Routine costs
Hosting, domain registration, SSL certificates, content management subscriptions (WordPress.com, Squarespace, Shopify), small content updates, and routine maintenance are current-year deductible expenses.
Large redesigns
A complete website rebuild that creates a long-lived asset (graphic design assets, custom code, e-commerce architecture) may need to be capitalized and depreciated over 3 years (off-the-shelf software) or amortized over 15 years (Section 197 intangibles, including websites in some interpretations). Section 179 or bonus depreciation can usually fully expense it in year one anyway.
Internal vs external development
Costs paid to external developers are easier to characterize and deduct or capitalize. Internal labor costs (your own time, employee time) generally cannot be capitalized — internal labor that produces software is currently deductible under Section 174 with capitalization required for software development costs since 2022.
Section 174 R&E capitalization
Beginning in 2022, software development costs and other research-and-experimental expenditures must be capitalized and amortized — 5 years for domestic R&E, 15 years for foreign R&E. Many small-business website costs do not rise to "software development," but custom-built e-commerce platforms might.
Where it goes
Schedule C line 8 ("Advertising") or line 22 ("Supplies") for hosting and routine costs. Capitalized development goes on Form 4562 and amortizes over the appropriate period.
Worked example with numbers
Consider a sole prop with $100,000 in gross receipts and $30,000 in legitimate Schedule C deductions, including this category. Each additional $1,000 of qualifying expense reduces Schedule C net profit by $1,000, which reduces self-employment tax by approximately $1,000 × 92.35% × 15.3% ≈ $141, and reduces income tax by $1,000 × marginal rate. At a 22% federal marginal rate, the combined federal tax savings on each additional $1,000 of legitimate deduction is roughly $361, and state savings sit on top of that. The math is why disciplined categorization throughout the year pays for itself.
Common mistakes that disallow the deduction
The recurring ways this deduction gets disallowed in examination cluster in four categories: (1) personal-use expenses bundled with business (the deduction is disallowed entirely or apportioned downward); (2) inadequate substantiation (no receipt, no invoice, no business-purpose note); (3) the wrong line on Schedule C (not fatal, but it weakens audit defense); and (4) double-counting with another line (for example, deducting an expense on Schedule C and also on Form 8829, or as a personal itemized deduction on Schedule A). The fix in every case is contemporaneous bookkeeping and a clean chart of accounts.