CalcLoft
Work & Time

Time Calculator

Result
2:15 AM
next day

Start from a time, then add or subtract hours and minutes; this calculator gives the resulting clock time and notes any day change. Add 3 hours 45 minutes to 10:30 PM and it returns 2:15 AM the next day. Subtract to roll backward. Useful for arrival times, deadlines, and shift planning where the clock wraps past midnight.

The formula

result = start ± (hours × 60 + minutes), wrapped to a 24-hour clock

Convert everything to minutes, add or subtract, then wrap into 0–1439 for the clock time. Each full 1,440-minute wrap is one day forward or back.

How to use it

  1. 1

    Enter the start time

    Type the time you're counting from in 10:30 PM or 22:30 form.

  2. 2

    Enter the amount to add or subtract

    Set the hours and minutes, then choose add or subtract. The amount can be larger than a day.

  3. 3

    Read the new time

    The result shows the new clock time and how many days forward or back it lands, so a wrap past midnight is never a surprise.

Frequently asked questions

Can I add more than 24 hours?
Yes. Adding 30 hours to a time advances it by one day and 6 hours, and the calculator reports the day offset alongside the new clock time.
How do I count backward in time?
Choose subtract. Taking 90 minutes off 12:30 AM rolls to 11:00 PM the previous day, with the day change shown.
Does it handle AM/PM?
Yes. Enter the start with AM or PM, or use 24-hour time; the result is shown on the same 12-hour clock for easy reading.

Related calculators

Part of Work & Time Calculators. Last updated 2026-06-14.