Ecommerce platform costs: a whole-life budget that separates cash, accounting and economic cost

An England merchant should budget for an ecommerce platform as an operating system rather than a website subscription. The whole-life total includes software, payment deductions and people. It also covers integrations, assurance and customer remedies. Migration, incidents and exit count as well.

A free core product or a plan with no monthly charge can still be the expensive route once those responsibilities are assigned.

This guide uses records opened on 6 September 2026. It gives no tax, legal or financial advice and promises no return. Where an input cannot be compared on the same basis, the field stays blank until an invoice, quotation or time record supplies it. The ranges below carry a typical label, never a quotation.

What to take away

Fix the merchant case first

Cost depends on the activity. Define the legal seller, goods and customer geography first. Then map the sales channels, payment flow, stock owner and fulfilment route.

The reference case here is one business established in England selling its own physical consumer goods to UK adults. It does not host third-party sellers, offer credit or sell regulated products.

That boundary prevents a misleading total. The FCA warns a marketplace or intermediary receiving customer money before passing it to a seller may provide payment services under its payment-services perimeter guidance.

HMRC's online marketplace VAT collection shows that route, seller establishment and goods location can alter tax analysis. A merchant outside the reference case needs a fresh map of the rules.

Record the planning horizon in months, the reporting currency as GBP, whether each input includes VAT, the expected order and transaction populations, and the present system retained as the baseline. Do not convert UK activity statistics into an England platform price.

A merchant doing 200 orders a month and one doing 20,000 do not share a bill. Volume drives payment fees, support hours and fulfilment cost more than the platform tier does.

Build a whole-life cost register

Platform and infrastructure

Enter the exact legal supplier, product and edition. Record the billing period, minimum commitment, renewal rule and cancellation route. Separate hosted subscription from web hosting, domain and storage. Traffic allowances, themes, extensions, app licences and development environments are separate lines too. A published zero only covers the supplier's stated unit.

Shopify's published UK tiers start at about £25 a month for the entry plan and climb past £300 a month for the top tier, before apps or transaction fees.

Self-hosted WooCommerce is free to download. A UK host typically costs £10 to £60 a month, and a .co.uk domain about £10 to £15 a year. Extensions commonly run at £60 to £300 a year each.

Shopify distinguishes subscription, card and third-party provider charges in its pricing overview. WooCommerce publishes server requirements for its free core software, leaving hosting, maintenance and extensions to the selected configuration. Those first-party statements show why unlike bundles should not share one headline cell.

Use this expression:

platform cost = subscription + hosting + domain + storage + extensions + integration licences + support plan

Every term needs a source date, VAT basis, unit and owner. A missing price is unknown, not GBP 0.

A small England store on a hosted plan with two paid apps, a theme licence and managed hosting commonly lands between £60 and £600 a month on platform alone. Catalogue size and traffic allowances drive the top of that range.

Payments, refunds and disputes

Map the payable event. Count successful online card payments separately from authorisations and failed attempts. Refunds, disputes and cash settlements get their own rows. Split UK cards, non-UK cards, alternative methods and currency conversion when the supplier does.

Stripe publishes standard UK card rates of about 1.5 per cent plus 20p a transaction, with higher rates for European and international cards. Square quotes about 1.75 per cent for standard UK card payments and around 2.5 per cent for keyed entries. PayPal's UK commercial rate sits near 2.9 per cent plus 30p.

Dispute fees typically land between £15 and £25 per chargeback, and the original processing fee is usually not returned.

The Shopify Payments refund record says the original card processing fee is not reimbursed when a merchant refunds a transaction. Square's UK refund guidance likewise says processing fees are not returned.

WooPayments states the same general rule and publishes separate country, international, conversion and dispute fields in its fee documentation. These are supplier conditions, not independent findings.

A payment row should therefore calculate:

payment cost = successful transaction fees + conversion additions + non-refunded fees on refunds + dispute charges + settlement charges

Use the merchant's event log and provider statement. Do not multiply a percentage by gross orders when some orders used another method or were never captured.

A shop taking £50,000 a month on UK cards at 1.5 per cent plus 20p across 2,000 orders pays roughly £750 in percentage fees and £400 in fixed fees. That is about £1,150 before disputes.

