Category guide
Calculation
Convert timestamps and units, solve percentages and tax, and split a tip. Enter the values you know and read the missing ones.
Made for: Anyone checking a bill, a measurement, a tax rate, or a Unix timestamp.
Tools in this category
Epoch Converter
Translate Unix timestamps into human-readable dates, and dates back into epoch time.
Percentage Calculator
Solve percentages, discounts, sales tax, and VAT from any two values.
Interest
Project compound growth, regular savings, or a loan payment from a rate and a term.
Number Base
Convert a number between decimal, binary, hexadecimal, octal, and Base64.
Aspect Ratio
Read a pixel size as a ratio, then scale the other side so the layout stays proportional.
Cron Parser
Read a cron expression as a sentence and list the next run times.
Data & Bandwidth
Convert storage sizes and transfer rates, from MB and GB to Mbps and MB/s.
Unit Converter
Convert length, mass, volume, temperature, and other common units.
Tip Calculator
Calculate a restaurant tip and split the total across any number of people.
Typical workflow
- 01
Pick the calculator
Epoch for time, Unit Converter for measurements, Percentage for rates and tax, Tip for a shared bill.
- 02
Enter what you know
Type the timestamp, measurement, prices, or bill. Leave the field you want solved empty when the tool supports that.
- 03
Set the context
Choose units, a time zone, a tax region, a tip preset, or the number of people.
- 04
Read every result
The page fills the related values: local time, every unit in the category, tax, or each person's share.
Best practices
- Epoch Converter accepts seconds, milliseconds, microseconds, and nanoseconds. Check the unit before you trust the date.
- Percentage discount solves from any two of price, percent, amount, and final price.
- Round each tip share up when you want a whole-number payment.
Privacy & limits
Calculators send the numbers you enter to the DevStack API and return the result. They do not require an account.
Frequently asked questions
Which time zones does Epoch Converter use?
UTC and your selected local zone, including WIB, WITA, and WIT.
Can Unit Converter show more than one result?
Yes. The chosen conversion is highlighted, and the same value is listed in every unit of that category.
Ready to try Calculation tools?
Open the category to launch any tool.