Clocks To The Hour. Clock math calculator from a selected clock time, add or subtract hours and/or minutes enter clock time information at from: enter hours and minutes. Set the hour, minute, and second for the online countdown timer, and start it.
If your grandfather clock is not striking exactly on the hour and the deviation is less than 15 minutes, you may adjust the minute hand to get it as close as you wish to an exact hour strike.
For the first hour of the day (12 midnight to 12:59 am), subtract 12 hours. Simply click and drag the movable hands. The day runs from midnight to midnight and is divided into 24 hours from 0 (midnight) to 23. The 12 hour clock splits the day into two 12 hour sections.
