Home
TCalc.itTCalc.it Help Center

TCalc.it Help

Everything you need to know about TCalc.it - from basic time arithmetic to advanced converters and output formats.

What Is TCalc.it?

TCalc.it is a time-aware calculator that understands the difference between a point in time (dates) and an amount of time (durations). Type natural expressions like "2h + 30m" and get instant results.

Your First Calculation

Type an expression into the input field, then press Enter or = to calculate. Try: "2h + 30m". The result appears instantly below the input.

2h + 30mAdd 2 hours and 30 minutes → 2h 30m
1d - 2hSubtract 2 hours from 1 day → 22h
Add & Subtract Durations

Combine time durations using + and - operators. You can mix any units freely.

2h + 30mAdd 2 hours and 30 minutes
1d - 2hSubtract 2 hours from 1 day
3W + 2d + 8hCombine weeks, days, and hours
8h + 8h + 8h + 8h + 8hSum a work week from daily logs
Date Differences

Subtract two dates to find the duration between them, or write a range with "to" (aliases: until, till). Use keywords like NOW, TODAY, TOMORROW, YESTERDAY, or type specific dates.

NOW - 01.01.1990How long since January 1st, 1990 (your age?)
NOW - 01.01.2025Time elapsed since start of 2025
TOMORROW - NOWTime remaining until tomorrow
31.12.2025 - TODAYDays until end of year
14:30 to 16:45Duration between two times
22:00 to 6:00Overnight range wraps to the next day → 8h
Mix Dates & Durations

Add or subtract durations from specific dates to find future or past dates.

NOW + 2dDate/time 2 days from now
01.06.2025 - 3M3 months before June 1st
TODAY + 1Y + 6M1.5 years from today
TODAY + 90dDeadline 90 days from now
Multiply & Divide

Scale durations by multiplying or dividing with numbers.

1h30m * 3Triple a duration (e.g. 3 identical tasks)
8h / 2Split evenly between 2 people
40h / 5Daily average from a weekly total
Supported Time Units
Y Years
Q Quarters (3M)
M Months
W Weeks (7d)
WD Work Days (8h)
d Days (24h)
h Hours
m Minutes
s Seconds
ms Milliseconds
f24 24fps Frames
f30 30fps Frames
f Default FPS Frames

The unit follows the number (2h 30m). Switch Unit position in Settings → Display to write it first as well: Y1M2 is 1 year 2 months.

Date & Time Inputs

Keywords

NOW Current date & time
TODAY / TDY Today at midnight
TOMORROW / TMRW Tomorrow
YESTERDAY / YEST Yesterday

Date formats

DD.MM.YYYY · DD.MM. (current year) · YYYY-MM-DD · DD/MM/YYYY

Time formats

HH:mm · HH:mm:ss · 9AM · 9:30PM

Time ranges

14:30 to 16:45 - duration between two times (aliases: until, till). Overnight ranges like 22:00 to 6:00 wrap to the next day.

UNIX Timestamps

1234567890UNIX - or any 10-digit number is auto-recognized as UNIX timestamp.

FPS Timecodes

HH:MM:SS:FFfXX - e.g. 01:00:00:12f24 (1 hr + 12 frames @ 24fps)
Reading 17:30 and 1730

By default a colon string is a time of day and a bare four-digit number is just a number: 17:30 is half past five in the afternoon, 1730 is one thousand seven hundred and thirty.

When it fails, fix it from the hint

11:34:30 + 15:03 adds two times of day, which has no answer. A hint appears over the keys explaining the reading and offering the other one: for a two-part string you pick minutes:seconds or hours:minutes, for a three-part string you switch HH:MM:SS to a length. One tap recalculates the same expression, no retyping.

You always see the active reading

While a duration reading is on, an amber label sits on the display, for example MM:SS + HH:MM:SS AS LENGTH. No mode is ever silently answering a different question than the one you typed.

The same switches live in Settings (Video tab for colon strings, Military tab for bare 1730), and every profile carries its own choice: Film reads 15:03 as 15m 3s, Military and Aviation read 1730 as 5:30 PM.

Keyboard Shortcuts
Enter / =Calculate expression
EscapeClear input
BackspaceDelete last character
0-9, .Insert numbers / decimal
+ - * /Insert operators

When the input field is not focused, pressing any key automatically focuses it and starts typing.

Ready to try it out?

Open TCalc.it - it's free