By default, the crontab uses OR when the day of the week and day of the month are specified.
For, example, 7 0 12 * Fri will run your cronjob at 00:07 on Friday OR on day 12 of each month.

It would be impossible to require matching of both the day of the week and the day of the month using either crontab syntax or time expression.
For example, run cronjobs on Friday the 12th, or run on Tuesday and Wednesday from day 10 to day 20.
To solve this, FastCron now supports the Time filter.
To show the Time filter, click on the Filter button.
It supports simple expressions with 5 variables:
minute: integer, from 0 to 59hour: integer, from 0 to 23day: integer, from 1 to 31month: integer, from 1 to 12weekday: string, including Mon, Tue, Wed, Thu, Fri, Sat, and SunIt supports a lot of operators. See the full list here.
Here are some examples for you:
1 day 8:00 (or 0 8 * * *) and the filter to day == 12 and weekday == 'Fri'(weekday == 'Tue' or weekday == 'Wed') and day >= 10 and day <= 20 or weekday in ['Tue', 'Wed'] and day >= 10 and day <= 20This feature is available in all premium plans.
Need help? Reach out to support@fastcron.com - we're happy to help.
See why 8,000+ website developers and their teams use FastCron to run their cronjobs 12 million times a day.
The reliable online cronjob service for your websites since 2009.