camelCase vs snake_case: A Guide to Naming Conventions in Code
camelCase, snake_case, PascalCase, and kebab-case explained: what each looks like, where it is the convention, and how to choose one consistently.
Daniel Okonkwo · 3 min read
Guides & tutorials
Practical guides, how-tos and comparisons to get the most out of our free online tools.
June 20, 2025
How Many Days Until a Date? (With Worked Examples)
Count the days until any future date, understand inclusive vs. exclusive counting, and build an accurate countdown you can trust.
Lena Hoffmann · 4 min read
June 19, 2025
Cat Years to Human Years: How to Calculate Your Cat's Age
A cat's first two years equal about 24 human years, then add roughly 4 per year. Learn the AAHA-backed method and see life-stage examples for kittens to seniors.
Marco Bianchi · 3 min read
mL to Cups: US, Metric, and UK Cups Explained
Convert milliliters to cups for cooking, with the key figure 1 US cup ≈ 237 mL, plus how the US cup, the metric cup, and the UK cup differ — and a ready-to-use table.
Daniel Okonkwo · 3 min read
June 18, 2025
How to Convert JSON to CSV: Flattening Arrays of Objects into Rows and Columns
A practical guide to turning a JSON array of objects into a clean CSV file, including how to flatten nested fields and handle the tricky edge cases.
Daniel Okonkwo · 4 min read
Percentage Difference vs. Percentage Change vs. Percentage Error
Three percentages that look alike but answer different questions. Learn the formula for each, when to use it, and why they give different numbers.
Lena Hoffmann · 3 min read
June 17, 2025
Tournament Brackets: Byes, Seeds, and Why the Numbers Must Be Powers of Two
A knockout bracket halves its field every round, so it only closes on a power of two. The bye count, the round count, the seed order and the total number of matches all follow from that one fact — and each is a one-line derivation.
Lena Hoffmann · 14 min read
mph to km/h: The Conversion Factor and Mental-Math Tricks
Convert miles per hour to kilometers per hour and back with the exact factor 1.609, common speed limits in both systems, and quick tricks you can do in your head.
Daniel Okonkwo · 3 min read
June 16, 2025
Splitting People Into Fair Groups: Random and Fair Are Not the Same Requirement
23 people do not divide into fours, and a uniformly random split can hand one group every strong player. Here is the remainder arithmetic, the measured cost of pure randomness, and the stratified fix.
Lena Hoffmann · 14 min read
June 13, 2025
Speed, Distance and Time: The Formula and How to Rearrange It
One triangle, three formulas. Learn speed = distance / time, rearrange it for distance or time, and keep your units consistent so the answer is right.
Marco Bianchi · 4 min read
June 12, 2025
Poker Hand Probabilities, Derived Rather Than Memorised
Every five-card poker probability is a counting argument over 2,598,960 hands, and each one fits on a single line. Here are all nine, with the check that proves them: the counts must sum to exactly C(52,5).
Lena Hoffmann · 13 min read
Dog Years to Human Years: The Real Formula (Not ×7)
The old "multiply by 7" rule is a myth. Learn the modern AVMA size-based method: dogs age fast early, then slower, and large breeds age quicker than small ones.
Marco Bianchi · 3 min read