Tax
Estimated Tax Payments
Quick definition
Quarterly tax payments required for corporations expecting to owe $500+ in tax for the year. Due Apr 15, Jun 15, Sep 15, Dec 15.
C-corps that expect to owe $500+ in federal income tax must pay quarterly estimates: 25% of prior year's tax liability (or current year if larger), due on the 15th day of the 4th, 6th, 9th, and 12th month of the tax year. Underpayment penalties apply. Safe harbor: pay 100% of prior year's liability (110% if prior year AGI >$1M). S-corp passthrough income is paid via owner's individual quarterly estimates on Form 1040-ES.
Related tax terms
R&D Tax Credit
Federal credit for qualified research expenses, usable against payroll tax by startups.
Delaware Franchise Tax
Annual tax for Delaware corporations, often quoted wildly too high if calculated incorrectly.
Nexus (Sales Tax)
The connection with a state that triggers a tax-collection obligation.
QSBS (Qualified Small Business Stock)
Tax exemption for gains on qualifying startup stock held 5+ years.
See this in action
Insights and tools where Estimated Tax Payments shows up.
Frequently asked questions
- What is Estimated Tax Payments?
- C-corps that expect to owe $500+ in federal income tax must pay quarterly estimates: 25% of prior year's tax liability (or current year if larger), due on the 15th day of the 4th, 6th, 9th, and 12th month of the tax year. Underpayment penalties apply. Safe harbor: pay 100% of prior year's liability (110% if prior year AGI >$1M). S-corp passthrough income is paid via owner's individual quarterly estimates on Form 1040-ES.
- Why is Estimated Tax Payments important for startups?
- Estimated Tax Payments is a tax concept that matters for startup founders because it directly affects fundraising readiness, financial decision-making, or operational discipline at the stage where mistakes are expensive to undo. Founders who understand it have a meaningfully easier time in diligence, board meetings, and investor conversations.
- What category does Estimated Tax Payments belong to?
- Estimated Tax Payments is a Tax term in the StartupCFO finance glossary — alongside other tax concepts that founders, CFOs, and accountants use in daily startup operations and reporting.
- Where can I learn more about Estimated Tax Payments?
- Beyond this definition, see the related tax terms below, or explore StartupCFO's insights and tools that put Estimated Tax Payments in context. For specific situations, talk to a fractional CFO who can walk through your numbers.
Got a finance question that needs more than a definition?
Talk to a real CFO. 30 minutes, no contract, free.
