Why this matters
The moment you file this year's return is the moment to lock in next year's payment dates. Miss a quarterly deadline and the IRS charges an underpayment penalty that accrues until you pay, even if you end up due a refund at filing.
What "done" looks like
- Four calendar entries with reminders a week before each due date
- An amount attached to each date, from TurboTax's 1040-ES vouchers or safe-harbor math
- A funding plan — which account the money comes from
- State estimated dates added too, if your state requires them
How to do it
- Calendar the federal dates now: April 15, June 15, September 15, and January 15 of the following year (next business day if a weekend or holiday).
- Save the 1040-ES vouchers TurboTax can generate from this year's numbers.
- Use the safe harbor if income is unpredictable: pay 100% of last year's tax (110% if AGI topped $150,000) and no penalty applies regardless of earnings.
- Set up IRS Online Account or EFTPS so each payment takes two minutes.
- Automate the funding — move a fixed percentage of every deposit into a tax sub-account so the cash exists when the date hits.
Common mistakes
- Assuming the payments are evenly spaced quarters — June 15 surprises everyone the first year
- Forgetting the January date because it lands in a new calendar year
- Calendaring the dates but never deciding where the money comes from
Real-world examples
- The IRS schedule is genuinely uneven: the four "quarters" are 3, 2, 3, and 4 months long, which is why the June deadline is the most commonly missed.
- TurboTax can prepare next year's Form 1040-ES vouchers automatically from this year's return — a documented feature most filers click past.
From a founder's point of view
Quarterly taxes are the first recurring obligation where nobody invoices you — no bill arrives, and the penalty accrues silently. Treating the four dates like payroll, with cash set aside in advance, turns a dreaded scramble into a non-event.
Rule of thumb
If the four dates aren't on your calendar with amounts and a funding source by the time you file this year's return, you haven't finished filing.