Updated for 2026 • All calculators free • No signup required
For everyday calculations in 2026, the most useful tools are a percentage calculator (X% of Y, percentage change), unit converter (metric to imperial), and discount calculator (sale prices). Boring Math covers all of these free with no account. For students, the GPA Calculator supports both US and UK grading systems. For travellers, the Currency Converter and Time Zone Converter handle international planning. All calculators are free with no signup.
Calculates percentages in all directions: what is X% of Y, X is what percent of Y, and percentage change between two numbers.
Best for: Anyone needing quick percentage calculations for work, school, or shopping.
Open calculator →Converts between metric and imperial units for length, weight, volume, temperature, and area.
Best for: Anyone converting between measurement systems.
Open calculator →Calculates the sale price after a percentage or fixed-amount discount, showing how much you save.
Best for: Shoppers wanting to quickly calculate sale prices.
Open calculator →Calculates tip amount and total bill, with options to split between multiple people.
Best for: Anyone dining out and wanting to calculate tip quickly.
Open calculator →Calculates exact age in years, months, and days from a date of birth, plus days until next birthday.
Best for: Anyone needing precise age calculation for forms, applications, or curiosity.
Open calculator →Calculates the number of days, weeks, months, and years between any two dates.
Best for: Anyone counting days between dates for deadlines, holidays, or project planning.
Open calculator →Converts between major world currencies using current exchange rates.
Best for: Travellers, online shoppers, or anyone dealing with foreign currencies.
Open calculator →Calculates grade point average from individual course grades and credit hours, supporting both US 4.0 and UK classification systems.
Best for: Students calculating their GPA for applications or tracking academic progress.
Open calculator →Converts time between any two world time zones, accounting for daylight saving time.
Best for: Anyone scheduling calls or meetings across time zones.
Open calculator →| Calculator | Best for | Free | No account needed | Updated 2025/26 |
|---|---|---|---|---|
| Percentage Calculator | Anyone needing quick percentage calculations for work, school, or shopping | Yes | Yes | Yes |
| Unit Converter | Anyone converting between measurement systems | Yes | Yes | Yes |
| Discount Calculator | Shoppers wanting to quickly calculate sale prices | Yes | Yes | Yes |
| Tip Calculator | Anyone dining out and wanting to calculate tip quickly | Yes | Yes | Yes |
| Age Calculator | Anyone needing precise age calculation for forms, applications, or curiosity | Yes | Yes | Yes |
| Date Difference Calculator | Anyone counting days between dates for deadlines, holidays, or project planning | Yes | Yes | Yes |
| Currency Converter | Travellers, online shoppers, or anyone dealing with foreign currencies | Yes | Yes | Yes |
| GPA Calculator | Students calculating their GPA for applications or tracking academic progress | Yes | Yes | Yes |
| Time Zone Converter | Anyone scheduling calls or meetings across time zones | Yes | Yes | Yes |
To find X% of Y, multiply Y by X and divide by 100. For example, 15% of 200 is 200 x 15 / 100 = 30. The Percentage Calculator handles this instantly, plus reverse calculations like "30 is what percent of 200" and percentage change between two values.
Common conversions: 1 inch = 2.54 cm, 1 mile = 1.609 km, 1 pound = 0.4536 kg, 1 gallon (UK) = 4.546 litres. The Unit Converter covers length, weight, volume, temperature, and area with instant results in both directions.
To find the sale price, multiply the original price by (1 minus the discount percentage). For example, 25% off £80: £80 x 0.75 = £60. To find the discount percentage from two prices, subtract the sale price from the original, divide by the original, and multiply by 100.
In the UK, 10-12.5% is standard for table service. In the US, 15-20% is typical. The Tip Calculator lets you set any percentage, shows the tip amount and total, and splits it evenly between multiple people if you are dining in a group.
The Date Difference Calculator gives you the exact gap in days, weeks, months, and years between any two dates. This is useful for counting down to events, calculating project durations, or working out notice periods and contract lengths.
Multiply each course grade by its credit hours, sum the results, and divide by total credit hours. On the US 4.0 scale, an A = 4.0, B = 3.0, C = 2.0. The GPA Calculator supports both US and UK grading systems and handles any number of courses.
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