Start with the development scope
Use an agreed proposal for the build. Add content production, translations, photography and migration if they are not included. The SiteCost development estimate deliberately excludes these items; its total should not be mistaken for an all-in operating budget.
Check renewals and billing periods
A domain’s renewal price can differ from its introductory offer. Platform costs also depend on billing frequency, features and usage. Compare the charge for your actual billing period and planned functionality.
Check current figures directly on Shopify’s pricing page or Webflow’s pricing page when considering those platforms. A self-hosted WordPress installation also needs a compatible hosting environment; see the WordPress hosting requirements. These references do not supply a development quote.
Account for usage and responsibility
Payment processing, email delivery, AI features and other services may charge by usage. Build separate volume scenarios using the provider’s terms. The planner’s “other annual costs” field can hold your estimated annual amount; it does not calculate transaction fees automatically.
Ask who handles software updates, backups, monitoring and support requests. Name the included tasks and response expectations. A maintenance allowance is only meaningful when someone has agreed what it covers.
Do not treat unknowns as zero
The planner shows a subtotal of what you entered. Blank fields remain unknown. Even with every field completed, review taxes, renewal timing and variable fees against the actual providers and agreements.
For a build estimate, choose a website cost guide. For an explanation of the development assumptions, read the SiteCost methodology.