Off-the-Shelf vs Custom ERP for UK Manufacturers: How to Decide

Walk round a typical 60-person manufacturer and the shop floor is often better equipped than the office. The machines are modern. The information that runs them is not: stock levels in one spreadsheet, the order book in another, customer history in a sales manager's inbox, and the accounts package as the only system everyone trusts. When someone asks whether an order can ship on Friday, three people check three places.

At some point the conversation turns to an ERP, and to the question this guide is about: buy a packaged system, or build one around how you work. We build custom software, so we have a view, but the honest answer is that both are right for some manufacturers and wrong for others. What follows is how to tell which you are, written for owner-led UK firms of roughly 20 to 250 staff.

What an ERP for manufacturing has to cover

ERP (enterprise resource planning) is a loose term. For a manufacturer, the test is whether one system holds the records that every department depends on, so a change made in one place shows up everywhere else. In practice that means six areas.

• Stock and locations: raw materials, work in progress and finished goods, by site, bin or van, with batch or serial numbers where customers or regulators need them.
• Bills of materials and routings: what goes into each product, in what quantities, through which operations, including revisions when a design changes.
• Production: works orders, scheduling against capacity, and the actual time and material booked against each job.
• Purchasing and suppliers: reorder points, purchase orders, supplier prices and lead times, and goods received against what was ordered.
• Sales and CRM: enquiries, quotes, orders, customer-specific pricing and the history of every account.
• Finance links: invoices, costs and stock valuation flowing into the accounts without being keyed in twice.

Not every firm needs all six on day one. A make-to-order fabricator lives and dies by quoting and job costing; a manufacturer selling standard products through distributors cares more about stock and replenishment. Knowing which two or three areas carry your business is the first step in deciding what to buy or build.

CRM for manufacturing: inside the ERP or alongside it?

Many manufacturers already have a CRM that the sales team half uses. The problem is rarely the CRM itself. It is that a salesperson cannot see stock, lead times or the status of an existing order without asking someone, so they stop trusting it and work from their inbox. Whether the CRM sits inside the ERP or is connected to it matters less than whether sales can see live operational data on the same screen as the customer record.

Where UK manufacturers are starting from

Make UK's 2025 report on digital adoption, published with Sage, found that while 70% of manufacturers are investing in digital tools, only 10% operate fully digital factories; 69% described themselves as partially digitalised, with some tools in place but gaps remaining.¹ In the same member surveys, 58% said ERP systems had a significant impact on their business, the highest of any technology listed.¹

The barriers in that report will be familiar. Nearly half of manufacturers (46%) named a lack of technical skills as their biggest hurdle, followed by integration difficulties caused by outdated IT infrastructure (41%), with workforce transitions and cultural resistance affecting 36%.¹

The Office for National Statistics paints a similar picture from a different angle. In its survey of UK firms with at least 10 employees, covering 2023, 61% had adopted specialised software, which the ONS defines as custom or packaged software for a particular business function, such as accounting, sales or inventory management, and which excludes spreadsheets.² Manufacturing firms led on specialised equipment, at 64%, against 31% in services.² That matches what we see: money goes into machines first and into the systems around them later.

The ONS also found technology adopters were associated with 19% higher turnover per worker than non-adopters, after controlling for management practices and firm characteristics.² That is an association rather than proof that software causes the difference, and the latest figures are for 2023, but it is a useful counter to the idea that systems are only an overhead.

When off-the-shelf ERP is the right call

Packaged ERP systems exist because most manufacturers share most of their processes. A good package has years of other firms' edge cases built in, a support team, regular updates and an ecosystem of consultants and add-ons. It tends to fit when:

• your processes are close to standard: buy, make, stock, sell, invoice, with no unusual steps that win you work;
• you are willing to change how you work to match the software, rather than the other way round;
• you want a vendor to own updates, security and compliance changes;
• the number of people who need access is modest, so per-user licences stay affordable;
• a product built for your sector already handles the things that matter to your customers, such as batch traceability or certificates of conformity.

The trap is customisation. Once a package has been heavily modified to fit an unusual process, every upgrade carries a risk of breaking it, and you can end up paying for a product and a custom build at the same time. If a shortlist only fits after extensive changes, take that as a sign to look at the other options.

