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.
Batting Strike Rate Calculator — Cricket SR, Runs Needed & Balls Allowed
Free cricket batting strike rate calculator. Compute strike rate from runs and balls faced, work out runs needed for a target strike rate, or balls allowed at a target rate — with format context (Test, ODI, T20).
BBCode to HTML Converter
Free online BBCode to HTML converter — paste forum BBCode from phpBB, vBulletin, XenForo or MyBB and get clean, XSS-safe HTML with live preview. 100% client-side.
BBCode to Markdown Converter
Free BBCode to Markdown converter — convert forum BBCode back to Markdown online with live preview. Bold, lists, quotes, code, tables, links and images for phpBB, vBulletin, MyBB, XenForo and SMF. 100% client-side.
BC to AD Converter — BCE/CE & Astronomical Year Converter | nrtechstudio
Free two-way BC/BCE to AD/CE year converter. Convert any year between historical and astronomical numbering (no year zero handled honestly) and compute elapsed years between two dates across eras. 100% client-side.
Bcrypt Password Generator & Hash Studio
Interactive bcrypt hash generator, bcrypt password generator, bcrypt password hash verifier, and authentication tool.
Bcrypt Validator & Hash Inspector
Real-time Bcrypt hash syntax validator, cost factor analyzer, and modular crypt format diagnostic tool.
Beam Load Calculator — Reactions, Shear, Moment & Deflection
Free simply-supported beam load calculator: support reactions, shear force & bending moment diagrams, and deflection estimates for point, uniform, and triangular loads. Metric + imperial, wood & steel presets.
Beat Frequency Calculator — f_beat = |f₁ − f₂| + Missing-Frequency Solver
Free beat frequency calculator: compute f_beat = |f1 − f2|, beat period T = 1/f_beat, solve the unknown tone (f2 = f1 ± f_beat), with Hz/kHz/BPM units and tuning examples.
Bee Syrup Calculator — Sugar Water Ratios, Batch Mixer & Feeding Planner
Free bee syrup calculator: 1:1 and 2:1 sugar syrup recipes for bees by weight, batch mixer (sugar + water for any volume), fondant & invert modes, hive feeding planner with seasonal schedules, feeder refills, and sugar cost estimator. 100% client-side.
Beer ABV Calculator — OG/FG, Refractometer Correction, Hydrometer Temp Correction (Free)
Free beer ABV calculator lab: standard, alternate & real-extract formulas side-by-side, refractometer alcohol correction (Terrill), hydrometer temperature correction, attenuation, dilution, Brix/Plato/SG converter. 100% client-side.
Beighton Score Calculator — 9-Point Joint Hypermobility Test
Free Beighton score calculator: the 9-point joint hypermobility screening test (5 maneuvers, bilateral scoring). Age-adjusted cutoffs (2017): ≥6 pre-p
Belt Size Calculator — Find Your Belt Size in Inches, CM & S/M/L
Free belt size calculator: belt size from waist or pants size, inches to cm converter, men's, women's and kids' belt size charts, and a guide on how to measure belt size.
Benadryl Dosage Calculator for Dogs — Diphenhydramine mg by Weight + Tablet Guide
Estimate Benadryl (diphenhydramine) dosage for dogs by weight: 1 mg per pound every 8-12 hours, converted to 25 mg tablets and liquid mL. Educational estimate, not veterinary advice.
Bench Press Calculator — 1RM Max, Plate Loader & Strength Ratio
Free bench press calculator: estimate your 1RM max from weight × reps with 4 formulas (Epley, Brzycki, Lombardi, O'Conner), % of 1RM training table, plate loader per side, and bodyweight strength ratio.
Bench Press Pyramid Calculator — 1RM Pyramid Workout Generator
Generate a bench press pyramid workout from your 1RM. Ascending, descending and full pyramid tables with %1RM x reps, set volume, total volume and rest times.
Bench Size Calculator — Dining, Entryway & Bedroom Bench Dimensions
Bench size calculator — find the right dining, entryway & bedroom bench length, seat height and depth from your table, wall or bed size. 7 sizing
Bencode Decoder — Decode BitTorrent Bencode to JSON Online
Free online bencode decoder: decode BitTorrent bencode strings to JSON with strict validation, tree view, and UTF-8/hex/base64 output.
Bencode Encoder — JSON to BitTorrent Bencode Online
Free online bencode encoder: convert JSON to BitTorrent bencode format with live encoding, tree view, and hex dump.
Sheet Metal Bend Calculator — Bend Allowance, Tonnage, V-Die & Flat Pattern (Free)
Free sheet metal bending suite: bend allowance & deduction calculator, multi-bend flat pattern, K-factor lookup, press brake tonnage (air/bottoming/coining), V-die selector and punching force. Metric + imperial. 100% private, runs in your browser.
Benzo[a]pyrene Exposure Calculator — Estimate Daily B[a]P Intake (Free, Online)
Free online benzo(a)pyrene exposure calculator. Estimate your daily benzo[a]pyrene (B[a]P) intake in ng/day from grilled food, cigarettes, city air and wood stoves — with literature ranges, EU reference comparison and cigarette equivalents. Educational estimate only.
Berg Balance Test Calculator — 14-Item Score 0–56 & Fall-Risk Category | nrtechstudio.com
Free Berg Balance Scale calculator: score all 14 balance items (0–4 each, total 0–56), get the fall-risk category with per-item instructions, and copy
Bernoulli Equation Calculator — Solve P, v, z, Venturi & Head Terms
Free Bernoulli equation calculator: solve for the missing variable (P1, v1, z1, P2, v2, z2) in P/rho*g + v^2/2g + z with full head-term breakdown, venturi meter mode, manometer input, and unit convers
Best Software Development Company & Project Estimator
Interactive project cost estimator, enterprise custom software engineering architecture, and bespoke software agency guide.
