The earliest tax-filing date changes each year based on when the Internal Revenue Service is ready to accept returns, but the date is typically in late January. The delay allows the IRS to accommodate end-of-year tax changes, according to Forbes. The 2015 tax filing season opened on Jan. 20.
The IRS usually allows taxpayers to start working on online returns before the tax filing season begins, but the IRS notes that it doesn't accept the forms until the opening date. Forbes advises taxpayers who are expecting a refund to have tax preparers complete their returns as soon as possible so that the forms are ready for filing when the season opens.