Year-end tax document check

W-2 forms

• If your per diem was more than the federal rate, W-2 box 12 code L shows the non-taxed amount up to the federal rate, and the excess is in box 1. Per diem at or below the federal rate doesn't appear on the W-2. (Pub 463 (2025), ch. 6)
• From 2026, employers report qualified overtime on W-2 box 12, code TT. In January, compare your log with code TT. If code TT is low, ask for a W-2c.
• 2025: check whether you claimed the overtime deduction. If not, consider amending with Form 1040-X (generally within 3 years).

1099 income

• 1099-NEC/1099-K forms, plus your own income ledger
• For payments made in 2026, clients file a 1099-NEC at $2,000 or more. Report all 1099 income whether or not a form arrives.

Estimated tax (2026)

• Estimated-payment confirmations (IRS Direct Pay / Online Account)
• Last 2026 due date: Jan 15, 2027. You can skip it if you file your 2026 return by Jan 31, 2027 and pay in full.

Sources: IRS FS-2026-13; Pub 463 (2025), Table 6-1; Pub 334 (2025); Pub 505 (2026)