What Is Engineer-to-Order (ETO)?
Also known as: ETO, engineered to order, project manufacturing
Definition
Engineer-to-order (ETO) is a manufacturing strategy where each product is designed and engineered to a specific customer's requirements after the order is received. Design, BOM and routing are created per project rather than reused from a catalog.
Engineer-to-Order (ETO) Explained
ETO is the most customized of the production strategies. Typical examples are industrial machinery, custom tooling, process equipment, shipbuilding and aerospace ground equipment. Because design is part of the order, the quote is an estimate based on partial information, and costs and lead times carry more uncertainty than in make-to-stock or make-to-order environments.
ERP requirements differ from standard manufacturing. You need project or job-level structures to hold the evolving BOM, engineering change management, milestone or percent-complete billing, and cost tracking by project. Infor LN has strong project pegging and engineering features, Infor SyteLine uses the Projects and Estimates modules and job orders, SAP uses Project System with WBS elements, and Epicor and IFS have project-oriented ETO functionality.
The BOM is often incomplete at the time of ordering. Engineering releases it in stages, which means purchasing of long-lead items has to start from a preliminary structure. Manufacturers manage this with placeholder items, phantom assemblies and carefully controlled revisions to avoid buying against obsolete designs.
Weak points are estimating accuracy and change control. Historical project data is the best input for estimating, which is a strong use case for retrieval over past jobs. Any suggestion should be treated as an input to the estimator, not a price.
Why It Matters
- Margin depends on estimating accuracy, since each project is effectively unique.
- Engineering changes after order are expensive, so revision control and change orders must be tied to cost and schedule.
- Long-lead purchasing before design completion creates financial risk that needs visibility.
- Project billing and WIP tracking are essential for cash flow on multi-month builds.
In Practice
A packaging machine builder wins a 14-month order. Engineering releases the frame BOM in month 2 and the controls BOM in month 5. Purchasing places the gearbox order in month 1 from the preliminary design. A customer change in month 6 alters the conveyor length, and the ERP must show the cost, delayed items and billing milestone impact before the change is approved.
Frequently Asked Questions
What is the difference between ETO and MTO?
In make-to-order the product design already exists and is built after an order. In engineer-to-order the design itself is created or modified per customer order.
What ERP features matter for ETO?
Project or job structures, staged BOM release, engineering change control, milestone billing and cost tracking by project.
Why is ETO quoting difficult?
Design is incomplete at quote time, so cost and duration rely on estimates from similar past projects and contingency allowances.
Can AI help ETO manufacturers?
Yes, mainly by searching past projects, drawings and cost records to support estimating. Engineers still validate the result.
Related Terms
Make-to-Order (MTO)
Make-to-order (MTO) is a production strategy where a product is manufactured only after a confirmed customer order, using existing designs and routings. It avoids finished goods inventory but gives the customer a lead time equal to procurement plus production time.
Configure, Price, Quote (CPQ)
Configure, Price, Quote (CPQ) is software that guides a salesperson through selecting valid product options, calculates the price from rules and discounts, and produces a quote document, then passes the accepted configuration to the ERP as a sales order.
Project Pegging
Project pegging in Infor LN links demand, supply, inventory and cost to a specific project, element or activity. Pegged material is reserved for that project only and its costs flow to the project budget, which is how contract-driven manufacturers segregate program inventory.
Job Costing
Job costing accumulates material, labor, subcontract and overhead costs against a specific job or work order, so each order has its own actual cost and margin. It suits make-to-order and engineer-to-order shops where every job differs.
Estimate Job
An estimate job in SyteLine is a non-production job used to cost a potential order. It carries materials and routing operations like a real job so SyteLine can calculate a full cost, but it creates no demand, consumes no inventory, and is ignored by planning.
Working with Engineer-to-Order (ETO) in a live environment? Our engineers do this every day - and our AI agents automate most of it.