Deadlines for Tax Year 2018 (due in early 2019)
 
If you file forms To the IRS on paper To the IRS electronically Mail to the recipient by
W-2 January 31 January 31 January 31
W-2G Febuary 28 March 31 January 31
1042-S March 15 March 15 March 15
1094-1095 Febuary 28 March 31 January 31 March 2, 2019
1097 Febuary 28 March 31 March 31
1098 Febuary 28 March 31 January 31
1099 Febuary 28 March 31 January 31
1099-Misc (NEC only) January 31 January 31 * January 31
3921 Febuary 28 March 31 January 31
3922 Febuary 28 March 31 January 31
5498 May 31 May 31 January 31-for FMV/RMD May 31-for contributions
8027 Febuary 28 March 31 Unknown

Late Filing Penalties

Note: If any due date falls on a Saturday, Sunday, or legal holiday, the return or statement is considered timely or furnished on the next buisness day.

Forms W-2, W-3, must be filed to the IRS and provided to employees by January 31, NO EXTENSIONS allowed.

*
However, the e-Filing date for 1099 Misc NEC can be extended to the end of February.
1099 Misc-NEC must be filed to the IRS and provided to payees by January 31, NO EXTENSIONS allowed. A new rule as of August 2018.

Form 1099-Misc-NEC means 1099-Misc with Money in Box 7, Non-Employee Compensation.

Forms 1099-Misc-NEC (money in Box 7) must never be submitted to the IRS late with other Form 1099-Misc (money in other boxes).
If so, the IRS will penalize you for ALL FORMS in the FILE.

The due date to the IRS for Form 1099-MISC with NO data in box 7, or other 1099 forms, remains at Febuary 28(paper) and March 31(Electronic) .

For more detailed information on Deadlines and Late Filing Penalties see the 1099 General Instructions