Customer remedies and fulfilment

Returns cost more than the customer refund. Include support handling, return carriage where applicable, inspection and restocking. Add loss of value decisions, replacement delivery, write-off and retained payment fees.

Handling a UK return typically costs £8 to £25 per order once carriage and inspection are counted, before any write-off. Personalised, hygiene and opened consumable lines often cannot be resold.

GOV.UK's returns and refunds page describes distance-selling cancellation periods, standard delivery refunds and exceptions. A qualified consumer lawyer must test the actual goods and journey.

For fulfilment, budget pick, pack, packaging and carrier labels. Add failed delivery, reshipment, storage, stock reconciliation and disposal.

Keep these amounts outside platform fees so a change in software does not appear to create a saving that came from a carrier or warehouse change.

Third-party pick-and-pack in England typically runs at £1.50 to £3.50 per order plus storage. A single reshipment after a failed delivery often adds the full outbound cost again.

People and implementation

Price work from observed hours or approved estimates by role. Include discovery, catalogue cleaning, product evidence, configuration and content. Add migration, integration, accessible design, testing and training. Finish with launch support and reconciliation.

The formula is deliberately blank:

internal labour = approved hours by role x approved loaded hourly rate

The loaded rate and treatment need the accountant and tax adviser. Contractors need their own scope, dependencies and VAT status. Set expenses, usage rights, correction duties and exit deliverables in the same schedule. No public salary survey proves this merchant's cost.

The National Living Wage for workers aged 21 and over was £12.21 an hour from April 2025. Employer National Insurance at 15 per cent above a £5,000 secondary threshold pushes a loaded hourly rate to roughly 1.2 to 1.35 times gross pay.

UK ecommerce contractors typically quote £350 to £700 a day. An agency day rate for the same work commonly starts higher.

Migration should have units: product records, variants, customer records and open orders. Count media files and integrations too. Add mapping, duplicate handling and rejected rows. Then reconciliation, archive and restore testing. Never budget only for the successful import.

Cart2Cart and LitExtension both price migrations per entity. A 5,000-product catalogue with customers and open orders costs materially more than a 200-product catalogue with none.

Assurance is not optional contingency

Maintain independent lines for product-safety evidence, consumer review and privacy analysis. Add PECR, accessibility testing and cyber-security assurance. Contract review, tax and accounting work sit alongside them. These gates cannot compensate for each other.

The ICO data protection fee is £40, £60 or £2,900 depending on size and turnover. Cyber Essentials certification typically costs £300 to £500, and Cyber Essentials Plus typically £1,500 to £3,000.

A WCAG 2.2 AA accessibility audit for a mid-size store typically runs from £2,500 to £12,000. Page count, checkout complexity and remediation rounds drive the range.

OPSS gives businesses current product-safety guidance, including distinct Great Britain and Northern Ireland considerations.

The ICO's controller-processor contract guidance identifies required contractual controls and carries a live review notice following the Data (Use and Access) Act.

NCSC's supplier assurance questions cover dependencies, offshoring, testing and recovery evidence.

None of those sources supplies a standard fee. Obtain scoped quotations or enter approved reviewer hours. Treat a missing assurance budget as an unresolved launch gate.

Operation, incidents and exit

Recurring work includes catalogue updates, account administration, security patches and integration monitoring. Add accessibility regression checks, payment reconciliation and customer support. Returns, complaints and corrections are recurring too. Define the unit for each, such as hours per accounting month or cases per reporting period.

Payment reconciliation alone commonly takes four to twelve hours a month. Platform support plans cost £30 to £200 a month where the supplier sells one.

Add an incident reserve through scenarios rather than an invented probability. Describe the event, response roles and forensic or legal support. Cover customer communication, restoration, reconciliation and lost operating time. Leave likelihood blank unless the merchant has a defensible evidence set.

Response work for a single serious incident, including forensics and legal support, typically starts around £5,000 and can pass £50,000 when customer data is involved.

Exit is a planned workstream. Include data export, media and licence checks, archive and deletion evidence. Add parallel running, DNS or domain work, supplier termination, account closure and restore rehearsal. A contract promising export does not prove that the exported catalogue, orders and payment evidence can operate elsewhere.

