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.
What Size TV Should I Get? TV Size & Viewing Distance Calculator (THX, SMPTE, 4K)
Free TV size & viewing distance calculator. Bidirectional solver: enter seating distance to get the ideal TV size, or enter your TV size to get the ideal distance range. THX 36°, SMPTE 30°, and 4K visual-acuity modes, plus TV mounting height and wall-fit checks. 100% client-side.
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.
Tweet Length Checker — Twitter/X Character Counter (Weighted Rules)
Free tweet length checker using X's real weighted rules: URLs count as 23, emoji as 2, CJK double. Live 280-char bar, thread splitter, 100% client-side.
Twist Rate Calculator — Greenhill Formula, Miller Stability Factor & Bullet RPM
Free twist rate calculator: Greenhill formula (T=150·D²/L or 180·D²/L), Miller stability factor Sg, bullet RPM from muzzle velocity, caliber presets (.223, .308, 6.5 CM) and recommended twist tables per caliber.
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.
Txt To Html Converter
Txt To Json
Text to Leet Speak — Convert Text to 1337 Online
Convert text to leet speak (1337) online. Three intensity levels - mild, full, ultra - with per-letter toggles and uppercase preserved. 100% client-side.
Timezone Offset Calculator — Hour Difference Between Zones
Free timezone offset calculator: hour difference between any two IANA timezones on any date, with DST handled automatically. 100% client-side.
UK Take-Home Pay Calculator 2026/27
UK take-home pay calculator for 2026/27 — gross salary to net pay after Income Tax (20/40/45%) and National Insurance (8/2%), reverse solver, comparison and marginal-rate breakdown. 100% client-side.
ULID Generator — Generate Universally Unique Lexicographically Sortable Identifiers Online Free
Free online ULID generator: create sortable unique IDs in your browser. Bulk generate, decode ULID timestamps, validate format — no signup, client-side.
Uncooked to Cooked Rice Calculator — Rice Yield, Water Ratio & Servings
Free uncooked to cooked rice calculator: convert uncooked rice to cooked yield for white, basmati, jasmine, brown & wild rice. Get water needed, servings per person, and reverse cooked-to-uncooked conversion.
Unicode Lookup — Find Character Code, Name & HTML Entity
Free online Unicode lookup: look up any character by typing it or its code point (U+1F600, decimal, HTML entity) and get its official name, UTF-8/UTF-16 encodings, HTML/CSS/Python escapes, block, category, and script. 100% client-side.
Unicode Text Converter
Unisex Name Generator – Randomiser Wheel & Giveaway Picker
Unisex name generator, randomiser name wheel, random order generator names, random chooser generator, name generator for drawing, ancient name generator, random name generator in excel, random name selection, random circle generator, random names spinner, wizard name generator based on your name, giveaway name generator, app for random name drawing.
Unit Converter Table & Measurement Engine
Multi-category unit converter, unit converter length, metric conversion line, volume metric conversion, and linear mass density solver.
Unit Converter & Meter to Miles Calculator
High-performance unit converter, meter to miles calculator, weights and measures conversion, metric to imperial calculator, and conversion charts.
United States Telephone Number Format – Phone Formatter & Validator
United states telephone number format, american format phone number, united states phone number format, phone number format usa, overseas phone number format, format for us phone number, foreign phone number format, phone format, format international phone number country code, valid telephone number format, how to format international phone numbers, united states cell phone number format, phone number format with extension, north american phone number format, ext phone number format, us phone number format example, phone number with area code format.
Unix Timestamp Converter — Epoch to Date & Back
Free Unix timestamp converter: epoch to date and date to epoch with live ticking clock, auto-detect seconds/ms/us/ns, ISO 8601, RFC 2822, timezone picker and batch mode. 100% client-side.
Unslugify Text — Convert URL Slugs to Readable Text
Free unslugify tool: turn URL slugs back into readable text with title/sentence case, date-prefix and trailing-ID stripping, full-URL extraction, and batch mode. 100% client-side.
Upholstery Fabric Calculator — How Much Fabric for Sofa, Chair, Ottoman Headboard
Free upholstery fabric calculator: estimate yardage for sofas (14–18 yd), armchairs (5–7 yd), ottomans, dining chairs, and headboards. Custom panel mode, cushion math, pattern-repeat and tufting add-ons. 100% client-side.
Urine Anion Gap (UAG) Calculator — NAGMA Interpretation & NH4+ Estimation
Urine anion gap calculator (UAG = (U_Na + U_K) − U_Cl): normal anion gap metabolic acidosis interpretation, urinary ammonium excretion estimation, NAGMA decision tree, RTA differential table, and primary-literature-based FAQ.
Urine Output Calculator — mL/kg/hr Rate + KDIGO AKI Criteria
Free urine output calculator: compute mL/kg/hr rate, convert mL/hr and mL/24 hr, check oliguria/anuria criteria and KDIGO 2012 AKI staging, plus hourly serial monitoring. 100% client-side, educational — not medical advice.
