Topics & guides
Every calculator on Calcxo is paired with explainers, comparisons, and ready-to-quote answers. Browse by intent below.
Conversion pairs
Direct conversions between two specific units or currencies.
- USD to EUR ConverterConvert US dollars to euros at the latest reference rate. Live conversion, reverse rate, and a clear note that rates are reference, not trading rates.
- EUR to USD ConverterConvert euros to US dollars at the latest reference rate. Reverse rate, live conversion, and a transparent note about reference vs trading rates.
- Feet to Meters ConverterConvert feet to meters with an instant calculation, the exact formula, and a quick reference table for common values.
Comparisons
Side-by-side breakdowns of two related concepts.
- Simple vs Compound InterestWhat's the difference between simple and compound interest? Side-by-side definitions, formulas, an example, and when each one applies.
- BMI vs Body Fat PercentageWhat's the difference between BMI and body fat percentage? Compare what each one measures, accuracy, and when to use each.
- APR vs APYWhat's the difference between APR and APY? Clear definitions, the relationship between the two, and which one to use when.
Definitions
Plain-English definitions for the terms behind each calculator.
- What Is BMI?BMI definition explained in plain English. What the number means, the standard ranges, the formula, and the limits of using BMI on its own.
- What Is APR?APR (Annual Percentage Rate) explained — what it includes, how it differs from interest rate and APY, and how to read it on loans and cards.
- What Is an Exchange Rate?Exchange rate definition — what it represents, how it's quoted, and the difference between mid-market and the rate your bank gives you.
Formulas
The math behind each calculator, explained variable by variable.
- Compound Interest FormulaThe compound interest formula explained, with each variable defined, a worked example, and the version with regular contributions.
- Percentage Change FormulaThe percentage change formula with a clear example. Works for both increases and decreases, with the sign telling you the direction.
- BMI FormulaThe BMI formula in metric and imperial units, with worked examples for both. Plain-English explanation of why height is squared.
How-to guides
Step-by-step instructions you can follow without a calculator.
- How to Calculate a PercentageThree quick methods to calculate any percentage, with worked examples and a calculator for the messy ones.
- How to Calculate Your BMIStep-by-step BMI calculation in metric and imperial units, with a quick interpretation of the result.
- How to Calculate a Mortgage PaymentHow to calculate a monthly mortgage payment by hand, including the formula, a worked example, and what's not included.
Worked examples
Specific 'how much is X% of Y' style answers, fully shown.
- What Is 15% of 200?15% of 200 is 30. See the one-line calculation, the formula behind it, and try the percentage calculator for any other number.
- What Is 20% of 50?20% of 50 is 10. Quick math, the formula, and a calculator if your numbers don't match.
- How Much Tip on $50?A 15% tip on $50 is $7.50. A 20% tip is $10. See the quick math and a calculator for any bill amount.
Common mistakes
The errors that trip people up — and how to avoid them.
Scenarios
Concrete real-world cases — payments, balances, projections.
- $300,000 Mortgage at 6.5% for 30 YearsWhat does a $300k mortgage at 6.5% cost per month? Full breakdown of payment, total interest, and what's not included.
- Investing $500 a Month for 30 YearsWhat does $500/month for 30 years grow into? See the projected balance at common return rates and how much came from contributions.
Quick answers
Short, direct answers to high-intent questions.