The length of time it would take to count to a billion depends on how fast an individual counts. At a rate of one number per second, it would take approximately 31 years, 251 days, 7 hours, 46 minutes and 40 seconds of counting nonstop.

In the United States, the term "billion" is denoted by the number 1 followed by 9 zeros, or 1,000,000,000. The estimated time it would take to count without pause from one to one billion is taken by initially dividing one billion seconds by 60 to get the number of minutes. The result is further divided by 60 to obtain the number of hours and then divided by 24 to get the number of days. To obtain the number of years, the result is again divided by 365.25, with the decimal part accounting for leap years.