How Long Should an Ecommerce ERP Implementation Take?

Most vendors will give you a timeline. The more useful question is what that timeline assumes about your business, because the difference between a project that lands on schedule and one that drifts is usually not the software.

It helps to start with an outside reference point rather than a sales estimate.

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What the Research Says

Panorama Consulting's 2026 ERP Report, based on organisations surveyed between January 2025 and January 2026, puts the median project timeline at nine months. Almost a quarter of organisations reported their project ran over schedule.

That figure covers ERP projects across industries and sizes, including large manufacturers with complex requirements, so it is a ceiling rather than a forecast for a growing eCommerce brand. Retail-focused systems with pre-built channel integrations generally run shorter, because much of what a general ERP project spends its time building already exists.

The more instructive finding is the reason given for overruns. Delays were attributed mainly to organisational issues: governance, resistance to change and process redesign. Not the software, and not the technical work. The parts the buyer controls.

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The Phases

Most implementations run through the same sequence, whatever the system.

• Discovery and scoping. Mapping your order flow from checkout through to the ledger, and agreeing what the system needs to do. Time spent here reduces time lost later.
• Configuration. Setting up warehouses, channels, tax, price lists, fulfilment rules and user permissions to match how you actually operate.
• Data migration. Products, customers, suppliers, open orders, stock positions and historical transactions. Usually the phase that runs longest, and the time goes into cleaning rather than moving.
• Integrations. Connecting storefronts, marketplaces, carriers, 3PLs and the accounting ledger. Native connections are quicker than builds.
• Testing. Running real scenarios through the configured system, including the awkward ones: part shipments, refunds, backorders, trade accounts.
• Training. Warehouse, customer service, finance and purchasing each need a different version of this.
• Go-live and stabilisation. The first few weeks, when the exceptions surface and the rules get adjusted.

Two of these are worth planning around. Data migration takes as long as your data is messy, which means a product catalogue audit before the project starts buys you time. And testing is the phase most often compressed when earlier phases slip, which is exactly the wrong one to shorten.

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Why Timelines Slip

Sort the causes into those you control and those you do not.

Those you control and those usually yours:

• Decisions waiting on an answer. A configuration question sits unanswered for a fortnight because nobody is clear who decides. Naming one internal owner with the authority to make calls tends to do more for the timeline than any other single step.
• Data quality. Duplicate SKUs, inconsistent naming, missing supplier lead times and variants set up differently across channels all surface during migration. The work is the same no matter when you do it, but it is cheaper before the clock starts.
• Internal availability. The project needs real hours from people who already have jobs. A plan that assumes otherwise slips.
• Scope creep. The temptation to fix every process while you are in there. Worth resisting until after go-live, when you will understand the system better anyway.

Usually shared or the vendor's:

• Integrations that need building rather than connecting, which is why the integration question belongs in the evaluation. We covered that for Shopify in native integrations, connectors and middleware explained.
• Requirements that emerge during configuration because they were not surfaced during scoping.
• Consultant availability, particularly where the work is done by a third-party partner rather than the vendor's own team.

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Choosing a Go-Live Date

Work backwards from the dates you cannot move.

• Stay away from peak. Going live in October or November means your team is learning a new system during the highest volume weeks of the year, with no slack to absorb mistakes. Late spring and early summer are kinder.
• Avoid your financial year end, unless your accountant specifically wants a clean break there.
• Leave stabilisation room. Allow several weeks after go-live before anything else significant lands. Exceptions surface in the first fortnight and someone needs to be free to deal with them.
• Check who is on holiday. A four-week project phase with two of your three decision-makers away is a six-week phase.

If the only available window falls close to peak, it can be done. Cadet Direct went live roughly 90 days from go-ahead and now runs around 350 orders a day through a six-person warehouse team, having integrated warehouse management and shipping alongside the core system. But a date chosen for convenience and a date chosen because peak forced it are different risks, and worth naming as such internally.

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What to Ask About a Vendor's Timeline

• Is the timeline fixed or estimated, and what causes it to change?
• Who does the work, your own team or a partner, and what is their current availability?
• What do you need from us, in days per week, and from which roles?
• What happens if our data turns out to be worse than expected?
• What does the first month after go-live look like, and who is available during it?

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What a Shorter Implementation Depends On

Timelines compress when fewer things have to be built from scratch, and when the scope is agreed before the work starts rather than during it.

That is how Brightpearl by Sage is set up. Brightpearl is a Retail-First ERP System rather than a traditional ERP, built for retail from the start, so the channel, carrier and accounting connections that absorb months of a general ERP project are plug and play. Implementation is delivered by Brightpearl's own in-house team rather than an outside partner, and before you sign, you receive a Technical Solution Proposal setting out how the system will be configured for your workflows, along with a fixed cost quote, so you'll know exactly what to expect, avoiding any nasty surprises.

Brightpearl customers go live in 90 to 120 days on average, around 25% faster than legacy ERP projects, with a 97% implementation success rate.

What that has looked like for individual brands:

• Jeff Mills, Director at Baby & Co: "Taking less than 40 days to go live, which I was thrilled about. Having a dedicated Brightpearl team to implement and optimise the system made all the difference."
• Matt Wisniewski, COO at USA Lab: "Brightpearl managed the implementation for me in just three months and provided 1-2-1 training from a friendly expert."
• Jason McCarthy, MD at Wolverson Fitness: "Implementation was smooth and speedy, it took four months and was arranged to coincide with our move to a new warehouse."

Three different businesses, three timelines, each scoped and costed before the work began. That is the part worth asking any vendor to commit to.

Ready to plan an implementation around your calendar rather than ours?

Discover how Brightpearl scopes, configures and supports a go-live with its own implementation team. Book a demo today.

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