10 guides
Guides
The thinking behind the numbers. Each guide explains a formula or unit properly, shows the data in a chart you can save, cites primary sources, and links to the calculator that does the arithmetic.
BMI vs. body-fat percentage: why a “healthy” BMI can still be unhealthy
BMI is a screening ratio of weight to height; body-fat percentage measures composition. Here is where they agree, where they disagree, and how to use both.
How much protein do you really need? What the research says, in grams
0.8 g/kg prevents deficiency; 1.6–2.2 g/kg builds and keeps muscle. Here is how to pick your number and split it across the day.
EMI explained with an amortisation table: why early payments are mostly interest
A full amortisation walk-through of a 1,000,000 loan at 12% — with the month-by-month table and a tenure comparison that shows where the interest really goes.
Feet and inches to cm: the complete height conversion chart (4′0″ to 6′11″)
Every height from 4′0″ to 6′11″ in centimetres and metres, with the exact method behind the numbers and the mistakes that cause most wrong conversions.
Kg to lbs chart for body weight and gym plates (with stone)
A body-weight chart from 40 to 150 kg in pounds and stone, a plate-by-plate gym table, and the mental shortcut that gets you within 1%.
Celsius to Fahrenheit: the oven temperature chart every baker needs
Every standard oven setting in Celsius, Fahrenheit, gas mark and fan-oven equivalent, plus the formula and quick mental anchors for weather and body temperature.
Why your 1 TB drive shows 931 GB: decimal vs. binary storage units
The drive is fine — the units disagree. A clear explanation of GB vs GiB, with a table showing what every common drive size actually reports.
Percentage change vs. percentage points: the mistake in most headlines
From 5% to 7% is +2 points and +40% at the same time. Which one a headline chooses changes the story — here is how to read them correctly.
Tipping guide by country: how much to leave at restaurants around the world
Tipping ranges from mandatory to mildly insulting depending on where you are. A country-by-country table, the service-charge trap, and how to split a bill without arguments.
Sleep cycles: is 6 hours better than 7? What the 90-minute rule actually says
The 90-minute rule is a useful planning tool, not a law of nature. What sleep cycles are, where the rule helps, and where it is misused to justify short sleep.
New guides are added as calculators are reviewed. Every article is written by the CalculatorCamp editorial team, checked against the sources listed at the end of the piece, and dated so you can see when it was last revised. Spotted an error or a missing topic? Tell us.