ToolsJam
Free online calculation tools and converters — multilingual, fast, and ad-free where you need them.
With ToolsJam you can run accurate calculations, convert units, and tackle academic, professional, or everyday tasks. Built for speed, clarity, and accessibility on every device.
Popular tools
Percentage Calculator - Calculate Percent of a Number
Percentage calculator for X% of Y, percent change, discounts, tips, tax, and reverse percentages. Get clear answers with formulas instantly.
Percentage Increase Calculator - Calculate Percent Growth
Percentage increase calculator to find percent growth or decline between any two values. Ideal for stock prices, salaries, and website traffic.
Grade Calculator - Calculate Academic Grades and GPA
Calculate GPA from letter or numerical grades with credit-hour weighting. Supports mixed grading systems and shows per-course letter grade conversions.
Final Grade Calculator - Weighted Course Grade
Calculate your final course grade from current performance and final exam score using weighted averages. Plan your exam strategy to hit your target grade.
Ideal Weight Calculator
Ideal weight calculator compares Devine, Robinson, Miller, Hamwi, and BMI-based reference weights with a simple frame-size adjustment.
Weight Loss Percentage Calculator
Weight loss percentage calculator shows how much body weight you have lost as a percentage, plus BMI change and weekly rate from start to current weight.
Mean Calculator - Calculate the Average of Any Number Set
Mean calculator finds the arithmetic average of any set of numbers. Enter your data to get the mean, sum, and count with the formula shown.
Standard Deviation Calculator - Sample & Population
Standard deviation calculator for sample and population data. Find standard deviation, variance, mean, sum, and range from a list of numbers instantly.
Variance Calculator - Sample & Population Variance
Variance calculator for sample and population data. Computes variance, standard deviation, mean, median, mode, and IQR from any list of numbers instantly.
Dice Probability Calculator - Exact & At Least Odds
Dice probability calculator: find exact, at-least, or at-most probabilities for any combination of dice with up to 10 dice and 20 sides per die.
Density Calculator – Mass, Volume and Density Formula
Calculate density, mass, or volume using ρ = m/V. Supports multiple units for physics, chemistry, engineering, and material science applications.
Voltage Divider Calculator
Calculate output voltage, current, and power dissipation for resistor voltage divider circuits. Essential for electronics engineers and students.
True Random UUID Generator - Bulk v4 & v7 UUIDs Online
Generate UUIDs with true randomness: atmospheric-noise seeding from RANDOM.ORG or local CSPRNG. Version 4 and time-ordered v7, single or bulk up to 1,000.
JWT Decoder - Decode & Verify JSON Web Tokens Online
Decode JWT header and payload instantly and verify HS256 signatures in your browser. Tokens never leave your device — a fast, private JWT inspector.
JSON Formatter & Validator - Beautify, Minify & Check JSON
Format, validate, and minify JSON online with clear error messages and adjustable indentation. Paste raw JSON and get clean output — private, in-browser.
CSV Viewer - Open & Search CSV Files Online, No Upload
Open CSV and TSV files in a sortable, searchable table right in your browser. Files are parsed locally and never uploaded — fast, free, and private.
Merge PDF Files Online - Combine PDFs in Your Browser
Combine multiple PDF files into one document in the order you choose. Merging happens entirely in your browser, so your PDFs are never uploaded anywhere.
Math Worksheet Generator - Printable Addition to Division
Generate printable math worksheets: addition, subtraction, multiplication, and division with number ranges, problem counts, and an answer key included.
Browse by category
Math
Free online math calculators for algebra, geometry, calculus, fractions, and percentages — fast, accurate tools for students, teachers, and daily use.
- Chinese Remainder Theorem Calculator - CRT Solver
- Characteristic Polynomial Calculator - 2 by 2 Matrix
- Change of Base Formula Calculator - Log Converter
Biology
Free biology calculators for genetics, ecology, population growth, and cell biology. Quick tools for students, researchers, and life-science courses.
- Lawn Mowing Cost Calculator - Price Estimate
- How Big Will My Cat Get Calculator - Adult Size
- Horse Weight Calculator - Equine Estimate
Statistics
Free statistics calculators for probability, regression, hypothesis testing, and descriptive stats. Analyze data quickly with accurate online tools.
- Lognormal Distribution Calculator - PDF and CDF
- Log-Rank Test Calculator for Survival Analysis
- Linear Regression Calculator - Line of Best Fit
Finance
Free finance calculators for loans, mortgages, interest, taxes, investments, and budgeting. Make smarter money decisions with fast, accurate tools.
- Loan Calculator - Monthly Payment & Interest
- 10/1 ARM Calculator - Mortgage Payments
- 12-Hour Shift Pay Calculator - Overtime Pay
Conversion
Free online unit converters for length, weight, temperature, currency, time zones, and more. Convert between metric and imperial units instantly.
- Ares to Hectares Converter for Land Area
- Area Converter for Metric and Imperial Units
- Angstrom to Nanometer Converter for Wavelengths
Construction
Free construction calculators for concrete, materials, roofing, flooring, and project costs. Plan and estimate building projects with confidence.
- Concrete Column Calculator for Axial Capacity
- Concrete Driveway Cost Calculator
- Concrete Tube Estimator for Volume and Cost
Developer Tools
Free online developer tools: UUID generator, JWT decoder, JSON formatter, Base64, hash generator, regex tester, and more. Fast, private, in-browser.
- True Random UUID Generator - Bulk v4 & v7 UUIDs Online
- JWT Decoder - Decode & Verify JSON Web Tokens Online
- Base64 Encoder & Decoder - Convert Text and Files Online
File Tools
View and convert files online without uploading: CSV, Excel, Word, SQLite viewers, PDF merge and split, image compression. Everything runs in your browser.
- CSV Viewer - Open & Search CSV Files Online, No Upload
- Excel Viewer - Open XLSX & XLS Spreadsheets Online Free
- Word Document Viewer - Open DOCX Files Online, No Upload
Education
Free printable worksheet generators: math practice, multiplication charts, handwriting and Chinese character tracing sheets for kids and teachers.
- Math Worksheet Generator - Printable Addition to Division
- Multiplication Chart Generator - Printable Times Tables
- Chinese Character Tracing Worksheets - Printable Practice
Music Tools
Free online music tools: metronome, drum machine, virtual piano, tap BPM, tone generator, voice recorder, audio converter, spectrum analyzer, and more. No download.
- Online Metronome - Free Metronome with Tap Tempo
- Tap BPM Counter - Find the Tempo of Any Song
- Tone Generator - Play Sine, Square & Sawtooth Tones
Other
Free online tools and calculators for everyday tasks — dates, text, random generators, percentages, and handy utilities for work, school, and home.
- Delay and Reverb Calculator - BPM and RT60
- Days Until Valentine's Day Calculator
- Days Until Fall Calculator - Autumn Countdown
Tools by role
Curated tool collections for the way you work and study.