Fast, private developer tools
Convert CSV, merge PDFs, format JSON — every tool runs in your browser. Nothing is uploaded, and nothing is stored.
Most-used tools
- csvCSV → JSON
Paste or drop a CSV and instantly get structured JSON. Smart numeric coercion, pretty-print, and copy/download.
- jsonJSON Formatter
Pretty-print messy or minified JSON with adjustable indent (2 / 4 spaces or tabs) and an optional 'sort keys alphabetically' mode. Copy or download the result, all in your browser.
- pdfMerge PDF
Combine 2 or more PDFs into a single document, in your chosen order. Preserves original pages exactly.
- textWord Counter
Live word, character (with/without spaces), sentence and paragraph counts, plus estimated reading and speaking time and a keyword-density breakdown. Runs entirely in your browser.
- document-formattingPages ↔ Words
Turn a page count into a word count at your font, size and line spacing, with quick answers for 1, 2, 3, 5, 10 and 20 pages and the arithmetic shown.
- document-formattingWord Count Checker
Paste an essay and see words, characters, sentences, paragraphs, words per sentence, reading time and pages update live — with a pass, under or over verdict against your limit.
Categories
- CSV Tools33 ready
Fast, private browser-based tools for working with CSV files.
- JSON Tools33 ready
Validate, format, and convert JSON instantly in your browser.
- PDF Tools8 ready
Merge, split, reorder, and convert PDFs without uploading them.
- Image Tools25 ready
Compress, convert, crop, and edit images privately in your browser.
- Text Tools25 ready
Format, transform, and analyze text quickly.
- YAML Tools26 ready
Validate, format, and convert YAML config files in your browser.
- Date & Time Tools34 ready
Convert timestamps, calculate date differences, and work with timezones.
- Units & Numbers Tools33 ready
Convert units and work with numbers — length, weight, temperature, and more.
- Security & Crypto Tools37 ready
Hashes, checksums, UUIDs, passwords, and tokens — generated locally.
- Generators16 ready
Generate QR codes, barcodes, passwords, and placeholder data instantly.
- Markdown Tools17 ready
Format, convert, and validate Markdown — tables, TOCs, badges, and more.
- Web & Networking Tools14 ready
IP lookup, DNS tools, URL parsers, and HTTP utilities — all in your browser.
- Color & Design Tools13 ready
Convert color formats, generate palettes, CSS gradients, and test accessibility.
- Encoding & Number Bases20 ready
Base64, Base32, Base58, hex, binary, Morse code, classical ciphers, and character encoding converters.
- Finance & Business Tools23 ready
Loan calculators, interest, tax, ROI, and business math — client-side.
- SEO & Web Content Tools12 ready
Meta tag checkers, JSON-LD generators, UTM builders, and more.
- Math & Statistics Tools12 ready
Scientific calculator, prime numbers, matrices, statistics, and more.
- Geo & Location Tools18 ready
Coordinate converters, distance, bearing and midpoint calculators, geohashes, MGRS, Plus Codes, and lookups.
- Regex & Pattern Tools11 ready
Test, explain, generate, and optimize regular expressions.
- Audio & Video Tools27 ready
Trim, convert, and edit audio and video files — processed entirely in your browser.
- Archive & Compression Tools22 ready
Zip, unzip, split, and inspect archives and files — nothing leaves your browser.
- Code Formatter Tools24 ready
Format, minify and inspect HTML, CSS, SQL, JavaScript and more — right in your browser.
- Git & Dev Utility Tools24 ready
Generate .gitignore and CODEOWNERS files, lint commits, read diffs and handle everyday Git chores — in your browser.
- XML Tools26 ready
Format, validate, query and convert XML documents — in your browser, with nothing uploaded.
- Legal & Compliance Generators24 ready
Generate privacy policies, contracts, disclosures and compliance notices from a form — fill in your details, get ready-to-paste text.
- Geometry & Measurement Calculators38 ready
Area, perimeter, volume and coordinate geometry calculators with live diagrams.
- Coordinate Geometry Calculators13 ready
Plot points and lines, and find slope, intercepts, distances and equations.
- Number Theory & Statistics Calculators33 ready
Mean, median, mode, spread, percentiles, primes, divisors and sequences — one calculator per question.
- Algebra Calculators17 ready
Solve equations, factor polynomials, work with inequalities, variation and logarithms — with the working shown.
- Statistics & Probability Calculators19 ready
Probability, distributions, confidence intervals, correlation and regression — one calculator per question.
- Calculus Calculators15 ready
Derivatives, integrals, limits, series, gradients, divergence and curl — with the working shown.
- Student & School Tools26 ready
Grade, GPA, attendance and study-planning calculators for students and teachers.
- Fractions & Math Manipulation Tools16 ready
Exact fraction arithmetic, ratios and number theory with every step of the working shown.
- Printable Generators18 ready
Generate graph paper, planners, charts, worksheets and flashcards you can print.
- Worksheet Generators7 ready
Generate printable practice worksheets with answer keys, for maths, fractions, decimals and algebra.
- Classroom & Teacher Utilities13 ready
Randomisers, timers and grading helpers for the classroom — no accounts, nothing uploaded.
- Student Scheduling & Time Tools13 ready
Timetables, countdowns and study planners that count school days, not calendar days.
- Paper & Document Formatting Tools16 ready
Words per page, paper sizes, print scaling, bleeds, booklets and citation layouts.
- Text Analysis Tools19 ready
Reading speed, book completion times, sentence and paragraph structure, and the five readability formulas.
- Typing & Keyboard Tools10 ready
Typing speed and accuracy tests, guided practice, the words- and keystrokes-per-minute arithmetic, and four live keyboard diagnostics.
- Chemistry Calculators21 ready
Molar mass, moles, solutions, gas laws and equation balancing — every answer with its working shown.
- Physics Calculators22 ready
Kinematics, forces, energy, electricity, waves and fluids — with units per field and the working shown.
- Home & DIY Calculators19 ready
Material and measurement calculators for the house and yard — paint to concrete, stairs to roof pitch.
- Construction & Engineering Calculators14 ready
Beam, bolt, pipe, tank, flow, pressure and heat calculations — textbook formulas with the working shown.
- Electrical Calculators12 ready
Ohm's law, resistor colour codes, capacitors, inductors, dividers, batteries and wire sizing — with the parts you can actually buy.
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Frequently asked questions
Is DataToolsLab free?
Yes — every tool is free to use, with no signup or account required.
Are my files uploaded to a server?
No. Every tool processes your files locally in your browser. We do not see or store your data.
Do the tools work offline?
Yes. After you visit a tool page once, the service worker keeps it available offline.
Can I bookmark or favorite a tool?
Use the star icon on any tool page to add it to your favorites. Your list is stored locally and never leaves your device.