Advanced URL Encoder & Decoder with Character Selection
Standalone custom url encode decode tool and online url percent encoding tool. Encode url characters tool, examine url encoding codes, url percent encoding, and what is urlencode with zero AI slop.
URL Encoder/Decoder
Free URL encoder and decoder: percent-encode query parameters or full URLs with encodeURIComponent vs encodeURI explained, double-encoding detection, live mode, and a per-character encoding breakdown.
URL Param Decoder (Standalone)
Decode URL query parameters: raw vs decoded table, double-encoding layers, duplicate keys, encoding-type detection, UTM flags. 100% client-side.
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.
URL Parser & Analyzer Online
Free online URL parser, URL scanner, and URL analyzer. Parse URL components tool, online URL path analyzer, and parse URLs from string online for developers.
URL Slug Generator — SEO-Friendly Slugs
Free URL slug generator: turn titles into clean, SEO-friendly slugs with stop-word removal, max-length cap, prefix/suffix, bulk mode, and live URL preview. 100% client-side.
URL Summarizer & Text Shortener Tool
Interactive URL summarizer, extractive text shortener, paragraph reducer, and online find-and-replace text tool.
URL to MD Link — Free Markdown Link Generator
Free URL to Markdown link generator: wrap any URL in [text](url) syntax with auto-title, Markdown escaping, reference-style and image modes. 100% client-side.
URL Checker & Link Syntax Validator
High-precision online URL checker, link syntax validator, regex URL validation tester, and RFC 3986 URI inspector.
URR (Urea Reduction Ratio) Calculator + Kt/V Estimate — nrtechstudio.com
Calculate Urea Reduction Ratio (URR) from pre- and post-hemodialysis BUN, KDOQI ≥65% target interpretation, spKt/V estimate, and the Daugirdas formula. Free, 100% client-side.
User Agent Parser Online (Free) — Parse UA Strings, Bulk Analyzer & Bot Detector
Free online user agent parser: paste any UA string to identify browser, OS, device, engine and bots. Bulk user agent parser for log analysis with CSV export. 100% client-side — your data never leaves the browser.
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.
UTF-8 Encoder Online — Text to UTF-8 Bytes
Free UTF-8 encoder online. Convert text to UTF-8 bytes in hex, decimal, or binary with a per-character table of code points and byte sequences. 100% client-side.
Advanced UTM Builder (Standalone)
Advanced UTM tracking link builder for campaigns: live validation, one-click presets, bulk mode, session history. 100% client-side.
UTM Parameter Parser (Standalone)
Extract UTM tracking tags from URLs, detect click IDs, validate tags, batch-parse links, and build campaign URLs. 100% client-side.
UUID Generator — Generate v1, v3, v4, v5, v7 UUIDs Online Free (Bulk + Validator)
Free online UUID generator: create v1, v3, v4, v5 and v7 (RFC 9562) UUIDs in your browser. Bulk generate up to 10,000, validate any UUID, decode v1/v7 timestamps. No signup, 100% client-side.
VA Disability Calculator 2026 — Combined Ratings, Bilateral Factor & Pay
Free 2026 VA disability calculator: combined ratings (38 CFR 4.25), bilateral factor (38 CFR 4.26), what-if claim planner, and 2026 monthly pay tables. 100% client-side.
VA Loan Calculator — Payment, Funding Fee & Affordability
Free VA loan calculator: monthly payment with the VA funding fee (first vs subsequent use), VA vs conventional (PMI) comparison, and VA loan affordability estimator. 100% client-side.
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.
Vaccine Efficacy Calculator (VE) — 2×2 Table + Confidence Interval
Compute vaccine efficacy (VE) from a 2×2 table: attack rate, relative risk, 95% confidence interval (Katz method), ARR, NNV, and statistical tests. Free, 100% runs in your browser.
Java JSON Schema Validator Generator
Interactive Java JSON Schema validator code generator and online schema tester for NetworkNT, Everit, and Jackson.
Valve Flow Coefficient Calculator — Cv & Kv, Liquid & Gas Sizing
Free valve flow coefficient calculator: find Cv from flow & pressure drop, solve for flow or pressure drop, size gas valves with critical-flow check,
Van Build Cost Calculator — Campervan Conversion Cost Estimator (Free)
Free van build cost calculator: line-item campervan conversion cost estimator with 14 categories (electrical, solar, insulation, plumbing...), base-van presets (Transit, Sprinter, ProMaster, Ducato), DIY vs pro labor, timeline planner and running costs. USD, GBP, EUR, AUD, CAD. 100% client-side.
Van der Waals Equation Calculator — Real Gas P, V, n, T Solver
Solve the van der Waals equation of state: compute pressure, volume (cubic solver), moles, or temperature for real gases. Built-in a/b constants for 8
Van Life Budget Calculator — Monthly Cost: Boondocking vs Campgrounds, Solo/Couple/Family, US/EU/UK/AU
Free van life budget calculator: style-based monthly budgeting with a boondocking slider, solo/couple/family modes, US/EU/UK/AU region presets, cost per mile vs cost per night, emergency fund planner, and a van-life-vs-rent comparator. 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.