Scrap Calculator

The Scrap Calculator is a simple tool that helps you quickly figure out cutting patterns without creating a full order. It’s useful for quick quotes or rough estimates.

What is Scrap Rate?

When you cut steel bars into smaller pieces, there’s always some material left over that’s too short to use. This is called “scrap” or “waste.”

Scrap rate is the percentage of material that becomes waste.

Example:

You have a 12,000mm (12m) bar
You need to cut pieces that are 3,500mm long
You can cut 3 pieces = 10,500mm used
Leftover: 1,500mm (too short to use) = 12.5% waste

Why calculate scrap rate:

Estimate material costs accurately
Give customers better quotes
Know how much extra material to order
Compare efficiency of different cutting approaches

Using the Calculator

Basic Calculation

Open the Scrap Rate Calculator from the sidebar and you’ll see a number of input fields:

Bar Length

Enter the length of the bars you have (in millimeters)
Example: 12000 for a 12-meter bar

Piece Length

Enter the length of pieces you need to cut (in millimeters)
Example: 3500 for a 3.5-meter piece

Allowance (optional)

Enter extra length for saw blade width if needed
Usually 5-10mm per cut
Example: 5

Once you have filled in the form, Click Calculate

Understanding Results

What You’ll See

The calculator shows:

Pieces per Bar

How many complete pieces you can cut from one bar

Total Used

How many millimeters are used for cutting pieces

Waste per Bar

How many millimeters are left over (too short to use)

Scrap Rate

Percentage of material that becomes waste
Lower is better!

Example Result

Bar Length: 12,000mm
Piece Length: 3,500mm
Allowance: 5mm per cut

Results:
Pieces per Bar: 3
Total Used: 10,515mm (3,500 + 5 + 3,500 + 5 + 3,500)
Waste per Bar: 1,485mm
Scrap Rate: 12.4%

Comparing Options

Use the calculator to compare different approaches:

Example: Finding the Best Bar Length

Option 1: Using 12-meter bars

Piece needed: 3,500mm
Pieces per bar: 3
Waste: 1,500mm (12.5%)

Option 2: Using 6-meter bars

Piece needed: 3,500mm
Pieces per bar: 1
Waste: 2,500mm (41.7%)

Option 3: Mix of lengths from 12-meter bars

Pieces: 3,500mm and 4,000mm
Waste: 1,000mm (8.3%)

Result: Option 3 is most efficient!

Tip
Try different combinations to find what minimizes waste.

Using Results for Quotes

When a customer requests a quote:

Enter their required piece length
Check the scrap rate
Add the waste percentage to your material cost
Include it in your price

Example pricing:

Customer needs 100 pieces at 3,500mm
Your bar costs $100 per bar
Scrap rate: 12.5%
True material cost: $100 + ($100 × 12.5%) = $112.50 per bar worth of material

Ordering Material

When ordering stock:

Calculate how many pieces you can get per bar
Calculate scrap rate
Order extra to account for waste

Example:

Need: 100 pieces
Pieces per bar: 3
Bars needed: 34 bars (100 ÷ 3 = 33.3, round up)
With 12.5% waste, order a couple extra bars for safety

Common Questions

Why does my actual waste differ from the calculator?

The calculator assumes perfect cuts. In practice, you may have additional factors like:

Variations in bar length
Saw blade width (kerf) - use the allowance field for this
End trimming requirements
Crooked bars requiring extra trimming

Should I include saw blade width?

Yes, use the allowance field. A typical saw might remove 5-10mm per cut.

What’s a good scrap rate?

Under 2.5% - Excellent efficiency
2.5-5% - Good, typical for many operations
5-7.5% - Acceptable but look for improvements
Over 7.5% - High waste, try to find better combinations

Can the calculator help me plan actual cutting?

It’s a quick estimation tool. For detailed cutting plans with your actual inventory and orders, use the Cut Long Products (Optimization) feature.

What if I need many different lengths?

For complex requirements with many different pieces, the Optimization tool is better - it handles mixed lengths and multiple bars automatically.

Tips for Reducing Scrap

Mix lengths when possible - Combine different piece lengths from one bar
Choose bar lengths wisely - Stock bars that divide well into common piece sizes
Nest orders - Group orders that work well together
Use optimisation - For complex cuts, let the optimiser find the best pattern
Keep waste pieces - Short drops might be useful for future small orders

Next Steps

After calculating scrap rates:

Check inventory - See what bar lengths you have
Review orders - Look for opportunities to combine lengths
Run optimisation - Get detailed cutting plans for actual production

Remember
Smart scrap rate planning means better quotes, lower costs, and happier customers!