Difference Between BOM, BOQ, and MTO in Construction Projects

On most projects, teams lose money for one simple reason: they use the wrong document for the wrong job. A BOQ gets treated like a purchase list. An MTO gets shared as if it’s a final procurement sheet. A BOM gets prepared too late—after site teams are already chasing materials.

Here’s the practical way to think about it:

• BOQ = commercial + contract control (tendering, billing, variations)
• MTO = quantity extraction for estimating and planning
• BOM = item-level procurement and fabrication/install readiness

If you’re a contractor, subcontractor, estimator, QS, PM, BIM lead, or procurement person—this guide shows what to use and exactly when.

What BOM, BOQ, and MTO actually mean

BOQ (Bill of Quantities)

A BOQ is a contract-style schedule that lists measured work items with descriptions, units, and quantities. Quantity surveyors and commercial teams use it to price tenders, value progress, and manage variations. It’s not built for “what to buy”—it’s built for “how to measure and pay.”

MTO (Material Takeoff)

An MTO is a quantity extraction of materials from drawings or a BIM model. Estimators use it to build takeoffs, compare options, and forecast costs. It’s faster than a BOQ for early-stage estimating because it stays close to the physical materials—but it can still be missing the “procurement-ready” details.

BOM (Bill of Materials)

A BOM is the most “real-world” document. It lists exact items you must procure, fabricate, track, and install—often including sizes, specs, part types, tags, and packaging by floor/zone/spool. This is where the bill of materials in construction becomes the backbone of procurement and site execution.

BOM vs BOQ vs MTO (quick comparison)

When contractors should use BOQ

Use a BOQ when you need a common commercial language across stakeholders—client, consultant, main contractor, and subcontractors.

In tendering, BOQ helps you price on a consistent structure. During execution, it supports progress valuation and change orders because it aligns to contract measurement. For project managers, BOQ also becomes a reporting tool to track commercial performance and cash flow.

Where teams go wrong is trying to convert BOQ directly into procurement. BOQ quantities are often measured under specific rules and may not match how you fabricate or install. It may group items too broadly or skip small-but-critical accessories that procurement can’t ignore.

When estimators and QS teams should use MTO

MTO is your most useful tool when you’re building an estimate, validating a BOQ, or planning early procurement. It stays closer to “what the project physically needs” than BOQ does, so estimators and quantity surveyors rely on MTO to avoid pricing blind.

MTO can come from manual takeoff (2D/PDF) or from BIM schedules. Both can work—what matters is consistency and checking assumptions. If you pull MTO from a model, you must confirm the model actually contains the right level of detail and isn’t filled with placeholders.

MTO becomes risky when teams treat it like a final BOM. Many MTOs don’t include supports, hangers, fixings, wastage logic, lap allowances, or system accessories. That’s why MTO should feed into procurement planning—but procurement should still be driven by BOM.

When subcontractors and procurement teams should use BOM

If you’re ordering materials, BOM is the document that prevents chaos. A strong BOM answers procurement questions without back-and-forth:

• What exact items do we need?
• In what sizes/specs?
• How many, by location/zone/floor?
• What has changed since the last revision?

This is why the bill of materials in construction is not just a spreadsheet—it’s a control system for purchasing, deliveries, inventory, and installation sequencing.

For trades like MEP, steel, façade, and modular work, BOM becomes even more critical because fabrication and installation depend on item-level accuracy (fittings, valves, connectors, accessories, and packaging logic).

The simplest decision guide

If you remember only this, you’ll avoid most of the mistakes:

• Pricing/tendering and contract payments: use BOQ
• Estimating and quantity verification: use MTO
• Procurement, fabrication, delivery tracking: use BOM

Most profitable teams don’t choose one—they connect all three in a clean workflow.

The workflow that actually works on real projects

A practical, contractor-friendly flow looks like this:

Step 1: MTO for estimating and planning
You extract quantities (from drawings or BIM) to build your cost estimate and identify long-lead materials.

Step 2: BOQ (or schedule of values) for commercial structure
You align scope, pricing, billing, and change orders to the contract structure so commercial control stays clean.

Step 3: BOM for procurement and execution
You convert measured quantities into purchase-ready items, then package them by workface (floor/zone/system/spool) so site teams can install without confusion.

This flow keeps estimators, QS teams, project managers, BIM professionals, and procurement aligned—without forcing one document to do a job it was never designed to do.

How BIM changes BOM and MTO 

BIM can improve speed and accuracy—but only if the model is built and maintained with quantity output in mind. Many teams assume “the model is there, so quantities are correct.” That’s a costly assumption.

BIM-based outputs become reliable when parameters are consistent, systems are modeled correctly, duplicates are controlled, and revisions are tracked. If the model is messy or incomplete, automated schedules will produce confident-looking numbers that are still wrong.

That’s exactly where the bim bill of materials services come in. Contractors and subs often use these services to clean models, standardize parameters, extract structured schedules, and deliver procurement-ready BOMs or estimator-ready MTOs. The value isn’t “BIM magic.” The value is usable, auditable outputs tied to scope and revisions.

Bill of materials for building permit — when is it needed?

A bill of materials for building permits is not always mandatory, but it becomes relevant when authorities require specific schedules or documentation that supports code compliance or plan review.

In practice, permit-related material documentation often looks like:

• door/window schedules and glazing specs
• fixture and equipment schedules (plumbing, HVAC, fire)
• material specs tied to fire ratings, energy compliance, insulation, etc.

Don’t submit your procurement BOM as a permit document unless the jurisdiction asks for it. Permit reviewers typically want code- and drawing-aligned schedules, not purchasing packages. The smart approach is to produce a “permit-friendly materials/equipment schedule” that uses accurate data but stays aligned with permit requirements.

Common mistakes that blow budgets and delay procurement

The most common failures are not technical—they’re process mistakes:

Using BOQ as a buying list. BOQ rarely includes every accessory or reflects fabrication reality.
Treating MTO as final procurement. MTO often lacks supports, fixings, wastage, and packaging.
No revision control. One late design change can make last week’s BOM dangerous.
No location breakdown. A BOM without floor/zone packaging creates site-level confusion and material loss.
Assuming BIM quantities are automatically correct. BIM output is only as good as the model rules and discipline.

Practical best practices you can implement immediately

You don’t need a new software stack to improve this. You need discipline:

1. Separate estimating quantities from procurement quantities. Let MTO drive estimating; let BOM drive buying.
2. Standardize templates. Use consistent naming, units, and classification so teams don’t rebuild formats for each project.
3. Package BOM by workface. Floor/zone/system/spool packaging reduces site waste and improves installation speed.
4. Track revisions like a contract deliverable. Record version, date, drawing/model reference, and change notes.
5. Run cross-checks. Compare model-based outputs with drawing-based sanity checks on critical systems.