EN ES

eCommerce Website Cost Calculator

Estimate the full cost of an online store: the build, the monthly fees and the payment costs that grow with sales.

Updated 3 October 2026

Quotes for a new online store usually focus on the build. Over a few years, monthly fees and payment processing often cost as much or more. This calculator puts all three in one place.

One-off costs
Monthly fixed costs
Sales and payment fees
One-off build costs
–
Fixed running costs per year
–
Orders per year
–
Payment processing per year
–
Platform transaction fees per year
–
Total running costs per year
–
First-year total
–
Total over 3 years
–
Total as share of online revenue
–

Pre-filled numbers are only an example to show how the calculator works; replace them with your own quotes. Amounts are in whatever currency you use. Everything is calculated in your browser and nothing is sent anywhere.

What goes into the cost of an online store

One-off costs

  • Design: research, UX, page templates and a component library. A premium theme reduces this; a bespoke design increases it.
  • Development and setup: theme customisation or custom front end, configuration of products, shipping, taxes and payments, and custom features.
  • Integrations: ERP, inventory, shipping, CRM and marketing tools. Ready-made connectors cost less than custom integration work.
  • Content: product photography, descriptions, translations and legal pages.
  • Migration: moving products, customers, orders and URLs from an old store, including SEO redirects. See the replatforming checklist.

Recurring fixed costs

  • Platform plan or licence: SaaS subscription (Shopify, BigCommerce), or licence for enterprise software. Open-source platforms have no licence fee.
  • Hosting: included in SaaS plans; separate for WooCommerce, Magento Open Source and custom builds.
  • Apps and extensions: reviews, search, subscriptions, loyalty, email and so on, often billed monthly.
  • Maintenance: updates, security patches, bug fixes and small improvements.

Costs that grow with sales

  • Payment processing: usually a percentage of each payment plus a fixed amount per transaction. Rates vary by provider, country, card type and volume; check your provider's current price list.
  • Platform transaction fees: some platforms add a fee per order, for example Shopify when you use a third-party payment gateway instead of Shopify Payments, and some enterprise licences are priced by revenue.

How to use the result

  • Run the calculator once for each option you are considering (for example hosted platform vs custom build) and compare the multi-year totals rather than the launch price.
  • Check how the total moves when revenue doubles: percentage-based fees grow with sales, fixed costs do not.
  • Leave a contingency (often 10–20 %) for scope changes that appear once work starts.
  • Do not forget marketing: the store needs traffic, and that budget is separate.

Want a quote based on your requirements? Send us your scope and we will reply with questions and an estimate.

Frequently Asked Questions

How much does it cost to build an eCommerce website?

It ranges from little more than a monthly platform fee for a simple theme-based store set up by the owner, to six-figure budgets for custom or headless builds with many integrations. The main drivers are custom features, design depth, number of integrations and data migration.

What are the ongoing costs of an online store?

Platform or hosting fees, apps and extensions, maintenance, payment processing and, on some platforms, transaction fees. Marketing comes on top.

Is a custom eCommerce site cheaper in the long run?

Sometimes. Removing licence and revenue-based fees can offset a higher build cost at higher sales volumes, but custom stores need ongoing development budget. Compare both options over three to five years with the calculator above.

Need help applying this to your store?

Tell us about your platform, systems and goals and we will reply by email.

Contact Us