💰 Tip Calculator
🏷️ Discount Calculator
📅 Date Calculator
💼 Hourly Wage Converter
📈 Inflation Calculator
Five small calculators for money and dates
This page bundles the quick sums people otherwise do on a phone calculator or the back of a receipt: splitting a restaurant bill with a tip, checking what a sale price really comes to, counting days between two dates, turning a salary into an hourly rate (or the reverse), and seeing how much an amount would need to grow to keep pace with inflation. Pick a tab, fill in the fields and the result box appears under the form.
How to use each tab
- Tip: enter the Bill Amount, the Tip Percentage (15 by default) and how many people to Split Between, then press Calculate. You get the tip, the total, and both figures per person.
- Discount: enter the Original Price and the Discount (%), then Calculate to see the Savings and the Final Price.
- Date: in Date Difference mode choose a Start Date and End Date; in Add Days mode choose a Start Date and a number of Days to Add (use a negative number to go back in time). Both date fields start on today’s date.
- Wage: set Hours/Week and Weeks/Year first, then type whichever pay figure you know — annual, monthly, weekly or hourly. The other three fill in automatically as you type.
- Inflation: enter an Amount, a Start Year, an End Year and the Annual Inflation Rate you want to assume, then Calculate.
The formulas behind the results
Tip and discount. Tip = bill × tip% ÷ 100 and total = bill + tip; the per-person figures divide both by the number of people without rounding up. Savings = price × discount% ÷ 100 and final price = price − savings. Sales tax is not added.
Dates. Date Difference reports the number of calendar days elapsed between the two dates (order does not matter), plus the same span as whole weeks and leftover days. Add Days moves forward or back by calendar days, so month lengths and leap years are handled by the browser’s date functions; weekends and public holidays are not skipped.
Wages. Weekly pay = annual ÷ weeks per year, hourly = weekly ÷ hours per week and monthly = annual ÷ 12. With the defaults of 40 hours and 52 weeks, a year is 2,080 paid hours, so 50,000 a year works out to about 24.04 an hour and 4,167 a month. These are gross figures with no tax, overtime or unpaid leave.
Inflation. The calculator compounds a single constant rate: factor = (1 + rate)years. Moving forward in time the amount is multiplied by the factor; if the end year is earlier than the start year it is divided instead. For example, 1,000 at 3% from 2000 to 2026 (26 years) gives a factor of about 2.157, so the equivalent is 2,156.59, total inflation is 115.7% and purchasing power falls by 53.6%. The page does not download official price-index data, so the answer is only as good as the rate you enter.
Amounts are shown with a “$” sign and two decimals, but the arithmetic is the same for any currency. All five calculators run entirely in your browser; nothing you type is stored or sent anywhere.
Frequently asked questions
How do I stack two discounts, such as 20% off and then an extra 10%?
Run the Discount tab twice, using the first Final Price as the second Original Price. 100 becomes 80 and then 72, which is a 28% total saving — not 30%, because the second discount applies to the already-reduced price.
Does the day count include both the start and end date?
No. It counts days elapsed, so Monday to Tuesday is 1 day. If you need an inclusive count, for example for a hotel stay counted in days rather than nights, add one to the result.
What tip percentage should I use?
That depends on local custom. In the United States 15–20% is a common range for table service, while in many other countries service is included in the bill or tips are small. The calculator simply applies whatever percentage you type.
Which inflation rate should I enter?
The 3% default is only a placeholder. For a realistic figure, use the average annual consumer price inflation published by your country’s statistics office for the years you are comparing. Because a single average is compounded, year-to-year swings are smoothed out.
I changed Hours/Week — why did nothing happen?
The other fields recalculate from the pay figure you typed most recently. If you have not typed any pay figure yet, enter one and the rest will fill in using the new hours and weeks.