If you are collecting quotes for a custom ERP, you have probably seen figures ranging from 3,000 to over 100,000 EUR, with little explanation of why. The short answer: a custom module on top of your current ERP costs between 1,500 and 8,000 EUR, and a full custom ERP starts at 15,000 EUR. The honest answer: most SMEs do not need the latter.
How much does a custom ERP cost in 2026?
In 2026, the cost of a custom ERP in Spain falls into three clear brackets. A custom module built on top of an existing ERP such as Sage, Holded, Odoo or A3 costs between 1,500 and 8,000 EUR. An integration between your ERP and other systems, email, CRM or online store, runs between 1,500 and 4,000 EUR. A full ERP built from scratch starts at 15,000 EUR and can easily exceed 40,000 EUR depending on scope.
The price difference does not come from the number of screens. It comes from three factors: how many processes the system covers, how many other tools it connects to and how many users work in it at the same time. Be wary of hourly quotes. At ASD Solutions we fix the price before starting: if a module costs 4,000 EUR, it costs 4,000 EUR even if development gets complicated. The estimation risk is ours, not yours.
Do you really need a full custom ERP?
In most cases, no. We say this even though we sell custom development: of every ten SMEs that ask us to quote their own ERP, around eight are better off extending the one they already run. Sage, Holded, Odoo and A3 handle accounting, invoicing and purchasing well. Where they fall short is the specific 20 per cent of your business: your factory's cost breakdowns, your fleet's routes or your warehouse's shipping rules.
That gap is covered with two tools far cheaper than a new ERP: custom modules that build on your current data, and custom ERP and CRM integration so your systems talk to each other. Replacing your ERP because it lacks one feature is like moving house because a socket is missing. Before signing a 30,000 EUR project, check whether a 4,000 EUR module solves the problem.
How much does a custom module on your current ERP cost?
Between 1,500 and 8,000 EUR, delivered in 3 to 6 weeks in most cases. These are specific pieces your ERP does not ship with: a portal where your customers check orders and download delivery notes, a warehouse app for picking with barcode scanners, or digital work orders that push shop-floor hours straight into the system. The module lives outside the ERP and talks to it through its API, so vendor updates do not break it.
A real example by sector: a distribution company with around 30 employees was manually keying into its ERP the orders arriving by email, roughly 2 hours a day of one person's time. A module that reads those emails and creates the orders automatically cost under 4,000 EUR and paid for itself in about 5 months. Nobody had to touch the ERP or migrate a single record.
How much does it cost to integrate your ERP with other systems?
Typical email, ERP and CRM integrations cost between 1,500 and 4,000 EUR. That is the usual range for connecting Sage or Holded to a CRM, syncing stock with an online store or automating delivery note entry. Our custom ERP and CRM integration service includes the upfront analysis, the development, testing with real data and one month of support after delivery, all under a fixed price agreed in writing.
Before choosing between extending your ERP or replacing it, compare the full numbers: licences, migration, training and 5 years of maintenance. We have published a comparison of custom ERP versus SaaS with that detailed calculation. The short version: below 15 users, SaaS extended with modules almost always wins; from 30 users with unusual processes, the balance starts to shift.
When is a full custom ERP worth it?
A full custom ERP, from 15,000 EUR and taking 2 to 4 months, makes sense in three specific situations. First: your core process is your competitive edge and no standard ERP fits it without heavy workarounds. Second: you pay per-user licences and with 40 or more employees the annual fee exceeds what amortising your own build over 3 or 4 years would cost. Third: you depend on an unsupported legacy system and migrating to a standard package would force you to rebuild every process anyway.
And when it is not worth it: if the pain sits in a single department, if you have fewer than 10 users, or if your current ERP works and only lacks a few pieces. In those cases, a sensible investment range for an SME sits between 1,500 and 15,000 EUR, not above. Anyone proposing to start from scratch without auditing what you already run is not scoping, they are selling.
How do you decide without overspending?
Start by knowing what you have. Our technical audit costs 190 EUR, with an initial diagnosis within 72 hours and a full report within 5 working days. The report states what your current ERP covers, what is missing and what each option would cost, with fixed figures. If you then hire us for the project, the 190 EUR is deducted from the budget. If not, you keep a document you can use to request quotes from anyone.
Two more conditions you should demand from any provider, whether you work with us or not. First: the code is yours from day 1, with repository access, so you can switch providers without rebuilding anything. Second: the engineer who quotes should be the one who builds. At ASD Solutions we work with senior engineers on staff in Spain, no subcontracting, and the same engineer who signs the quote delivers the project.
Frequently asked questions
How much does a custom ERP cost for an SME in Spain?
It depends on scope. A custom module on your current ERP costs between 1,500 and 8,000 EUR, an integration between systems runs 1,500 to 4,000 EUR, and a full ERP built from scratch starts at 15,000 EUR. The overall software investment range for an SME usually sits between 1,500 and 15,000 EUR.
Is a custom ERP better than adapting Sage, Holded or Odoo?
For around 8 out of 10 SMEs, adapting the ERP they already use is more cost-effective. A module of 1,500 to 8,000 EUR covers the specific process without losing what already works. A full custom ERP only pays off when the core business process fits no standard package or per-user licences inflate the annual cost.
How long does a custom module or ERP take to build?
A module or integration on an existing ERP is delivered in 3 to 6 weeks. A full custom ERP takes 2 to 4 months. Before starting, an initial diagnosis within 72 hours locks down scope and a fixed price, so the deadline is agreed in writing and does not grow during the project.
What does maintaining a custom ERP cost after delivery?
A technical retainer starts at 500 EUR per month and covers fixes, small improvements and monitoring. For one-off fixes without a monthly contract, prices start at 300 EUR. Software built properly on standard APIs needs less maintenance than one that patches the ERP core with every vendor update.
Does my company own the code of the custom ERP or module?
With us, yes. You receive the full source code, repository access and documentation from day 1, with no vendor lock-in. You can continue maintenance with your own team or another provider whenever you want. Demand this clause in writing from any agency: it is the difference between buying an asset and renting a dependency.
