1. Vehicle mileage
Standard mileage method. Multiply business miles by the IRS rate. 2025: 70¢/mile · 2026: 72.5¢/mile.
2. Home office (simplified method)
$5 per square foot of business-use space, capped at 300 sq ft = $1,500 maximum. Same rate for 2025 and 2026. Space must be regularly AND exclusively used for the business.
3. Cell phone & internet
Deductible at your business-use percentage. Be honest — the IRS expects a reasonable, documentable allocation.
4. S-Corp health insurance
As a more-than-2% S-Corp shareholder, premiums the corp pays on your behalf (and reports in your W-2 Box 1) are deductible above the line on your 1040 — full amount, no AGI floor. Structural rule; no rate change between years.
5. Retirement contributions (SEP-IRA / Solo 401(k))
Conservative SEP-IRA / Solo 401(k) employer-side estimate: 25% of W-2 wages from the S-Corp, capped at the annual IRS limit. 2025 cap: $70,000 · 2026 cap: $72,000. Excludes employee-deferral elections and age-50+ catch-up.
6. Business meals
50% of qualifying business meals are deductible (post-2022; the 100% COVID-era allowance expired). Same 50% rate for 2025 and 2026. Meal must have a business purpose and be substantiated.
Your estimated annual picture
Combined deduction across all six categories — and what that could mean in tax savings at three common federal brackets. (Federal-only; doesn't include state or payroll-tax interactions.)
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Estimates only. Not tax or legal advice. This calculator uses standard IRS rates as published; your actual deductible amounts depend on facts I don't have here — substantiation, allocation methods, basis limitations, AGI thresholds, state rules, and the rest. Verify against current IRS guidance for your situation, or have a CPA confirm before you act.
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