Free Online Calculators
Everyday finance, date and time calculators that give instant, accurate answers.
EMI Calculator
Calculate loan EMI, total interest and repayment.
Percentage Calculator
Calculate percentages, increases, decreases and ratios.
Compound Interest Calculator
Project savings growth with compound interest.
GST / VAT Calculator
Add or remove GST/VAT and see the tax amount.
Discount Calculator
Calculate sale prices and how much you save.
Profit Margin Calculator
Calculate profit, margin and markup from cost and price.
Age Calculator
Calculate your exact age in years, months and days.
Date Difference Calculator
Find the days, weeks and months between two dates.
Countdown Calculator
Count down live to any future date and time.
Leap Year Checker
Check whether any year is a leap year.
Free Online Calculators that respect your privacy
From working out a loan EMI or compound interest to calculating your exact age or the number of days until a deadline, our free calculators use transparent, standard formulas and update instantly as you type. They run entirely in your browser and work offline once loaded.
Every tool runs in your browser — nothing is uploaded.
Frequently asked questions
Are the calculations accurate?
Yes — we use standard, verifiable formulas and calculate in real time.
Do they work offline?
Once the page has loaded, the calculators keep working without a connection.
Explore more collections
Looking for something specific? Browse all Crystal Toolkit tools or view tools by category.