How Many Days Between Two Dates
Subtract the earlier date from the later, minding month lengths and leap years. Here's how to count it, and whether to include both endpoints.
Lena Hoffmann · 3 min read
Guides & tutorials
Practical guides, how-tos and comparisons to get the most out of our free online tools.
October 21, 2025
Celsius to Fahrenheit: The Formula
Multiply by 9/5 and add 32. Here's the formula, the reverse, a quick mental shortcut, and the reference points worth committing to memory.
Lena Hoffmann · 2 min read
October 20, 2025
kg to lbs: Formula and Quick Table
Multiply kilograms by 2.2046 for pounds. Here's the exact factor, how to go back, a quick mental estimate, and a reference table.
Lena Hoffmann · 2 min read
BMR vs TDEE: What's the Difference?
BMR is what you burn at rest; TDEE is what you burn in a whole day. Here's how they relate, how the activity multiplier works, and which to use.
Sofia Nunes · 2 min read
JSON vs XML: What's the Difference?
JSON and XML both store structured data as text, but they trade off differently. Here's how each looks, where each wins, and how to choose.
Daniel Okonkwo · 2 min read
October 17, 2025
The 50/30/20 Budget Rule
Split after-tax income into 50% needs, 30% wants, 20% savings. Here's how the buckets work, what counts as each, and how to adapt it to your life.
Camille Laurent · 2 min read
cm to Inches and Feet
Divide centimetres by 2.54 for inches, or 30.48 for feet. Here's the formula, how to write a height in feet and inches, and a reference table.
Lena Hoffmann · 2 min read
What Is Base64 Encoding?
Base64 turns binary data into safe text. Here's what it does, why it exists, why it isn't encryption, and the size cost it adds.
Daniel Okonkwo · 2 min read
October 16, 2025
How Much Flooring Do You Need? (With Waste)
Divide the room's area by a pack's coverage, then add for cuts and waste. Here's the method, with an example and how much extra to buy.
Marco Bianchi · 3 min read
October 15, 2025
What Is VO2 Max?
VO2 max is the most oxygen your body can use during hard exercise — a benchmark of aerobic fitness. Here's what it means, typical values, and how to raise it.
Aisha Karim · 2 min read
How Many Calories Does Running Burn?
Running burns roughly your body weight in calories per kilometre. Here's the simple rule, what changes it, and how running compares to walking.
Aisha Karim · 2 min read
October 14, 2025
Roman Numerals Explained
Seven letters, added or subtracted. Here's what each stands for, how the subtractive pairs work, how to write any number, and where they still appear.
Lena Hoffmann · 2 min read