Material Take-Off (MTO) for Steel Fabrication: Complete Guide with Example

Material Take-Off (MTO) is one of the most important activities in steel fabrication and construction. Before a fabrication shop starts cutting plates, ordering sections or preparing assemblies, the required materials need to be identified and quantified.

A properly prepared MTO helps production engineers, fabrication engineers, project managers and procurement teams understand what materials are required, how much is required and where those materials will be used.

In this guide, we will explain how to prepare an MTO for steel fabrication, how to calculate steel weight, how to account for wastage and the common mistakes that can increase project cost.

📋 MTO Quick Summary

MTO = Material identification + Quantity + Size + Weight + Specification

A typical steel fabrication MTO may contain plates, beams, channels, angles, pipes, tubes, flats, round bars, bolts, welding consumables and other project-specific materials.

What Is Material Take-Off?

Material Take-Off is the process of extracting the required materials and quantities from engineering drawings, fabrication drawings, 3D models, specifications and other project documents.

For a steel fabrication project, an MTO normally identifies:

Material type
Material grade
Thickness or section size
Length
Width
Quantity
Unit weight
Total weight
Required quantity for fabrication
Estimated wastage

The final format depends on the company's project requirements and procurement system.

Why Is MTO Important in Steel Fabrication?

An accurate MTO provides the foundation for material procurement and production planning.

If the MTO is incorrect, the project may face material shortages, excess inventory, unnecessary scrap, procurement delays and cost overruns.

1. Procurement Planning

The procurement team can use the MTO to identify which materials need to be purchased and in what quantities.

2. Production Planning

Production engineers can understand the material requirements before fabrication begins.

3. Cost Estimation

Material quantity and weight are major inputs when estimating steel fabrication cost.

4. Inventory Control

The MTO helps compare required material against available stock.

5. Scrap Control

Actual material consumption can be compared with the planned quantity to monitor fabrication wastage.

6. Project Scheduling

Material availability directly affects cutting, fit-up, welding and assembly activities.

MTO vs BOM: What Is the Difference?

MTO and BOM are closely related, but they are not always used for exactly the same purpose.

MTO	BOM
Focuses on material quantities required for a project or scope.	Focuses on components and materials required to build an assembly/product.
Commonly used for procurement and estimation.	Commonly used for manufacturing and assembly.
Can include bulk materials such as plates and sections.	Often organized by assembly and sub-assembly.

In many fabrication companies, the terms can overlap, and the exact terminology depends on the organization's engineering and ERP procedures.

Information Required to Prepare an MTO

Before starting an MTO, collect the latest approved project documents.

General Arrangement (GA) drawings
Fabrication drawings
Assembly drawings
Part drawings
Material specifications
Structural steel specifications
Project standards
Welding requirements
Bill of Materials, if available
Revision-controlled drawings
Approved material grades

⚠️ Important:

Always make sure the MTO is prepared using the latest approved drawing revision. Using an outdated revision can result in incorrect material procurement.

Typical Materials Included in a Steel Fabrication MTO

Depending on the project, an MTO may contain several different material categories.

Material	Examples
Plates	MS plates, structural plates, base plates
Beams	I-beams, H-beams
Channels	C-channels, U-channels
Angles	Equal and unequal angles
Pipes	Structural and process pipes
Tubes	Square and rectangular hollow sections
Flats	Flat bars and strips
Round Bars	Solid round bars
Fasteners	Bolts, nuts and washers

Basic Steel Plate Weight Calculation

One of the most common calculations in a steel fabrication MTO is plate weight.

For carbon steel, a commonly used density for estimation is approximately 7850 kg/m³.

Plate Weight (kg) = Length (m) × Width (m) × Thickness (m) × Density

For dimensions in millimetres, the formula can be simplified to:

Weight (kg) = L(mm) × W(mm) × T(mm) × 0.00000785

Example: Steel Plate Weight

Consider a steel plate:

Length = 2000 mm
Width = 1000 mm
Thickness = 10 mm

Using the formula:

2000 × 1000 × 10 × 0.00000785

Weight = 157 kg approximately

If the MTO requires 10 such plates:

157 × 10 = 1570 kg

Calculating Structural Section Weight

For standard structural sections such as beams, channels and angles, the easiest method is normally to use the manufacturer's or applicable steel-section table for the nominal mass per metre.

For example, if a particular structural section weighs 20 kg/m and the required total length is 50 m:

20 × 50 = 1000 kg

The calculated theoretical weight is therefore approximately 1000 kg.

Actual procurement weight may differ depending on supply length, section availability and the applicable material standard.

How to Prepare an MTO Step by Step

Step 1: Collect the Drawings

Collect all approved GA, fabrication, assembly and part drawings required for the project scope.

Step 2: Check Drawing Revisions

Verify the revision number and issue status of each drawing.

Step 3: Identify Materials

Read the drawings and identify plates, beams, channels, angles, pipes, tubes, flats and other materials.

Step 4: Record Material Specifications

Record the material grade and applicable specification.

For example, a project may require a particular structural steel grade. The exact grade should always be taken from the approved project documentation.

Step 5: Record Dimensions

For plates, record length, width and thickness. For sections, record section designation and required length.

Step 6: Calculate Quantity

Determine the number of pieces required for each component.

Step 7: Calculate Theoretical Weight

Calculate or obtain the nominal unit mass and multiply it by the required quantity or length.

Step 8: Consider Procurement Requirements

Standard stock lengths and commercially available plate sizes may differ from the exact dimensions shown on fabrication drawings.

Step 9: Consider Wastage

Estimate cutting and nesting losses where appropriate. Avoid adding an arbitrary wastage percentage without understanding the actual cutting plan.

