Three-mode calculator: HH:MM time, standard, and date & time difference with persistent history.
Users
20
+3 in 30 days
Rating
5.0 / 5
unchanged in 30 days
Ratings
1
0 in 30 days
Store rank
#154K
#129K among extensions
Version
1.8
updated 30 Jun 2026
Users
monthly, 4 months
Latest, 21 Oct 2026:20 usersMove the mouse over the chart for any month
Ratings count
monthly, 4 months
Latest, 21 Oct 2026:1 ratingsMove the mouse over the chart for any month
The Chrome Web Store rounds user counts down to the leading digit, so the user line moves in steps. The ratings count is exact and is the better signal of real adoption.
About HH_MM_Tri_Calculator
HH Time Calculator by R. Carbonell combines three essential calculators into one easy to use Chrome extension: an HH Time Calculator, a Standard Calculator, and a Date & Time Calculator. Designed for aviation professionals and anyone who works with time, it makes it simple to calculate duty time, Flight Duty Period (FDP), rest periods, payroll hours, schedules, and everyday calculations, all from one convenient tool.
The HH:MM Time Calculator is designed for anyone who works with time every day. Whether you are tracking work hours, scheduling shifts, managing payroll, calculating project durations, or working in aviation, this extension helps you perform accurate time calculations quickly and easily.
Unlike standard calculators, which do not understand time formats, this extension is built specifically for working with hours and minutes. For example, 1 hour 30 minutes is not the same as 1.30 hours. The HH:MM Time Calculator eliminates manual conversions and provides accurate results directly in your Chrome browser.
In addition to the HH:MM Time Calculator, the extension now includes a Standard Calculator and a Date & Time Calculator, giving you three essential calculators in one convenient application. Whether you need basic math, time calculations, or date and duration calculations, everything is available from a single, easy to access interface.
For aviation professionals, these tools are especially useful for calculating Duty Time, Flight Duty Period (FDP), Rest Periods, report times, release times, and other scheduling calculations. Having all three calculators in one extension helps reduce errors and saves valuable time throughout the workday.
A new Pop Out feature also allows you to open the calculator in a separate window, making it easy to position anywhere on your screen while working in other browser tabs or applications.
WHAT IT DOES
The HH:MM Time Calculator lets you add, subtract, multiply, and divide time values using HH:MM format, decimal hours, or minutes. Simply enter your values, choose an operation, and receive accurate results instantly without manual conversions.
The included Standard Calculator handles everyday mathematical calculations, while the Date & Time Calculator makes it easy to calculate the difference between dates and times, add or subtract days, hours, and minutes, and determine durations.
KEY FEATURES
Three calculators in one extension
HH:MM Time Calculator
Standard Calculator
Date & Time Calculator
Perform time calculations
Add, subtract, multiply, and divide time values
Flexible input options
Enter time in HH:MM format (1:30)
Enter decimal hours (1.5)
Enter total minutes (90)
Values are automatically interpreted and converted
Smart auto conversion
Type 1.30 and it converts to 1:30
Supports both period and colon input formats
Live conversion display
View decimal hours and total minutes as you type
Date & Time calculations
Calculate elapsed time between dates and times
Add or subtract days, hours, and minutes
Quickly determine durations
Standard Calculator
Perform everyday arithmetic calculations within the same extension
Full keyboard support
Enter key for equals
Backspace to delete
Period or colon as time separators
Fast keyboard entry
Persistent calculation history
View previous calculations in the History panel
History remains available between sessions until cleared
Pop Out window mode
Open the calculator in a separate movable window
Position it anywhere on your screen for easier multitasking
Clean, organized interface
Scrollable History panel
Consistent layout for efficient workflow
AC button
Clears the current calculation and resets the calculator
WHO IS IT FOR?
This extension is ideal for anyone who regularly works with hours, minutes, dates, and durations — whether in aviation, healthcare, logistics, payroll, project management, or any field where accurate time tracking matters. If your work involves shift scheduling, crew rest requirements, billing hours, or project timelines, this tool was built with you in mind.
Whether you're calculating Flight Duty Periods (FDP), crew rest requirements, payroll hours, project timelines, or everyday math, the HH:MM Time Calculator by R. Carbonell gives you all the tools you need in one simple, convenient Chrome extension.