Whether you're trying to figure out if you can afford a house, how much your savings will grow, or just what 17.5% of 340 is — having a reliable, free calculator saves you time and mental energy every single day.
We've built a full suite of free calculators at EasyPDF Studio, and in this guide we'll walk through exactly what each one does, when to use it, and the maths behind it. No sign-up, no downloads, no nonsense.
1. Mortgage Calculator — Know Your Monthly Payment Before You Buy
A mortgage is likely the largest financial commitment you'll ever make, yet most people have no idea what their monthly payment will be until they're deep in the process. A good mortgage calculator changes that in seconds.
To calculate your monthly mortgage payment, you need three things: the loan amount (home price minus your down payment), the annual interest rate, and the loan term in years.
// M = monthly payment
// P = loan principal (home price − down payment)
// r = monthly interest rate (annual rate ÷ 12)
// n = total number of payments (years × 12)
For example, on a $350,000 home with a 20% down payment ($70,000 down, $280,000 loan) at 6.5% interest over 30 years, your monthly payment would be approximately $1,770 — and you'd pay around $357,000 in interest over the life of the loan.
15-year vs 30-year mortgage: which saves more?
| Term | Monthly Payment | Total Interest Paid | Total Cost |
|---|---|---|---|
| 30-year @ 6.5% | $1,770 | $357,000 | $637,000 |
| 15-year @ 6.0% | $2,365 | $145,700 | $425,700 |
A 15-year mortgage saves over $211,000 in interest — but your monthly payment is $595 higher. Whether that trade-off works depends on your budget and other financial goals.
2. Loan Repayment Calculator — Any Loan, Any Term
Personal loans, car loans, student loans — the repayment formula is always the same, but the inputs change. Our loan repayment calculator works for any amount, rate, and term combination.
The key number to watch isn't just the monthly payment — it's the total interest paid. A loan that feels affordable month-to-month can cost you far more than you realise over its full term.
How loan term affects total cost
| $15,000 @ 8.9% APR | Monthly Payment | Total Interest |
|---|---|---|
| 2 years | $685 | $1,440 |
| 3 years | $476 | $2,136 |
| 5 years | $311 | $3,660 |
Shorter terms hurt your monthly cash flow but save significant money overall. The right balance depends on your current income and expenses.
3. Compound Interest Calculator — Watch Your Savings Multiply
Albert Einstein allegedly called compound interest "the eighth wonder of the world." Whether or not he said it, the principle holds: money earns interest, that interest earns more interest, and over decades the effect is extraordinary.
// A = final amount
// P = initial deposit
// r = annual interest rate
// n = compounding periods per year
// t = years | PMT = monthly contribution
The real power of compound interest reveals itself over long timeframes. Someone who invests $5,000 today with $200/month at 7% annual return will have:
Total contributed over 30 years: $77,000. Total growth from interest alone: $335,000. That's the compounding effect at work.
4. VAT Calculator — Add or Remove Tax in One Click
Value Added Tax (VAT) trips people up constantly — especially when a price is quoted excluding VAT and you need to know the real amount, or when you need to extract the VAT portion from an inclusive price.
The two calculations everyone gets confused
Adding VAT (you have the net price): Multiply by 1.20 for 20% VAT, or 1.05 for 5% VAT.
Removing VAT (you have the gross price): Divide by 1.20 for 20% VAT, or 1.05 for 5% VAT. A common mistake is subtracting 20% — this gives the wrong answer because VAT is calculated on the net, not the gross.
5. Percentage Calculator — The One You'll Use Every Day
Percentages appear everywhere — discounts, tax rates, test scores, salary increases, investment returns, tips. Yet "what is X% of Y?" causes a surprising amount of mental friction for most people.
Three questions the percentage calculator solves instantly:
- What is X% of Y? (e.g. what is 15% of £340?)
- X is what percentage of Y? (e.g. 51 is what % of 200?)
- Percentage change from A to B? (e.g. price went from £80 to £100 — what's the increase?)
6. BMI Calculator — A Quick Health Benchmark
Body Mass Index (BMI) is a simple ratio of weight to height squared. It's not a perfect health metric — it doesn't account for muscle mass, bone density, or body composition — but it remains a widely used screening tool.
// Example: 70kg ÷ (1.75 × 1.75) = 22.9 (Healthy Weight)
| BMI Range | Category | Health Risk |
|---|---|---|
| Below 18.5 | Underweight | Elevated |
| 18.5 – 24.9 | Healthy Weight | Low |
| 25.0 – 29.9 | Overweight | Moderate |
| 30.0 and above | Obese | High |
7. Age Calculator — Exact Years, Months and Days
Knowing someone's age to the exact day matters more than you'd think — for legal documents, insurance applications, medical records, or just satisfying curiosity about how many days old you actually are.
Our age calculator gives you the precise breakdown: years, months, and days between any two dates, plus your total days lived and how many days until your next birthday.
8. Tip & Bill Splitter — End the Restaurant Maths Forever
Splitting a bill at a restaurant shouldn't require a group debate. Our tip calculator lets you enter the total, choose a tip percentage, and instantly see what each person owes — tip included.
Tipping norms vary by country. In the US, 15–20% is standard for sit-down restaurants. In the UK, 10–15% is typical. In many European and Asian countries, tipping is not expected at all.
| Bill: $85 for 3 people | Tip Amount | Per Person |
|---|---|---|
| 10% tip | $8.50 | $31.17 |
| 15% tip | $12.75 | $32.58 |
| 20% tip | $17.00 | $34.00 |
Mortgage, loan, VAT, BMI, compound interest, percentage, age, and tip — all free, all instant, all private.
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