Your Derry firm books the sale in sterling on NetSuite, the invoice goes out in euro, and the margin vanishes in the gap
A custom ERP (Enterprise Resource Planning) for a Derry firm trading across the UK and Ireland border runs $70k to $160k over 4 to 8 months. You build it when off-the-shelf NetSuite, SAP or Odoo force one base currency and one tax regime onto a business that genuinely lives in two. For most North West tech and medical-device companies that means a dual-ledger core that holds sterling and euro at the line level, not a bolt-on currency module.
NetSuite, SAP and Odoo all assume a home currency and a home tax authority. In Derry that assumption breaks the first week. You sign a contract with a Letterkenny or Dublin customer priced in euro, your costs sit in pounds, and the platform either forces you to pick one base currency and absorb FX noise on every line, or it makes you run two company files that never reconcile cleanly.
The expensive version of this is the consolidation: month-end where finance exports both sets of figures into a spreadsheet, hand-keys the exchange rate they actually got from the bank rather than the platform's daily average, and the reported margin on a cross-border job swings four or five points depending on which rate won. Odoo's multi-currency is fine for occasional foreign invoices; it was never built for a company whose every other deal crosses a customs border.
Budgeting a erp build in Derry
| Project scope | Typical cost | Timeline |
|---|---|---|
| Dual-currency finance core + cross-border VAT | $70k to $110k | 4 to 6 months |
| Full ERP with inventory, traceability and reporting | $110k to $160k | 6 to 8 months |
| Phased: dual-ledger first, modules after | $45k to $75k initial | 3 to 4 months to first release |
The case for owning your erp
A custom ERP lets you hold both currencies as first-class citizens: every order, invoice and stock line carries its native currency and the settlement rate, so margin is calculated on what actually hit the account, not a platform average. It encodes your specific UK and Irish VAT logic, including reverse-charge on cross-border B2B, so finance stops patching it offline. For a North West firm whose competitive edge is winning work on both sides of the border, the ERP becomes the thing that makes dual-currency trading invisible instead of the thing that taxes it.
- More than a third of your revenue is cross-border GBP/EUR and FX noise is distorting your reported margin
- You run separate UK and ROI company files and spend days each month reconciling them
- You're in medical devices and need lot/UDI traceability your generic ERP can't express
- Custom pricing or contract structures that NetSuite or SAP can only model with heavy, expensive customisation
- You trade almost entirely in one currency and cross-border is occasional
- Your processes are standard enough that Odoo or NetSuite fit with light configuration
- You need to be live in under three months and can adapt your workflow to the tool
- You don't have anyone internally who can own a custom system after launch
What your build should include
ERP services we deliver in Derry
The engagements Derry teams bring us most often: Microsoft Dynamics 365, ERP migration, cloud ERP, manufacturing ERP and distribution ERP.
Delivery, week by week
Exactly what you get
You get an ERP where the border is a non-event. Orders, invoices and stock carry their native currency and the rate you actually settled at, VAT is computed correctly whether the customer is in Strabane or Sligo, and a single P&L rolls up your UK and ROI entities without a spreadsheet in sight. For device firms it adds the lot and UDI traceability your auditors expect. It connects to your accounting software, CRM (Customer Relationship Management) and inventory management software so the dual-currency truth is consistent everywhere it's read.
How to choose a developer in Derry
Pick a team that asks to see a real cross-border invoice before they quote, and that can explain UK and Irish VAT without reaching for Google. Local roots help here because the North West business community runs on trust and referrals, but proof matters more than postcode: ask for a multi-currency system they've shipped and the settlement-rate problem they solved on it. Be wary of anyone who treats dual currency as a checkbox rather than the core of the build.
- Line-level dual currency: every order holds GBP and EUR with the real settlement rate, so cross-border margin is finally accurate
- UK and Irish VAT logic encoded once, including reverse-charge on cross-border B2B, ending the month-end spreadsheet patch
- Single source of truth instead of two company files, cutting consolidation from two days to an afternoon
- Pricing and quoting tools that show the euro and sterling number side by side at the point of sale
- Connects cleanly to your accounting software, inventory management software and CRM so the dual-currency truth flows everywhere
- You take on responsibility for keeping UK and Irish VAT rules current as HMRC and Revenue change them, work a SaaS vendor would otherwise do
- A dual-ledger core is genuinely harder to build and test than a single-currency ERP, so the bottom of the cost range is rarely realistic
- You lose the large NetSuite and SAP partner ecosystem for plugins, reporting packs and certified consultants
- Audit and statutory filing integrations you'd get free in QuickBooks or Xero now have to be built or wired in
- !They quote a fixed price before seeing how your cross-border invoicing actually works. Ask them to walk through a euro-priced, sterling-costed job first
- !They've never built multi-currency at the line level and propose a single base currency. Ask how they capture the real settlement rate
- !No question about UK versus Irish VAT. Ask them to explain reverse-charge on a cross-border B2B sale
- !They want to replace everything at once. Ask for a phased plan that ships the dual-ledger core first
- !They have no answer for medical-device traceability. Ask how lot and UDI data will be enforced
Most Derry teams pricing erp end up comparing notes on internal tools, shopify, inventory management too; the systems share one data spine.
Rohan advises mid-market and enterprise teams on ERP, CRM and custom software, and has led delivery on dozens of business-software builds.
Writes for Digital Heroes, shipping business software for 2,000+ brands across 55+ countries since 2017.
Frequently asked questions
Can't NetSuite or Odoo just handle multiple currencies?
They handle foreign invoices, but they assume one base currency and apply a daily average rate. For a Derry firm where half the deals are euro-priced and sterling-costed, that average distorts margin on every cross-border job. A custom build holds both currencies at line level with the real settlement rate.
How does a custom ERP handle UK and Irish VAT together?
It encodes both rule sets once: GB domestic VAT, ROI domestic VAT, and reverse-charge on cross-border B2B. The system picks the right treatment per transaction and produces filing-ready outputs for both HMRC and Revenue, so finance stops patching it in spreadsheets.
What does an ERP build cost for a Derry SME?
A dual-currency finance core starts around $70k to $110k over 4 to 6 months. A full ERP with inventory, traceability and consolidated reporting runs $110k to $160k over 6 to 8 months. Phasing the dual-ledger first lets you start nearer $45k.
Should we keep our accounting software or replace it?
Many Derry firms keep Xero or QuickBooks for statutory filing and build the ERP around them, with the dual-currency truth flowing into accounting via integration. If your filing needs are simple, folding accounting into the ERP can reduce reconciliation, but it adds build scope.
How long before we see value?
With a phased approach the dual-ledger core can be live in three to four months, killing the month-end consolidation spreadsheet first. Inventory, traceability and consolidated reporting follow in later releases.