What is MRL (Manufacturing Readiness Level)?

A ten-point scale, developed for US defence acquisition, for how mature a programme’s manufacturing is, from basic manufacturing implications identified at MRL 1 to full-rate production demonstrated at MRL 10.

What MRL is

Manufacturing Readiness Level is the scale US defence acquisition uses to judge whether a programme can be manufactured at the cost, rate and quality it needs. It runs from 1 to 10. The criteria for each level are set out in the MRL Deskbook across nine threads, covering areas such as the industrial base, design, cost and funding, materials, process capability, quality and the manufacturing workforce. The Deskbook offers MRL as a best practice rather than a requirement, and treats each level as a target for a stage of a programme rather than a pass mark.

It is a serious instrument. Earlier evaluations of manufacturing risk lacked uniform metrics; MRL gave them one. Used properly it forces manufacturing questions to be asked before money is committed, and it gives a programme office, a prime and a supplier one shared vocabulary. That is more than most commercial investment processes manage.

Where it came from

MRL was developed by a joint defence and industry working group, sponsored by the Joint Defense Manufacturing Technology Panel, and introduced to the defence community in 2005. The MRL Deskbook is prepared by the Office of the Secretary of Defense Manufacturing Technology Program with the Joint Service/Industry MRL Working Group, and has been revised several times, most recently in May 2025.

The levels are tied to acquisition milestones: MRL 4 by the end of Materiel Solution Analysis, ahead of Milestone A; MRL 6 for Milestone B; MRL 8 for Milestone C and the start of low-rate initial production; MRL 9 to begin full-rate production. A 2010 GAO review found no department-wide policy requiring MRL assessments; since 2011, US defence rules have required manufacturing readiness to be considered when major programmes choose suppliers.

The ten levels, in brief

• MRL 1 to 3: concept. Basic manufacturing implications identified; manufacturing concepts identified; manufacturing proof of concept developed.
• MRL 4 to 6: prototype. Capability to produce the technology prototype in a laboratory environment (4); prototype components in a production-relevant environment (5); a prototype system or subsystem in a production-relevant environment (6).
• MRL 7 to 8: pilot. Capability to produce systems, subsystems or components in a production-representative environment (7); pilot line capability demonstrated, ready to begin low-rate initial production (8).
• MRL 9 to 10: production. Low-rate initial production demonstrated, with capability in place to begin full-rate production (9); full-rate production demonstrated and lean manufacturing practices in place (10).

What it measures well

MRL is strongest where a programme has a defined product, a known customer and a procurement chain to answer to. It is good at:

• making manufacturing a gated question rather than an afterthought;
• separating a laboratory capability from a production-relevant one, and a pilot line from a rate;
• covering cost, supply base and people as well as the process itself, so a programme cannot score on equipment alone;
• giving a government buyer a consistent basis for comparing programmes.

What it misses for hard-tech deployment

MRL scores a programme’s manufacturing maturity. It does not show the distance between the technology and the manufacturing rails it has to run on: the materials, process windows, tooling, supply and yield behaviour that the existing industrial economy already knows how to make. A programme can score well on its own manufacturing and still sit a long way from a process the wider industry can reproduce. That distance is what Kaipability calls the Coupling Gap.

Two further limits matter to a commercial reader. MRL was written for acquisition programmes with a government customer and a defined requirement; its funding questions ask whether a programme’s money is adequate, not whether a company can raise it, and a venture-backed company has no programme office behind it. And an MRL is a target for a stage of a programme, not evidence that the process holds on the nth consecutive build. Capital deciding on a hard-tech company needs both ladders, read together, by someone who has run the line.

How MRL relates to TRL and to MCRL

TRL, Technology Readiness Level, is a nine-point scale for how mature the technology is. MRL sits beside it and asks about manufacturing. The Deskbook says the two are generally related but do not align one-to-one, and that technology and manufacturing maturity can progress at different rates. That difference is the reason both are needed.

MCRL, Manufacturing Capability Readiness Level, is a different scale. It was created at Rolls-Royce by Michael Ward and published with Halliday and Foden in 2012. It has nine levels, one for each level of TRL, and asks whether a capability, rather than a programme, is ready to make the thing. MCRL is Rolls-Royce’s, not ours: Kaipability adopts it, attributes it and extends it. Set MCRL against TRL and the gap between the two ladders is the Coupling Gap. Reported honestly to a board or an investment committee, that is Deployment Readiness.