Quarterly Estimated Tax Calculator for Airbnb Hosts — STR Self-Employed Tax Spreadsheet — Excel + Google Sheets

Stop guessing what you owe in April, June, September, January. Quarterly estimated tax calculator for Airbnb and STR hosts. Avoid the IRS underpayment penalty. Editable Excel.

You got hit with a $400 underpayment penalty last April. The IRS doesn't care that
your STR income was lumpy — they care that you didn't pay enough as you went. The
fix is the quarterly schedule: April 15, June 15, September 15, January 15. Pay
roughly 25% of your projected annual tax each quarter, and the penalty goes away.

The hard part is "roughly." This workbook does the math.

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WHAT'S INCLUDED
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📋 Annual Income Forecast
· Project STR income from current YTD + seasonal pattern
· Account for spouse W-2 withholding (joint filers)
· Other 1099 / side-gig income line
· Auto-recommended Safe Harbor (110% of last year's tax)

📋 Quarterly Schedule (4 quarters × line items)
· Q1 due April 15, Q2 due June 15, Q3 due September 15, Q4 due January 15
· Income tax + SE tax + state estimate per quarter
· Already-paid column (deduct what you've sent in)
· "What to send" cell — bottom-line dollar amount per quarter

📋 SE Tax Worksheet
· Schedule E filers: typically $0 (rental income is not SE)
· Schedule C filers: 15.3% × 92.35% × net SE earnings
· Auto-routes based on your filing classification

📋 Safe-Harbor Check
· 100% prior-year (under $150K AGI) or 110% (over $150K)
· 90% current-year as alternative
· Whichever is lower — that's your safe harbor target

📋 IRS Form 1040-ES Quick-Reference
· Voucher line numbers, payment URL
· IRS Direct Pay link (no fees)
· State estimated-tax pointers

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WHY STR HOSTS NEED THIS
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Airbnb doesn't withhold tax. Vrbo doesn't withhold tax. Stripe doesn't
withhold tax. Direct-booking deposits don't withhold tax. If your only
withholding is a spouse's W-2 (or zero, if you're self-employed full-time),
the IRS expects you to send them quarterly checks.

Miss enough of those, and you owe Form 2210 underpayment-penalty interest
on top of your tax bill in April. Penalty rates float with the federal
short-term rate — currently about 8% annualized. On a $20K shortfall over
the year that's $1,600 you didn't need to pay.

This workbook is the schedule that prevents it.

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WHO THIS IS FOR
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· Airbnb / VRBO hosts with no W-2 withholding (or insufficient withholding)
· Hosts who got hit with an underpayment penalty last year
· Multi-property operators projecting a profitable year
· Schedule C filers facing 15.3% SE tax on top of income tax
· DIY filers who file estimateds in TurboTax but want to forecast first

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HOW IT WORKS
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1. Open in January (or any time during the year — the calculator handles partial years).
2. Paste your prior-year tax (from last year's Form 1040 line 24) into Settings.
3. Project current-year income on the Forecast tab.
4. Open the Quarterly Schedule — the workbook tells you what to send Q1, Q2, Q3, Q4.
5. Pay via IRS Direct Pay (free) or your CPA's portal. Mark paid in column F.
6. Re-run after each quarter to recalibrate.

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FILE COMPATIBILITY
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✅ Microsoft Excel 2016+ (Windows and Mac)
✅ Microsoft Excel 365
✅ Google Sheets

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REFUNDS + SUPPORT
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14-day refund, no questions asked. Email hello [!at] thestrledger.com — real humans,
fast replies.

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ABOUT THE STR LEDGER
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Business-grade Excel systems for serious short-term rental hosts.
Full template library at thestrledger.com.

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⚠ Digital product. Not tax advice. Consult your CPA for your specific situation.
IRS Form 1040-ES (Estimated Tax for Individuals) is the canonical reference.