Online Calculators
Free online calculators for age, percentage, average, discount, sales tax, simple interest and probability. Accurate answers instantly. Try them now!
Free Online Calculators โ Age, Percentage & Interest
Online calculators give fast, accurate answers for everyday maths โ from exact age and percentages to discounts, tax and interest.
All 8 Free Calculators
- Age Calculator โ Calculate your exact age in years, months and days from your date of birth.
- Percentage Calculator โ Calculate percentages instantly โ X% of Y, percentage change and what percent one number is of another.
- Average Calculator โ Find the average (mean) of a list of numbers instantly.
- Sales Tax Calculator โ Calculate sales tax, GST or VAT and the total price instantly.
- Discount Calculator โ Calculate the discount amount and final sale price instantly.
- Probability Calculator โ Calculate the probability of single and multiple events online.
- Simple Interest Calculator โ Calculate simple interest and total amount from principal, rate and time.
- Random Number Generator โ Generate random numbers within any range instantly.
How to Use These Tools
- Enter the required numbers or dates in the input fields.
- Select any options such as units or calculation type.
- Click the calculate button.
- Read the answer instantly and repeat with new values if needed.
Quick Reference
| Calculation | Formula |
|---|---|
| Percentage | Value ร Percent รท 100 |
| Average | Sum of values รท Count |
| Discount price | Price โ (Price ร Discount รท 100) |
| Price with tax | Price + (Price ร Tax rate รท 100) |
| Simple interest | Principal ร Rate ร Time รท 100 |
Why Use Our Calculators?
- Accurate formulas: Uses standard mathematical formulas for reliable answers.
- Instant answers: Results appear immediately after you click calculate.
- Free forever: The tool is free with no limits on use.
- No app needed: Runs in your browser on any phone or computer.
- Easy to read: Clear results that are simple to understand and share.
- Great for study and work: Useful for students, shoppers, teachers and professionals.
Tips
- Double-check the numbers you type โ most errors come from input mistakes.
- Use decimal points rather than commas for fractions.
- For money decisions, round the final value only at the end.
- Bookmark the calculator so it is ready when you need it.
Worked Example
Example: a jacket costs โน2,499 with 30% off. The discount is 2,499 ร 30 รท 100 = โน749.70, so the final price is โน1,749.30. If 18% tax is then added, multiply the discounted price by 0.18 and add the result.
Glossary
- Percentage
- A part of 100, written with the % sign.
- Mean (average)
- The sum of all values divided by how many values there are.
- Principal
- The original amount of money borrowed or invested.
- Rate
- The percentage charged or earned per period, usually per year.
- Probability
- How likely an event is, from 0 (impossible) to 1 (certain).
Helpful Guides
- How to Calculate Exact Age from Date of Birth
- How to Calculate Percentage: Formulas and Examples
- Simple Interest Explained: Formula, Examples and Uses
Frequently Asked Questions
Are these calculators free?
Yes. Every tool in this category is free to use on pdfseotools.com with no sign-up.
Do the tools work on mobile?
Yes. They work in any modern browser on Android, iPhone, Windows and Mac.
Is my data safe?
Yes. Connections use HTTPS and uploaded files are removed after processing.