Tax deadlines: build a reliable filing calendar
A reliable filing calendar depends on entity type, tax year, state and elections—not a single universal date.
Quarterly estimates
Individuals with estimated tax obligations often use April, June, September and January due dates, adjusted for weekends and holidays.
Annual returns
Federal deadlines differ across individuals, partnerships and corporations. Extensions generally extend time to file, not time to pay.
Track approvals
Keep preparation, client authorization, CPA review, submission and IRS acknowledgement as separate milestones.
Avoid surprises
Confirm your exact due dates and extension eligibility with a qualified US tax professional.
General educational information only. Not legal, accounting or tax advice. Consult a qualified US professional for your circumstances.
A concrete planning example
Suppose a small company changes its ownership structure midway through the year while earning revenue in two states. The tax filing checklist cannot be built from revenue alone: ownership, federal classification, physical operations, payroll and any elections can each change the answer. Write down the dates of each change, gather supporting documents and ask the tax preparer which federal and state returns apply. Do not assume that an LLC label determines its federal tax treatment.
A step-by-step review process
Start by identifying the reporting period and the specific decision you need to make about tax deadlines: build a reliable filing calendar. Collect the underlying statements, invoices, contracts and any prior-period workpapers. Compare source records to the amounts in the ledger, and make a separate list of exceptions rather than changing figures to force a match. Ask who owns each unresolved item and set a target date for completion. After corrections, save a dated review summary so the next monthly close starts from a reliable baseline.
What to document
For tax deadlines: build a reliable filing calendar, keep the date of the review, the person who prepared it, the evidence used, the questions that remain open and any decisions made by your CPA or bookkeeper. Attach supporting statements or receipts to the relevant transactions when possible. If an estimate or assumption was necessary, label it clearly and revisit it when better information becomes available. This record can reduce repeated questions at year-end.
Mistakes to avoid
Avoid relying on a bank balance as a substitute for complete books. Do not mix personal and business transactions without documenting the business purpose. Do not delete unexplained entries just to make a report look cleaner. Do not assume that a prior-year filing position or a generic online deadline applies unchanged this year. Escalate material differences, unusual transactions and potential filing requirements to a qualified professional.
Questions to ask your bookkeeper or CPA
Which parts of tax deadlines: build a reliable filing calendar depend on my accounting method, entity classification or state? Which documents are still missing? What exceptions could materially affect the financial statements or a return? Who will approve adjustments, and when should we review them again? Which decisions should be documented in writing? These questions help turn a general guide into a repeatable monthly or annual workflow.
Practical checklist
Before marking this work complete, confirm that source records cover the full period, outstanding items have owners, corrections have supporting explanations, reports are internally consistent and important deadlines are tracked. Keep a copy of the final report and related evidence in an organized location with restricted access. A clean process matters more than an impressive dashboard: it should be possible to trace each important number back to its source.