For general informational purposes only — not tax, legal, or financial advice. Consult a qualified professional before acting on these estimates. NRM Business Advisory, LLC assumes no liability for outcomes.
NRM Business Advisory, LLC

Quarterly Estimated Tax Calculator

Plan federal and California quarterly payments and stay clear of underpayment penalties
Your numbers
Tax year
2025
2026
Filing status
Married filing jointly
Single / HOH
Expected self-employment income $150,000
Expected W-2 wages (if any) $0
Federal tax already withheld this year $0
Safe harbor — prior year
Prior year total federal tax $25,000
Prior year AGI $180,000
Used to determine whether you owe 100% or 110% of last year's tax under the safe harbor rule.
🐻 California
Include California estimates
Prior year CA tax $9,000
CA tax already withheld this year $0
CA uses the same prior-year AGI figure above to determine its 100%/110% threshold, and drops the prior-year safe harbor entirely above $1M AGI ($500k MFS).
Required annual payment
$0 combined
Federal: $0
California: $0
Federal quarterly payments — equal 25% installments
California quarterly payments — front-loaded 30/40/0/30
Heads up: California does not split estimated payments evenly like the IRS. FTB Form 540-ES requires 30% in Q1, 40% in Q2, 0% in Q3, and the remaining 30% in Q4 — applying the federal 25% split to California is one of the most common causes of FTB underpayment penalties.
How this was calculated
Expected current-year tax
Federal income tax$0
Self-employment tax$0
Total federal tax$0
California tax$0
Safe harbor comparison — federal
90% of this year's tax$0
100% of prior year's tax$0
Less: withholding already paid$0
Less: CA withholding already paid$0