66 free tools · no sign-up · runs in your browser
Free Online Calculators & Converters
Health and fitness planners, money and math calculators with the working shown, converters and developer utilities. Clear answers, honest sources, nothing to install.
New
Health & Fitness
12 tools
Training plans, trackers and percentiles built on clinical data.
- Workout Plan GeneratorA 4, 8 or 12-week plan for your goal and equipment
- GLP-1 Weight Loss CalculatorWeek-by-week Wegovy & Zepbound forecast from the clinical trials
−48 lbin 72 weeks on Zepbound 15 mg
- BMI CalculatorYour BMI and the healthy weight range for your height
22.7 BMIhealthy at 154 lb, 5 ft 9 in
- Glucose to A1C ConverterAverage glucose to A1C and back, in mg/dL or mmol/L
5.4% A1C≈ 108 mg/dL average glucose
- Exercise LibraryEvery exercise by muscle, with rotatable 3D demos
- Guided Yoga FlowsFollow-along yoga with a 3D guide and breath-paced timer
Money
6 tools
Mortgages, loans, savings and big purchases, with honest verdicts.
- Mortgage CalculatorMonthly payment, total interest and your payoff date
- Compound Interest CalculatorWatch savings grow, reach a goal, or see the cost of waiting
$300,851$500 a month for 20 years at 7%
- Loan Prepayment CalculatorHow much sooner extra payments make you debt-free
12½ years soonerpaying $500 extra a month
- Prepayment vs Refinance CalculatorPay extra or refinance? A fair side-by-side verdict
Refinancesaves $42,882 more than paying extra
- Car Buy vs Lease CalculatorBuy or lease, with net cost and a check of the dealer quote
Buy$10,297 less than leasing over 5 years
- Solar Panel ROI CalculatorWhen solar pays for itself, from your bill and state
6.9-year paybackthen $61k ahead over 25 years
Math & Science
7 tools
Answers with the working shown, and units converted exactly.
- Percentage CalculatorPercent of, % change, difference and reverse percentages
- Base ConverterBinary, hex, octal, text and floats, with the working shown
1111 1111decimal 255 in binary
- Fraction CalculatorAdd, subtract, multiply and divide fractions, exactly, with every step
- Quadratic Equation SolverRoots, exact forms, steps and the parabola for ax² + bx + c
x = 2 or 3x² − 5x + 6 = 0
- Unit ConverterLength, weight, temperature, volume and more, at their exact definitions
- Math CalculatorPrimes, factors, GCF and LCM, averages, spread, powers and logs, worked out
- Physics Unit ConverterForce, energy, speed and power in every common unit
From Learn
Learn
7 tools
Courses you type along with, plus grades and worksheets.
- Linux Command Line LessonsLearn Linux commands by typing them in a practice terminal
- Final Grade CalculatorThe score you need on the final to hit your target
94%needed on the final for an 85%
- Python LessonsLearn Python by writing it, from first steps to how it really works
- GPA CalculatorSemester and cumulative GPA, weighted or unweighted
3.48GPA over 13 credits
- Turtle GraphicsLearn to code by drawing with a turtle
- Math Worksheet GeneratorPrintable math worksheets, new every time, with answer keys
- Grade CalculatorYour course grade from weighted assignments
Create
13 tools
Images, documents, boards and charts, made in your browser.
- Vision Board MakerA beautiful board for the year ahead, as a wallpaper or print
- PDF ToolsMerge, split, sign and convert PDFs without uploading them
- Image ConverterHEIC, WebP, AVIF, PNG and JPG to the format you need, in batches, with nothing uploaded
- Markdown EditorNotes in Markdown or block-based rich text, saved in your browser
- QR Code Scanner & GeneratorScan a QR code with your camera or from a screenshot and see where it really goes, or make one for a link, Wi-Fi or contact
- Photo EditorLayers, filters, text and crop, with nothing uploaded
From Learn
Tech
14 tools
Quick utilities, capacity math for engineers, and device checks.
- API Rate Limit CalculatorA per-client rate limit and burst, with ready-to-paste configs
- Device TestTest your mic, webcam, keyboard, click speed, space bar or controller, with nothing recorded or uploaded
- JSON ValidatorValidate, fix and format JSON, with a searchable tree and private history
- Regex TesterTest a regular expression live, with groups, replace and a plain-English explanation
- Cron Expression GeneratorRead a cron schedule in plain English, see its next runs, and write it for crontab, Quartz, AWS, GitHub or Kubernetes
- LLM Token Budget CalculatorMonthly cost of an AI feature across current models
From Learn
Time
7 tools
Timers that keep exact time, and dates worked out to the day.
- Pomodoro TimerFocus rounds and breaks, a task per round and today's count
- Interval TimerTabata, HIIT, EMOM and boxing rounds with countdown beeps
4:008 rounds: 20 s work, 10 s rest
- Online TimerSet a timer for any minutes, or use the stopwatch, alarm clock or a countdown to a date
- Time Zone ConverterConvert a time between any two places, see the time in a city now, or keep a world clock
- Focus TimerA work clock and a break clock: take your break whenever you need it
- Chess ClockTwo-player clock with increment, delay and blitz to classical presets
- Age CalculatorYour exact age, days lived and your next birthday