Step 10: Review the MTO

Cross-check the MTO against drawings, assemblies and available material before releasing it for procurement.

Sample Steel Fabrication MTO

The following is a simplified example of an MTO for a fabricated steel frame.

Item	Material	Size	Qty	Approx. Weight
1	Steel Plate	10 × 2000 × 1000 mm	10	1570 kg
2	Structural Section	20 kg/m	50 m	1000 kg
3	Flat Bar	10 × 50 mm	30 m	Approx. calculated weight

This is only a simplified example. A project MTO should contain all relevant fields required by the engineering, procurement, quality and production teams.

What Is Material Wastage?

Material wastage is the portion of purchased material that does not become part of the finished fabricated component.

In steel fabrication, wastage can occur because of:

Plate nesting losses
Cutting kerf
End cuts
Trim cuts
Incorrect cutting
Damaged material
Unused remnants
Fabrication changes

How to Calculate Material Wastage

A simple way to calculate material wastage is:

Wastage % = (Purchased Weight − Used Weight) ÷ Purchased Weight × 100

Example

Suppose a fabrication shop purchases 10,000 kg of steel and uses 9,400 kg in the finished components.

Wastage = 10,000 − 9,400

Wastage = 600 kg

Wastage % = 600 ÷ 10,000 × 100

Wastage = 6%

Material Nesting and MTO

MTO preparation should ideally be connected with material nesting and cutting optimization.

For example, a fabrication drawing may require several small plates. Instead of purchasing individual plates for every component, the components can potentially be nested on larger standard plates to reduce scrap.

Good nesting can help:

Reduce material waste
Reduce purchasing cost
Improve plate utilization
Reduce scrap generation
Improve cutting productivity

MTO and Material Traceability

Material identification should not stop after procurement. In controlled fabrication projects, material traceability is important throughout production.

Depending on project requirements, traceability may include:

Heat number
Material grade
Material certificate
Plate or section identification
Cut-piece identification
Assembly identification

Traceability requirements vary by project and governing specification.

Common MTO Mistakes

1. Using an Old Drawing Revision

This is one of the most common causes of incorrect material quantities.

2. Missing Small Components

Small brackets, stiffeners, clips and connection plates can easily be missed when reviewing large assemblies.

3. Incorrect Unit Conversion

Mixing millimetres, metres, kilograms and tonnes can create significant errors.

4. Ignoring Section Length

The total required length and commercially available stock lengths should both be considered.

5. Adding Excessive Wastage

A large blanket wastage percentage can inflate procurement quantities unnecessarily.

6. Ignoring Cutting Optimization

Theoretical material quantity and actual procurement quantity are not always identical.

7. Not Cross-Checking Assemblies

A good MTO should be checked against assembly and part drawings to reduce omissions and duplication.

How MTO Helps Reduce Fabrication Cost

Material is often one of the largest cost components in steel fabrication. An accurate MTO can therefore have a direct impact on project profitability.

A good MTO helps reduce cost by:

Preventing over-purchasing
Reducing material shortages
Improving nesting
Reducing scrap
Improving inventory control
Supporting accurate quotations
Improving production planning

MTO Workflow in a Fabrication Shop

Engineering Drawings

↓

Material Identification

↓

Quantity Calculation

↓

Weight Calculation

↓

Material Nesting / Optimization

↓

Procurement MTO

↓

Material Receipt & Inspection

↓

Cutting & Fabrication

↓

Actual Consumption Tracking

Practical Tips for Production Engineers

Keep drawing revisions under control. Always work with approved documents.
Separate theoretical and procurement quantities. Theoretical weight may not equal actual purchase quantity.
Track actual consumption. Compare MTO quantity against material issued to production.
Monitor scrap. Record the reason for major material losses.
Coordinate with procurement. Confirm commercially available sizes and stock lengths.
Coordinate with production. Cutting plans can influence actual material requirements.
Use standard material sizes whenever practical. This can simplify procurement and reduce waste.

Conclusion

A Material Take-Off is much more than a list of steel materials. It connects engineering, procurement, production, inventory control and project cost.

For steel fabrication projects, an accurate MTO should identify the material type, grade, size, quantity and theoretical weight while also considering procurement constraints and realistic cutting requirements.

The best results come when the MTO is continuously compared with actual material consumption. This allows fabrication teams to identify excessive scrap, improve nesting and control project costs.

Whether you are preparing an MTO for a small fabrication job or a large structural steel project, the basic principle remains the same:

Right Material + Right Quantity + Right Specification + Controlled Waste = Better Fabrication Planning

Frequently Asked Questions

What is MTO in steel fabrication?

MTO stands for Material Take-Off. It is a detailed list of the materials, specifications, sizes and quantities required for a fabrication project.

What materials are included in a steel fabrication MTO?

Typical materials include steel plates, beams, channels, angles, pipes, tubes, flats, round bars, fasteners and other project-specific materials.

How is steel plate weight calculated?

For dimensions in millimetres, a commonly used formula for estimating carbon-steel plate weight is: Length × Width × Thickness × 0.00000785.

What is the difference between MTO and BOM?

MTO generally focuses on material quantities for procurement or project estimation, while BOM commonly organizes the components and materials required to manufacture an assembly or product. The exact usage varies between organizations.

Should wastage be included in MTO?

Potential fabrication and cutting losses should be considered when determining procurement quantities, but the allowance should be based on the actual cutting and nesting strategy rather than an arbitrary percentage.

Who prepares an MTO?

Depending on the organization, an MTO may be prepared or verified by engineering, estimation, planning, procurement or production teams.

Why is MTO important for fabrication engineers?

It helps fabrication engineers plan material availability, cutting activities, production requirements, inventory and material utilization.

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