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.
Roof Shingle Calculator — Bundles, Squares & Takeoff
Free roof shingle calculator: estimate bundles, roofing squares, ridge caps, underlayment & nails for any multi-plane roof. No sign-up, in-browser.
Roof Truss Calculator: Span, Count, Lumber Size & Cost
Free roof truss calculator: truss count, rafter length, lumber size from IRC span tables, snow load, heel height and cost estimate. 100% in-browser.
Root Canal Cost Calculator
Root canal cost by tooth type: front, bicuspid, molar. Endodontist vs general dentist fees, PPO insurance out-of-pocket, and RCT vs extraction plus implant.
Roth Conversion Calculator (Standalone)
Model Roth conversion taxes with verified 2026 IRS brackets. Fill-the-bracket optimizer, multi-year ladder, IRMAA & RMD impact, break-even analysis. Free.
SAT Score Calculator — Digital SAT Raw-to-Scaled, Superscore & Percentile
Free digital SAT score calculator: convert raw correct answers to scaled section scores with official College Board practice-test tables, plan a superscore, reverse-solve the raw score you need for a target, and look up percentiles. 100% client-side.
Screen Time Calculator for Kids — Daily Budget by AAP & WHO Guidelines
Free screen time calculator for kids: get a daily & weekly screen time budget by age from AAP/WHO guidelines, track actual usage vs. budget with a compliance score, and split the budget into education, entertainment & social time.
Septic Pumping Cost Calculator
Estimate septic tank pumping cost for 2026: national data by tank size, household load, lid access, and region, plus riser payback and when-to-pump guidance.
Septic System Installation Cost Calculator
Septic system installation cost estimator by type, soil, bedrooms and region. 2026 data: replacement mode, permit fees and a 10-year septic vs sewer comparison.
Shed Foundation Calculator
Free shed foundation calculator: size concrete block piers, gravel pad, slab or skid bases by shed size, soil and region, with material counts and costs.
Shiplap Calculator \u2014 How Much Shiplap Do I Need?
Free shiplap calculator: boards, lineal feet, waste, trim & cost for horizontal, vertical, or ceiling installs. Subtracts windows & doors. 100% free, no signup.
Shrimp Cook Time Calculator \u2014 Saut\u00e9, Grill, Boil, Steam & Doneness
How long to cook shrimp? Sauté, grill, boil, steam, bake & air fryer times by shrimp size (16/20–41/50), 120°F doneness checker, and full time charts.
Skylight Installation Cost Calculator (2026 Prices)
Skylight installation cost calculator (2026): fixed, vented, solar & tubular prices by size, roof type, glazing and labor, itemized per-skylight estimate.
Sleep Study Cost Calculator — Home vs In-Lab Prices & Insurance
Sleep study cost calculator: in-lab polysomnography ($1,000–$7,000+) vs home test ($150–$500). Estimate your cost with insurance deductible, copay & prior-auth.
Slow Cooker Conversion Calculator
Convert any oven recipe to slow cooker time: instant LOW and HIGH settings, slow-cooker-to-oven reverse, LOW↔HIGH swap, temp chart and food presets. Free.
Sod Installation Cost Calculator
Estimate sod installation cost for 2026 by grass type, lawn size, site prep, and labor. Get a project breakdown, per-sq-ft price, and DIY vs pro comparison.
Song Finder — Find a Song by Humming, Lyrics, or Description
Can't name that tune? Hum it, type the lyrics you remember, or say where you heard it — our free song finder matches your melody and builds exact searches. No app, no upload, 100% in your browser.
Song Key Finder
Free song key finder: type a song's chords to estimate its musical key, Camelot code, relative keys, key signature and capo transpose. In-browser.
Spearman's Rank Correlation Calculator — Spearman Rho, Ties Correction & Significance Test
Free Spearman's rank correlation calculator: compute Spearman's rho from two paired datasets with average-rank tie handling, the full rank table (d, d²), the t significance test with p-value, and a Spearman vs Pearson comparison — all in your browser.
Student Loan Forgiveness Calculator
Free student loan forgiveness calculator: estimate the PSLF timeline, compare IDR plans (PAYE, IBR, ICR, RAP), and model the 2026 tax bomb on forgiven balances.
Study Planner - Free Study Schedule Maker & Exam Planner
Free study planner: enter your courses, exam dates and daily study hours for an optimal day-by-day schedule with spaced repetition, Pomodoro sessions and progress tracking.
Stump Grinding Cost Calculator
Stump grinding cost calculator: estimate prices by stump diameter, depth, roots, access and region. Compare per-inch vs per-stump quotes and DIY rental.
Subscript Generator - Unicode Subscript Superscript Copy Paste
Convert text to subscript (H₂SO₄) and superscript (x²) Unicode characters. Free copy & paste generator for chemistry, math, Discord, Instagram. No signup.
Subscription Cost Calculator - True Monthly & Yearly Cost (Free)
Free subscription cost calculator: true monthly and yearly cost of every subscription. Project price creep, model cancel savings, compare to household averages.
Summer Camp Cost Calculator
Summer camp cost calculator: plan multi-week day, overnight and specialty camps, stack sibling, multi-week, early-bird discounts, plus a monthly savings target.
