What is LOD in BIM?
LOD (Level of Development) in BIM describes how detailed and reliable the model elements are—from conceptual placeholders (LOD 100) to as-built, fabrication-ready geometry (LOD 400). It matters for BIM estimating, quantity takeoffs, and coordination because it sets expectations for what the model can support.
LOD levels (summary)
| LOD | Typical use |
|---|---|
| LOD 100 | Concept / massing; not for takeoffs |
| LOD 200 | Generic elements, approximate quantities |
| LOD 300 | Specific elements, model elements = construction; suitable for many quantity takeoffs |
| LOD 350 | 300 + interfaces with other systems (e.g., clashes) |
| LOD 400 | Fabrication-ready; assembly and manufacturing |
| LOD 500 | As-built / field-verified |
Why LOD matters for estimating
- Scope — Estimating from LOD 300 assumes the model represents the design; LOD 400 implies fabrication-level detail.
- Accuracy — Quantities from a higher LOD are typically more reliable for cost estimates.
- Deliverables — Many BIM estimating and BIM-IQ workflows tag estimates with the LOD so everyone knows what the numbers are based on.
LOD 300 vs LOD 400
- LOD 300: Model elements are specific and suitable for coordination and most BIM quantity takeoffs; not necessarily fabrication-ready.
- LOD 400: Enough detail for fabrication, assembly, and installation; often used by MEP and specialty contractors for detailed estimates.
Understanding LOD helps you know what you can reliably estimate from a BIM and how to document your assumptions. BIM-IQ produces LOD-aware estimates so your deliverables match the model’s level of development.
Black Forge Technology can help — Get LOD-aware estimates with BIM-IQ or implement consistent BIM workflows with our consulting. Contact us today.