Bi-Weekly Mortgage Payment Calculator — Interest Saved & Payoff Time
Free bi-weekly mortgage payment calculator: pay half your monthly payment every two weeks, compare vs monthly payments, see interest saved, payoff acceleration, and model extra payments. 100% client-side, no data leaves your device.
Bicarbonate Deficit Calculator — Metabolic Acidosis HCO3⁻ Correction Estimate
Free bicarbonate deficit calculator: (target − measured) × weight × distribution factor, half-dose estimate, mL of 8.4%/7.5%/4.2% NaHCO3 and infusion
Bike Cadence & Speed Calculator — Cadence ↔ Speed via Gears
Convert bike cadence (rpm) to speed (km/h, mph) or find the cadence you need for a target speed, using chainring, cassette cog and wheel size.
Bike EMI Calculator — Two-Wheeler Loan EMI with Down Payment
Free bike EMI calculator for two-wheeler loans in India. Enter on-road price, down payment, interest rate (reducing balance) and tenure to get monthly EMI, total interest, and a full amortization schedule. 100% client-side, no sign-up.
Bike Frame Size Calculator — 7 Sizing Modes
Free 7-mode bike frame size calculator: road, MTB, hybrid and gravel sizing from inseam, LeMond saddle height, reach and stack, standover check, kids bike sizer, size converter.
Bike Gear Calculator — Gear Inches, Development & Gain Ratio
Free bike gear ratio calculator: enter chainring, cog and wheel size to get gear inches, development, gain ratio and a speed-at-cadence table. Modern take on the classic gear calculator.
Bike Speed Calculator — Speed ↔ Pace ↔ Time (Free)
Free bike speed calculator: convert speed to pace (2:00/km style), pace to speed, average speed from distance & time, and ride-time estimates. km/h & mph, min/km & min/mi. 100% client-side.
Bill Rate Calculator — Staffing Bill Rate, Markup & Margin
Free staffing bill rate calculator: turn a pay rate into a client bill rate with markup, reverse a bill rate into a pay rate, convert markup vs margin, and build a fully burdened labor rate. 100% private — runs in your browser.
Billion to Trillion Converter — Free Online Tool
Convert billions to trillions and trillions to billions instantly. Free 2-way converter with million and quadrillion support, quick tables, and short vs long scale explained.
BIMS Calculator — Brief Interview for Mental Status Score (MDS 3.0) | nrtechstudio.com
Free BIMS calculator: score the Brief Interview for Mental Status (CMS MDS 3.0 Section C) — repetition, temporal orientation, recall — total 0-15 with
BIN File Converter
Convert and inspect binary (.bin, .dat) files into Hex dumps, Base64, ASCII text, and C-array formats online.
Binary Code Translator & Base 2 Calculator
Precision binary code translator, translate binary to English, denary to binary calculator, hex to decimal, signed binary converter, and decimal binary hex chart.
Binary Converter
Convert text to binary and decode binary to text.
Binary Decoder – Binary to English, ASCII Code Generator
Binary decoder, binary to English, ASCII code generator, words to binary, binary numbers base 10, convert bytes, binary code encoder, image to binary converter, symbols to binary.
Binary to Decimal Converter — Free Online with Place-Value Steps | nrtechstudio.com
Convert binary to decimal and decimal to binary free. Interactive place-value bead visualizer, step-by-step working, binary fractions, bit grouping. 100% private — runs entirely in your browser.
Binary to Hex Converter — Nibble Visualizer with Steps | nrtechstudio
Convert binary to hex and hex to binary with a live nibble visualizer, show-your-work steps, 0x prefix and byte-spacing options. Free, private, 100% client-side.
Binary to String Converter — Decode Binary to Text Online (UTF-8)
Free binary to string converter: decode 0/1 bits to text with per-byte breakdown, honest UTF-8 errors, and reverse text-to-binary. 100% client-side.
Binary To Text
Convert binary code back to ASCII text.
Binoculars Range Calculator — Mil-Dot & MOA Rangefinder Estimator
Estimate distance with binoculars or a riflescope: mil-dot range formula (range = size × 1000 ÷ mils), MOA variant, missing-variable solver, presets, and unit conversion. Free, no sign-up.
BIP39 Seed Phrase Generator & Mnemonic Validator
Free BIP39 mnemonic generator: create 12-24 word seed phrases with secure randomness, validate checksums, derive 512-bit seeds. 100% client-side.
Bird Age Calculator — Estimate Your Bird's Age (Budgie, Cockatiel, Lovebird, Canary)
Free bird age calculator: estimate your budgie, cockatiel, lovebird or canary's age from iris, cere, beak and plumage signs. Honest ranges, not fake exact ages.
Birdsmouth Cut Calculator
Free birdsmouth cut calculator: seat cut, heel cut, HAP, IRC notch limits, rafter length, hip/valley layout.
Birth Control Cost Calculator: Compare Method Prices With & Without Insurance | nrtechstudio.com
Free birth control cost calculator: compare what the pill, patch, ring, shot, implant, hormonal IUD, copper IUD, condoms, vasectomy, and tubal ligatio
Birth from Death Date Calculator - Birth Date & Year Range
Free birth-from-death-date calculator for genealogy: estimate birth date range and birth year from a death date and age at death, with age-at-death verifier. 100% client-side.
Birthweight Percentile Calculator — INTERGROWTH-21st by Gestational Age
Free birthweight percentile calculator using the INTERGROWTH-21st newborn size standards (LMS method). Enter gestational age, birthweight and sex to get percentile, z-score and SGA/AGA/LGA classification.
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Try a different keyword like "calculator", "planner", "converter" - or pick a category above.
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.