for mortgage, taxes, and insurance (PITI), complete with amortization schedule, personal loan calculator, and principal and interest breakdown.
Moon Phase Calculator — Birthday Moon, Couple Match & Lunar Calendar
Free moon phase calculator for any date: illumination %, moon age, moonrise/moonset, your birthday moon, couple moon-phase match (just for fun), lunar calendar and moon wallpaper. 100% client-side, 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.