Borrowing
Loan Calculator Guide
Understand amortisation math before you sign a personal, car or student loan.
- Monthly repayment formula
- Interest vs principal over time
- How term length changes totals
Guidance
Calculator Guides
Every calculator on QuickCalc ships with a plain-language explainer covering the inputs, formulas and best practices for interpreting the output. Use the guides below to understand the maths before you make a financial, health or planning decision.
- Step-by-step walkthroughs of the exact equations we implement.
- Use-case tips so you can apply the result in the real world.
- Links back to each calculator for instant hands-on practice.
Life planning
Age Calculator Guide
See how we compute exact age in years, months, days and countdown to the next birthday.
- Calendar-based Y/M/D maths
- Countdown to milestones
- Life expectancy visualisation
Investing
Compound Interest Guide
Learn the compounding formula and the impact of recurring deposits on future value.
- A = P(1 + r/n)^{nt}
- Contribution growth vs. interest
- Comparing compounding frequencies
Health
BMI Calculator Guide
Understand the BMI equation, body-fat estimate and how to interpret categories.
- Metric and imperial inputs
- Body-fat approximation
- Healthy weight ranges
Scheduling
Date Difference Guide
Learn the ISO 8601 rules we use to count exact days, weeks and months.
- UTC-safe date maths
- Timeline visual cues
- Handling leap years
Everyday money
Tip Calculator Guide
Get the tipping formula plus etiquette guidance for group bills.
- Tip percentage math
- Per-person splits
- Regional tipping norms
Operations
Business Days Guide
See how we skip weekends and optional holidays to get accurate workday counts.
- Weekend + holiday removal
- Country-aware calendars
- Timeline breakdowns