Overlock Thread Consumption Calculator

What is Overlock Thread Consumption?

Overlock thread consumption means the total amount of thread used in overlock stitching. In garment factories, overlock stitches are used for edge finishing and seam locking. Knowing the correct thread consumption helps reduce waste and control production costs.

Why Overlock Thread Calculation Is Important in the Garment Industry

Every garment requires thread for stitching. Overlock machines use 3 to 5 threads. If we do not calculate the thread correctly, it leads to wastage. Overuse of threads increases cost. Underuse causes thread shortage in production. Accurate thread estimation helps planning, costing, and procurement.

Common Areas Where Overlock Thread Is Used

• Side seams of T-shirts
• Armhole seams
• Bottom hems
• Neck joint seams

In most knit garments, overlock stitching is common. Many factories use 4-thread overlock machines for strength.

Overlock Thread Consumption Formula

The standard formula used to calculate overlock thread consumption is:

Thread Consumption (in meters) = Seam Length (in inches) × SPI × Number of Threads × 0.0254

Where:

• SPI = Stitch Per Inch
• Seam Length = Total seam length
• Number of Threads = Usually 3 or 4
• 0.0254 is the conversion factor from inches to meters

Example of Overlock Thread Calculation

Let’s say:

• Seam Length = 20 inches
• SPI = 12
• Number of Threads = 4

Now apply the formula:

Thread = 20 × 12 × 4 × 0.0254 = 24.384 meters

This means 24.38 meters of thread will be consumed for that seam.

Factors That Affect Overlock Thread Consumption

Stitch Per Inch (SPI)

Higher SPI means more stitches in one inch. More stitches need more thread. A 14 SPI will use more thread than a 10 SPI.

Seam Length

Longer seams use more thread. If a T-shirt has longer side seams, it will need more overlock thread.

Number of Threads

3-thread and 4-thread overlocks use different amounts. A 4-thread overlock consumes more thread than a 3-thread.

Thread Type

Some threads are thicker. Coarse threads consume more volume. Fine threads consume less, but the length may be more.

Standard SPI for Overlock

In general:

• Knit garments = 12 SPI
• Heavy fabric = 10–11 SPI
• Light fabric = 13–14 SPI

Factories choose SPI based on fabric type and machine settings. It is best to fix a standard SPI for a style before bulk production.

Benefits of Using a Thread Consumption Calculator

Using a calculator makes thread estimation simple. Operators can enter the seam length, SPI, and number of threads. The calculator shows the thread in meters. This avoids manual errors. It helps merchandisers, planners, and production managers.

Who Uses Overlock Thread Calculators

• Industrial engineers
• Production planners
• Merchandisers
• Cutting and sewing floor managers
• Sampling and costing teams

How to Reduce Overlock Thread Wastage

Monitor SPI Setting

Check if SPI is too high. If not required, reduce SPI to save thread.

Use the Right Thread Cone

Using too thick a thread may increase consumption. Choose the right thread count for the fabric and machine.

Avoid Re-stitching

Re-stitching wastes thread. Maintain proper machine settings and operator training to reduce rework.

Calculate Before Production

Use the calculator before production. It helps prepare the right amount of thread cones for the job.

Supporting Tools for Better Production

Many factories use digital calculators or software to track thread usage. These tools help in:

• Reducing inventory loss
• Saving cost
• Ensuring thread availability during sewing

Overlock calculators help avoid both shortage and excess.

Best Practices in Thread Consumption Management

• Fix SPI in sample approval
• Record actual thread use during trial
• Compare the calculator output with the actual result
• Use the result to adjust planning for bulk

Final Thoughts

Accurate overlock thread consumption is essential in textile manufacturing. It helps save cost and time. It improves production flow. By using the formula or calculator, factories can maintain better control over thread usage. Always follow standard SPI and record your data for continuous improvement.