How does the cutting optimiser work?

The optimiser uses a first-fit decreasing (FFD) bin packing algorithm. It sorts your required lengths from longest to shortest, then places each piece on the first stock length where it fits. This heuristic typically achieves waste levels within 10-15% of the theoretical optimum, which is excellent for practical use.

What stock lengths should I choose?

Common UK timber stock lengths are 2.4m (8ft), 3.0m (10ft), 3.6m (12ft), and 4.8m (16ft). Longer stock is generally more economical per metre but harder to transport. Choose the shortest stock that fits your longest required piece. The optimiser will show you which stock length produces the least waste overall.

What is kerf width and why does it matter?

Kerf is the width of material removed by the saw blade — typically 3mm for a standard circular saw blade. For each cut, you lose one kerf width. Over many cuts, this adds up. For example, 10 cuts at 3mm each loses 30mm of material. The optimiser accounts for kerf in its calculations.

How do I enter my required lengths?

Enter your required lengths as comma-separated values in metres. For example: 1.2, 0.8, 1.5, 0.6, 1.2 for five pieces. Duplicate values are allowed — if you need four pieces of 1.2m, enter: 1.2, 1.2, 1.2, 1.2. The optimiser handles any number of pieces.

What is a usable offcut?

A usable offcut is a remaining piece of stock that is long enough to be used for future projects. The default minimum is 200mm, but you can adjust this in advanced options. Keeping track of usable offcuts helps reduce overall waste across multiple projects.

TradeCalculator

Timber Cutting Optimiser

Enter required lengths and find the optimal arrangement on stock lengths to minimise waste. Uses first-fit decreasing bin packing algorithm.

Required Lengths (metres, comma-separated)

Enter all pieces you need to cut, separated by commas

Stock Length

Available timber length

Price Per Stock Length (optional)

Your supplier's price per length

How We Calculate This

This optimiser arranges your required timber lengths onto stock lengths using a first-fit decreasing algorithm. It sorts pieces largest-first and places each on the first stock length with enough remaining space.

The algorithm

1. Sort required lengths from longest to shortest
2. For each piece, find the first stock with enough space
3. Account for kerf (saw blade width) per cut
4. Waste = Stock length - Sum of cuts - Kerfs

This greedy approach typically produces results within 10-15% of optimal. For critical jobs, try different stock lengths to compare waste percentages.

Waste reduction tips

Try different stock lengths — sometimes 3.6m wastes less than 4.8m
Group similar lengths together when cutting
Save usable offcuts for smaller projects
Allow 3mm per cut for saw kerf

Frequently Asked Questions

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Last updated: March 2026

All calculations are estimates. Verify with your supplier.