Practical guides
What to know before you type the numbers, and what to decide with the result.
How mortgage payments are calculated β and why the first years are almost all interest
The amortization formula behind every mortgage payment, what changes when you add taxes and insurance, and how extra payments cut total interest.
Mortgage calculatorLoan calculator
Compound interest explained with real numbers β why starting 10 years earlier doubles the result
How compounding actually works month by month, the rule of 72, and a side-by-side of starting at 25 versus 35 with the same monthly contribution.
Compound interest calculatorSavings goal calculator
Loan amortization schedule explained β reading the table and using it to pay off debt faster
What each column in an amortization table means, how to find the balance at any month, and three ways to use the schedule to save interest.
Loan calculatorMortgage calculator
Percentage change vs percentage points β the mistake that makes headlines wrong
Why a rate going from 10 % to 15 % is both a 5-point and a 50 % increase, how to compute change correctly, and reversing a discount to find the original price.
Percentage calculator
BMI: what the number means, where the categories come from, and what it misses
How BMI is calculated, the WHO cut-offs, why Asian countries use lower thresholds, and when waist size or body-fat percentage matter more.
BMI calculatorCalorie & BMR calculator
How to count working days correctly for deadlines, deliveries and leave
The rules that trip people up: whether day one counts, what 'five business days' means on a Friday, and which holidays to exclude.
Working days calculatorDate difference & countdown
How much house can I afford? The 28/36 rule, down payment and the number lenders actually use
Turn your income into a realistic home price using debt-to-income ratios, then check the monthly cost with the mortgage calculator including taxes and insurance.
Mortgage calculatorSavings goal calculator
Exact age for forms and eligibility β how age is counted in the US, EU, Korea and Japan
When 'age on the date of application' is measured, how Korea's 2023 age law changed things, and why some countries count age by calendar year.
Age calculatorDate difference & countdown