About Binary Decimal
Free calculators and tools that give a clear answer, show their working, and keep your data on your device.
- Health & Fitness
- Money
- Math & Science
- Learn
- Create
- Tech
- Time
- free tools
- 92
- free tools
- groups
- 7
- groups
- sign-ups needed
- 0
- sign-ups needed
- calculations run in your browser
- Local
- calculations run in your browser
At Binary Decimal, we’re passionate about making calculations easier and more accessible for everyone. We build free online calculators and tools that take a complex task, like converting between number systems, planning a mortgage or reading a lab result, and give you a clear answer in plain words.
Whether you’re a student tackling homework, a professional streamlining your workflow, or simply curious about the world of numbers, the right tool should be fast, honest about what it knows, and pleasant to use.
What we build
92 tools in 7 groups. Most open with a worked example, so you see an answer before you type anything.
Health & Fitness
23 toolsTraining plans, trackers and percentiles built on clinical data.
- Workout Plan Generator
- Exercise Library
- Guided Yoga Flows
- GLP-1 Weight Loss Calculator
- BMI Calculator
- TDEE Calculator
- VO2 Max Calculator
- Grip Strength Calculator
- Biological Age Calculator
- Glucose to A1C Converter
- Blood Sugar Log
- Kids Growth Calculator
- Bra Size Calculator
- Penis Size Percentile Calculator
- Penis Size Percentile Chart
- Due Date Calculator
- How Long Does Sex Last?
- GLP-1 Shot Journal
- Protein on a GLP-1
- Guided Meditation
- Sleep Calculator
- Workout Program Builder
- Practice Ledger
Money
10 toolsMortgages, loans, savings and big purchases, with honest verdicts.
Math & Science
8 toolsAnswers with the working shown, and units converted exactly.
Learn
7 toolsCourses you type along with, plus grades and worksheets.
Create
17 toolsImages, documents, boards and charts, made in your browser.
Tech
20 toolsQuick utilities, engineering math, device checks and AI tools.
- Device Test
- JSON Validator
- Encrypt & Decrypt
- Regex Tester
- Cron Expression Generator
- API Rate Limit Calculator
- AGENTS.md Checker
- JSON Schema Generator
- Agent Skill Checker
- LLM Token Budget Calculator
- Base64 Encoder/Decoder
- Password Generator
- ASCII Table
- System Latency Budget Calculator
- Kafka Message Size Calculator
- LLM Self-Hosted vs API Calculator
- Jira Story Points Calculator
- DORA Metrics Calculator
- Text Compare
- Resume Checker
Time
7 toolsTimers that keep exact time, and dates worked out to the day.
Where the numbers come from
The maths is standard, and most tools show how the answer was worked out. When a tool compares you with other people or turns one measurement into another, it uses published research and names it, so you can check it:
- Glucose ↔ A1Cthe ADAG study formula (Nathan et al., 2008)
- Kids growthWHO growth standards to age 2, CDC growth charts from 2 to 20
- GLP-1 weight lossthe STEP-1 and SURMOUNT-1 trial results
- Penis size percentileVeale et al. (2015), 15,521 men measured by clinicians
Health tools give information, not a diagnosis. If something on the site is wrong, we want to know and we fix it. Our editorial standards explain how tools are researched, tested and corrected.
Privacy: it runs in your browser
- Calculations happen on your device. What you type into a calculator isn’t sent to us.
- Your work stays in this browser. Notes, Markdown and Mermaid documents, vision boards and workout progress are saved locally, with no account.
- We count visits, not you. Google Analytics tells us which pages and features are used so we know what to improve; it never sees the numbers you enter.
The details are in our Privacy Policy and Terms of Use. Questions, bugs or ideas: use the contact form.
Start with a popular tool
Base converterMortgage calculatorWorkout plan generatorRead the blog