When custom or hybrid makes more sense

A custom build makes sense when the way you operate is part of why customers choose you, and a package would force you to give that up or work around it in spreadsheets. Typical signs are complex product configuration, quoting that depends on your own cost models, assets that stay in the field after sale, or a mix of manufacturing, distribution and service that no single package handles well.

For many firms in the 20 to 250 range, the strongest option is a hybrid: keep the accounts package your finance team already knows, and build the operational core (stock, orders, production, CRM) around it, connected so nothing is keyed twice. This is also the simplest way to stay on the right side of HMRC. Making Tax Digital for VAT requires all VAT-registered businesses to keep records digitally and file returns using software, and HMRC's rules allow those records to sit across more than one product as long as they are digitally linked; copying and pasting between them does not count as a link.³ A custom core that feeds a compatible accounts package through a proper integration meets that test without you having to build tax filing yourself.

If you are weighing a build, our custom software page explains how we scope and deliver this kind of system in stages, and how to build systems that keep working as you grow covers the engineering choices that keep a custom build maintainable.

Total cost of ownership: what to put in the spreadsheet

The first-year price is the least useful number in an ERP decision. Compare options over five years, and make sure each line below is in both columns.

Per-user pricing deserves particular attention, because it shapes behaviour. If adding a user is expensive, firms limit access, and the people without a login go back to spreadsheets and messages.

On the other side, a custom build needs a realistic budget for support after go-live. Software that nobody maintains decays as the business changes around it. If you want to put a figure on what the current manual work costs before comparing, the manual work cost calculator gives you a baseline, and manual work versus automation ROI covers how to weigh it against the cost of a system.

The risks on each side, stated plainly

Off-the-shelf risks

• Bending your process to the software and losing something customers valued.
• Customisations that make upgrades slow and expensive.
• Licence costs that rise with headcount or with the modules you later find you need.
• Depending on a vendor's roadmap for features that matter to you.

Custom risks

• Depending on one developer or one small team; insist on owning the code, the data and the documentation.
• Scope creep, where every department adds requests and nothing goes live.
• No budget for support, so the system falls behind the business.

Risks that apply to both

The two that sink most projects are data and people. Product codes, BOMs and customer records built up over twenty years are rarely as clean as anyone thinks, and migrating bad data into a new system just moves the problem. And as the Make UK figures show, cultural resistance is as real a barrier as technology.¹ If the people who use the system every day are not involved in shaping it, they will route around it.

In practice: replacing disconnected systems at a UK manufacturer

The software cost saving came from replacing several separate tools with one system built around how the business actually works. That will not be true for every manufacturer: if your processes fit a package well, buying is likely to be cheaper. The point is to compare on your own processes and numbers rather than on a vendor's demo.

A phased approach to digital transformation in manufacturing

Whichever route you choose, a phased rollout carries far less risk than switching everything over one weekend. This is the order we would follow for most manufacturers.

Funding can help with the first steps. Made Smarter, the government-backed adoption programme for SME manufacturers in England, offers impartial advice, a digital roadmap and, in several regions including the West Midlands, match-funded grants of up to £20,000 for hardware and software, at the time of writing (October 2026).⁴ Support is for manufacturing or engineering firms with 249 employees or fewer, a turnover under £36 million or a balance sheet under £18 million, and the offer varies by region, so check what applies to you.⁵ Where judgement-heavy tasks remain after the core system is in, such as reading supplier documents or drafting quotes, AI agents can take on the first pass with a person checking the result.

Questions to ask before you sign anything

1. Which two or three processes carry our business, and does this option handle them without workarounds?
2. What does it cost over five years, including every user who needs access, not just the office team?
3. Who owns our data, and how do we get all of it out if we leave?
4. How does it connect to our accounts package, and does that link meet HMRC's digital link rules?
5. What happens to our changes when the product or the code is updated?
6. Who will clean and migrate the data, and how long has that been allowed for?
7. Can we go live in phases, starting with stock and orders?

Getting the systems right is half of growing a manufacturing business; the other half is winning the work they will handle. We cover that in marketing for manufacturers: what works in the UK.