Tablecloth Size Calculator
Find the right tablecloth size for any table. Enter the table shape, dimensions and drop to get the exact size plus the nearest standard size.
Tattoo Cost Calculator — How Much Does a Tattoo Cost?
Tattoo cost calculator: estimate prices by size, style, color & placement. Sleeve, cover-up & small tattoo costs with tip and aftercare breakdowns.
Teen Car Insurance Cost Calculator — Estimate by Age, State & Discounts
Teen car insurance cost calculator: estimate premiums by age 16-19, gender, state, coverage and discounts. 2026 data, savings tips, state table and 13 FAQs.
Therapy Cost Calculator — How Much Does Therapy Cost?
Therapy cost calculator: estimate per-session rates, insurance copays, sliding-scale fees and online therapy prices. Compare 5 ways to pay and budget your year.
Tile Installation Cost Calculator
Tile installation cost calculator: price ceramic, porcelain, stone, glass & mosaic per sq ft - pattern waste, prep, grout, regional labor and DIY vs pro.
Timing Belt Replacement Cost Calculator
Timing belt replacement cost calculator: price belt-only vs full kit with water pump by vehicle class, dealer vs independent labor, and the cost of waiting.
Tire Replacement Cost Calculator (standalone)
Tire replacement cost calculator: estimate new tire prices by type, size and vehicle, plus mount, balance, TPMS, alignment and tax. Free, no signup.
Tone Generator - Free Online Frequency and Waveform Player
Free online tone generator: play any frequency from 20 Hz to 20 kHz with sine, square, triangle or sawtooth waves, plus sweep, binaural beats, note presets and Solfeggio tones. 100% in your browser.
Transmission Repair Cost Calculator
Estimate transmission repair cost by symptom, transmission type and vehicle class. Compare rebuild vs replacement, labor hours and the 50% repair-vs-sell rule.
Treadmill Pace Chart (Standalone)
Free treadmill pace chart and converter: mph/kmh to pace per mile and km, incline to flat-pace equivalents, printable speed chart, workout paces from your 5K, and a belt calibration checker.
Tree Removal Cost Calculator — Estimate by Height, DBH & Region
Tree removal cost calculator: estimate tree removal prices by height, trunk diameter, species, condition and region, with low-high ranges and add-ons.
Trip Planner
Free trip planner: build a day-by-day travel itinerary with activities, times, per-day costs, reorderable days, a packing checklist generator, and printable export. 100% client-side, no signup.
True Position Calculator
GD&T true position calculator: TP = 2×√(ΔX²+ΔY²) from basic and measured coordinates. Pass/fail vs tolerance, RFS/MMC/LMC bonus, batch CMM data, zone diagrams.
Tummy Tuck Cost Calculator
Free tummy tuck cost calculator: mini, full & extended abdominoplasty prices with muscle repair, financing payments, and recovery downtime planner.
Tutor Cost Calculator
Tutor cost calculator: 2026 hourly rates by credential, subject & format. Estimate weekly, monthly and yearly costs, compare platform vs direct booking.
Urgent Care Cost Calculator
Estimate urgent care visit costs by reason, add-ons, and region. Compare urgent care vs ER vs PCP vs telehealth vs retail clinic with insurance math.
Varicose Vein Treatment Cost Calculator 2026 — Estimate by Procedure & Insurance
Varicose vein treatment cost calculator 2026: estimate sclerotherapy, laser, RFA, VenaSeal, phlebectomy & stripping per leg, sessions, and insurance coverage.
Vector Projection Calculator — proj_b(a), Orthogonal Component & Scalar Projection
Free vector projection calculator: project vector a onto b (2D, 3D, or n-dimension) with proj_b(a) = ((a·b)/(b·b))·b, orthogonal component, scalar projection length, step-by-step working, 2D SVG diagram, and batch mode.
Vertical Curve Calculator — Parabolic Crest & Sag Solver
Free vertical curve calculator: crest and sag parabolic solver with elevations, high/low point, K-value, AASHTO sight distance check and profile plot.
Vinyl Siding Calculator — Material Takeoff: Squares, Panels, Trim & Cost
Free vinyl siding calculator: squares, panels, boxes, J-channel, starter strip & corner posts with waste. Gables, trim takeoff & DIY/pro cost estimates.
Vitamin D Calculator — Dose, Sunlight & 25(OH)D Estimator
Free vitamin D calculator: estimate your D3 dose from 25(OH)D blood levels and weight, plus sunlight estimator, food intake checker and IU to mcg converter.
Waist-to-Height Ratio Calculator
Waist-to-height ratio (WHtR) calculator: enter waist and height in cm or inches for your ratio, NICE-based risk band, healthy waist target and measuring guide.
Wallpaper Installation Cost Calculator
Wallpaper installation cost calculator: per-sq-ft installed cost by material, pattern waste, room shape, removal, and regional labor — plus DIY vs pro.
Water Damage Restoration Cost Calculator
Water damage restoration cost calculator: estimate cleanup cost per sq ft by category (Cat 1/2/3), materials, dry-out days and deductible. Free, instant.
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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.