Everyday calculators
Percentages, rule of three, discounts and tips, unit conversion, dates and geometry - locally in your browser, no upload.
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Discount Calculator
Work out locally the final price after a discount and how much you save - no upload, in your browser.
Tip Calculator
Work out locally the tip, total and share per person - no upload, right in your browser.
Percentage Calculator
Work out locally how much a percentage of a value is - plus increased and decreased, no upload.
Rule of Three Calculator
Solve the rule of three locally: from "A corresponds to B" you work out what belongs to C - plus value per unit, no upload.
Percentage Change Calculator
Work out locally the percentage change from an old to a new value - plus the difference and the factor, no upload.
Inverse Rule of Three Calculator
Solve the inverse rule of three locally: more of A means less result - more workers, less time. No upload.
Fuel Cost Calculator
Work out locally the fuel cost of a trip from distance, consumption and price - no upload, in your browser.
Energy Cost Calculator
Work out locally an appliance's electricity cost per day, month and year from power, usage and price.
Aspect Ratio Calculator
Work out the aspect ratio from width and height - reduced, as a decimal and with a proportional target height. Locally, no upload.
Pixel Density (PPI) Calculator
Work out pixel density (PPI) from resolution and screen diagonal - with dot pitch and megapixels. Locally, no upload, in your browser.
Circle Calculator
Work out the area, perimeter and diameter of a circle from its radius or diameter. Locally, no upload, in your browser.
Rectangle Calculator
Work out the area, perimeter and diagonal of a rectangle from its length and width. Locally, no upload, in your browser.
Triangle Calculator
Work out the area, perimeter and largest angle of a triangle from its three side lengths. Locally, no upload.
Length converter
Convert lengths locally between metric and imperial units like metre, kilometre, mile, foot and inch. No upload, in your browser.
Weight converter
Convert weights locally between tonne, kilogram, gram, milligram, pound and ounce. No upload, in your browser.
Temperature Converter
Convert temperatures locally between Celsius, Fahrenheit and Kelvin. No upload, in your browser.
Data Size Converter
Convert data sizes locally between byte, KB, MB, GB, TB and the binary units KiB, MiB, GiB. No upload, in your browser.
Unit Price Calculator
Compare two products locally by their unit price and instantly see which is cheaper and how much you save. No upload.
Date Difference Calculator
Work out the span between two dates locally: total days plus a breakdown into years, months and days. No upload.
Working Days Calculator
Count the working days between two dates locally: weekdays Monday to Friday minus public holidays. No upload.
Week Number Calculator
Find the ISO 8601 calendar week number for any date locally - with the ISO year, weekday and day of the year, no upload.
Wareki Calendar Converter
Convert Japanese era years (Reiwa, Heisei, Showa, Taisho, Meiji) to Gregorian years and back locally - e.g. Reiwa 7 = 2025. No upload.
Taiwan Calendar Converter
Taiwan Minguo (ROC, since 1912) years and the Chinese lunar calendar converted to Gregorian dates locally - and back again. No upload.
Hijri Calendar Converter
Convert Islamic Hijri dates (Umm al-Qura) to Gregorian dates and back locally - for holidays, contracts and appointments. No upload.
Thai Calendar Converter
The Thai Buddhist Era (B.E., 543 years ahead of the Gregorian calendar) converted locally - for documents and appointments. No upload.
Lunar Calendar and Zodiac
Find the Chinese lunar calendar date and the zodiac animal year for a Gregorian date locally - no upload.
Zakat Calculator
Work out Zakat (2.5%) on wealth above the Nisab threshold - using the gold or silver price YOU enter, locally in your browser, no upload.
Sales Tax Calculator
Work out US sales tax for any state - with a hint on the average combined state and local rate.
Age Calculator
Work out your exact age in years, months and days locally - from your birth date to today or to any other reference date. No upload.
GPA Calculator
Work out your GPA (Grade Point Average) locally from letter grades and credit hours - including a weighted variant for Honors/AP courses. No upload.
Shohizei Calculator (Japan)
Convert a price between including and excluding Japanese consumption tax - 10% standard or 8% reduced rate, no upload.
Currency Converter
Convert an amount between 24 currencies - using a locally stored, indicative rate table, fully offline and with no upload.
Which tool do I need?
| Input formats | Output formats | Tools |
|---|---|---|
| Form inputs (no file) | Discount Calculator | |
| Form inputs (no file) | Tip Calculator | |
| Form inputs (no file) | Percentage Calculator | |
| Form inputs (no file) | Rule of Three Calculator | |
| Form inputs (no file) | Percentage Change Calculator | |
| Form inputs (no file) | Inverse Rule of Three Calculator | |
| Form inputs (no file) | Fuel Cost Calculator | |
| Form inputs (no file) | Energy Cost Calculator | |
| Form inputs (no file) | Aspect Ratio Calculator | |
| Form inputs (no file) | Pixel Density (PPI) Calculator | |
| Form inputs (no file) | Circle Calculator | |
| Form inputs (no file) | Rectangle Calculator | |
| Form inputs (no file) | Triangle Calculator | |
| Form inputs (no file) | Length converter | |
| Form inputs (no file) | Weight converter | |
| Form inputs (no file) | Temperature Converter | |
| Form inputs (no file) | Data Size Converter | |
| Form inputs (no file) | Unit Price Calculator | |
| Form inputs (no file) | Date Difference Calculator | |
| Form inputs (no file) | Working Days Calculator | |
| Form inputs (no file) | Week Number Calculator | |
| Form inputs (no file) | Wareki Calendar Converter | |
| Form inputs (no file) | Taiwan Calendar Converter | |
| Form inputs (no file) | Hijri Calendar Converter | |
| Form inputs (no file) | Thai Calendar Converter | |
| Form inputs (no file) | Lunar Calendar and Zodiac | |
| Form inputs (no file) | Zakat Calculator | |
| Form inputs (no file) | Sales Tax Calculator | |
| Form inputs (no file) | Age Calculator | |
| Form inputs (no file) | GPA Calculator | |
| Form inputs (no file) | Shohizei Calculator (Japan) | |
| Form inputs (no file) | Currency Converter |