Most hosted contracts ask for 30 to 90 days' notice. A parallel run of one to three months is common before the old platform is switched off.

Separate cash, accounting and economic cost

One table can carry three views without blending them:

HMRC states that the standard VAT rate is 20 per cent for most goods and services on its VAT rates page, while the applicable rate depends on the supply. Do not simply add or remove VAT across every row. Record supplier treatment, merchant recovery assumptions and the tax adviser's decision.

A zero-rated line and a standard-rated accessory can sit in the same basket but not the same VAT row.

Make a budget that can be governed

For every line, store category, supplier or owner, currency and VAT basis. Add quantity, unit, period and source. Record access date, confidence and refresh trigger. Then add expected, low and high cells, without inventing probabilities that no evidence supports.

Set approval controls before selection:

Pause when a mandatory cost remains unknown or a quotation expires. Pause again when VAT treatment is unresolved, refund behaviour is untested, export cannot be restored or a risk gate fails.

Reforecast when volume, card geography or fulfilment route changes beyond the merchant's recorded tolerance. Reforecast again when the edition, integration set or customer remedy changes.

As an illustration, a small England merchant doing 2,000 orders a month on a hosted platform often lands between £1,500 and £8,000 a month in whole-life cost. Order volume, catalogue size, staffed hours and assurance gates drive the range.

Calculate return only after contribution

Observed orders show activity, not impact. Platform attribution assigns events under a rule, but it does not establish what would have happened without the change. Causal incrementality requires a credible comparison or counterfactual.

Use three separate lines:

observed net contribution = settled receipts - refunds - disputes - cost of goods - fulfilment - payment deductions - variable support cost

attributed contribution = observed net contribution assigned by the documented attribution rule

incremental contribution = measured contribution with the change - credible counterfactual contribution

Only the last belongs in an incremental return calculation, and uncertainty must travel with it. HM Treasury's Magenta Book is public-sector guidance, not a retail benchmark, but its distinction between observing an outcome and establishing attribution is a useful discipline. A measurement specialist should choose a proportionate design.

return ratio = (incremental contribution - full economic change cost) / full economic change cost

Leave the result blank when the denominator is incomplete or the counterfactual is not credible. A negative, uncertain or unevaluable result can support a hold decision.

Decision record before commitment

Approve a route only when the whole-life register has an owner for every row, material values share comparable units, supplier conditions are dated, and all specialist gates pass independently. Record why excluded routes failed, which assumptions remain, the sensitivity that could reverse the choice, and the next review date.

Publication also remains on hold until a named accountant, tax adviser, procurement lead and measurement specialist have reviewed the calculations. Qualified consumer, privacy and safety reviewers must sign off. So must accessibility, security and commercial reviewers. Reopen every price and supplier condition on the purchase date.

The goal is a budget that shows its missing evidence before the merchant commits.

Before you act

Common questions

Why can a free platform still be expensive?

A free core product or a plan with no monthly charge can still be the expensive route once responsibilities are assigned. The useful total includes software, payment deductions and people. It also covers integrations, assurance and customer remedies. Migration, incidents and exit matter too. Those costs need budgeting even when the subscription is zero.

How should payment costs be calculated?

Payment cost equals successful transaction fees plus conversion additions plus non-refunded fees on refunds plus dispute charges plus settlement charges. Use the merchant's event log and provider statement. Do not multiply a percentage by gross orders when some orders used another method or were never captured.

What should an exit plan include?

Exit is a planned workstream. Include data export, media and licence checks, archive, deletion evidence, parallel running, DNS or domain work, supplier termination, account closure and restore rehearsal. A contract promising export does not prove that the exported catalogue, orders and payment evidence can operate elsewhere.

What do the main cost lines typically look like in England?

Platform software typically runs £25 to £350 a month for a hosted tier, or £10 to £60 a month in hosting for self-hosted WooCommerce. Card fees commonly sit at 1.4 per cent to 3.25 per cent plus 20p to 30p an order. Assurance work ranges from £300 to £12,000 depending on scope.