A useful tax calendar connects each deadline to a business, a tax period and a person responsible. This calendar was reviewed in September 2026 and covers common US federal dates for calendar-year taxpayers. Fiscal years, special relief, state taxes and individual circumstances can change what applies.
Common annual return dates in 2026
- March 16: ordinary deadline for 2025 calendar-year partnership and S corporation returns.
- April 15: ordinary deadline for 2025 individual returns and calendar-year C corporation returns.
- September 15: extended deadline for those partnership and S corporation returns with valid extensions.
- October 15: extended deadline for those individual and calendar-year C corporation returns with valid extensions.
These dates reflect the IRS 2026 tax calendar. An extension generally does not extend payment time. At this September review, the first three dates have passed; keep the October deadline on your action list if it applies.
Estimated payments for 2026 individual income
The ordinary installment dates for calendar-year individuals making 2026 estimated payments are April 15, June 15 and September 15, 2026, followed by January 15, 2027. See Publication 505 for applicability, calculation methods and exceptions. Corporation estimated-payment rules differ.
Do not label the January payment as a 2027 income-tax installment: it generally relates to the final payment period for 2026. Save the payment confirmation with the correct tax year.
Add the dates this overview cannot determine
Payroll deposits, employment returns, information returns, state income taxes and sales tax can add separate obligations. Your location, workforce, transactions and assigned filing frequency matter. Use the IRS online tax calendar and the relevant state agencies to build the full list.
Record the source and review date for each obligation. When the business hires in a new state, changes structure or begins a new activity, ask whether the calendar needs updating.
Use a five-field calendar entry
For each item, record the entity, form or obligation, tax period, official due date and owner. Add a link to the payment or filing portal and a separate internal preparation date. This makes it harder to confuse a payment with a return or one company's obligation with another's.
Set a preparation reminder far enough ahead for missing documents and questions. A deadline reminder on the due date is too late if the books still need reconciliation.
Prepare the evidence continuously
Collect supplier invoices and receipts during the year. Receiptor AI's automatic extraction helps gather emailed documents, with WhatsApp and iMessage submission routes for other receipts. Historical extraction helps recover older messages when preparation reveals a gap.
Review legal entities, duplicates and related documents before accounting export. Receiptor's Xero and QuickBooks integrations connect evidence to bills, expenses and payments; the filing owner still confirms the tax treatment and completes the return.
Close each deadline with proof
Mark an obligation complete only after checking acceptance or payment confirmation. Preserve the confirmation and note any follow-up required. At the next monthly review, look for overdue items and check upcoming dates against the current official guidance.
