Calculators

Everyday math, money, date, and time calculations with clear formulas and explicit edge-case handling.

Tools in this category

Open any tool to use it. Nothing is installed or uploaded.

Percentage Calculator

Find X% of a number, work out what percent one number is of another, and calculate increases or decreases.

Discount Calculator

Work out the sale price, discount amount and total savings from one or two stacked percentage discounts, with optional sales tax.

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Age Calculator

Calculate an exact age in years, months and days from a date of birth, with total months, weeks, days and the next birthday.

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Date Calculator

Add or subtract years, months, weeks and days from a date, or calculate the exact difference between two dates.

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Time Card Calculator

Track a week of shifts with breaks, overnight hours, overtime and an optional hourly rate.

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Average Calculator

Calculate the mean, median, mode, range and standard deviation for a list of numbers.

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Ratio Calculator

Simplify a ratio, find a missing value, scale a ratio to a total and split an amount proportionally.

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Tip Calculator

Calculate the tip, total bill and per-person amounts, with tax-aware tipping and bill splitting.

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About this category

The calculators in this category cover the arithmetic people actually need day to day: percentages, discounts, ages, dates, time cards, averages, ratios, and tips. Each one is a standalone page with its own URL, the formula it uses, and a worked example you can reproduce by hand.

Every calculation runs in your browser. Nothing is submitted, stored, or logged, so it is safe to paste prices, working hours, or personal dates.

Percentage and discount math, including stacked discounts and sales tax.
Date and age arithmetic that follows calendar rules instead of treating every day as 24 hours.
Work-hour totals with breaks, overnight shifts, and an optional hourly rate.
Averages, ratios, and tip splitting with rounding rules stated up front.

Frequently asked questions

Are these calculators free to use? +

Yes. There is no account, no paywall, and no usage limit. The site is supported by advertising that is kept outside the tool area.

Do you store the numbers I enter? +

No. Calculations run in your browser and inputs are never sent to a server. Reloading the page clears the values you typed.

Which calculator should I use for a percentage change? +

Open the Percentage Calculator and choose the "Percentage change" mode. It reports the direction (increase or decrease) and handles a zero starting value explicitly instead of showing infinity.