Time format "10 to 10"

Can someone tell what does this time format "10 to 10" mean? Is it 9:50 or 10:10?


Solution 1:

The time "10 to 10" may also be stated as "10 minutes of 10", meaning 9:50. (From ngrams for minutes of 10,minutes to 10, the "to 10" form occurs several times as frequently as the "of 10" form.)

The last two examples on the "telling_time" webpage at eslgold.com illustrate the conventional meaning of x minutes to y:

10:45 = It's ten forty-five. = It's [a] quarter to eleven.
8:35 = It's eight thirty-five. = It's twenty-five minutes to nine.