If you have a tax liability of more than $50,000 in the look back period (2012Q3 + 2012Q4 + 2013Q1 + 2013Q2), the semi-weekly deposit schedule applies to you. As a semi-weekly schedule depositor, your deposit of accumulated taxes for wages paid on Wednesday, Thursday, or Friday is due by the following Wednesday. Deposit of accumulated taxes for wages paid on Saturday, Sunday, Monday, or Tuesday, is due by the following Friday.

Additionally, if your accumulated 941 tax liability reaches $100,000 or more at any time during a semi-weekly period, your electronic deposit is due by the next business day. This is known as the $100,00 Next-Day Deposit Rule.

These rules do not apply to federal unemployment FUTA 940 type payments, as different deposit requirements apply to FUTA tax.

Source Internal Revenue Service CP-136 “Your 2014 Federal Tax Deposit Requirements for 941”