🪵 Why a “2×4” Isn’t Always Exactly 2×4
If you’ve ever ordered timber in the UK, you’ve probably noticed that sizes can be described using both imperial and metric measurements. This can feel confusing at first — especially when the size you receive doesn’t match the numbers you had in mind.
This page explains why that happens, and how to order timber with confidence.
🇬🇧 Why the UK Uses Both Imperial and Metric
Since 1 January 2000, UK retail regulations require timber to be sold using metric measurements.
However, many tradespeople and DIY customers still use traditional imperial terms such as:
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2×4
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4×2
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1×6
These terms are deeply ingrained in the industry and are still widely used as shorthand — even though the actual timber is supplied in metric sizes.
As a result, the UK timber trade now operates using a mix of both systems.
📏 Imperial to Metric: Not an Exact Match
Imperial and metric sizes do not convert perfectly.
For example:
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A true 2" × 4" equals 50.8mm × 101.6mm
In reality, timber merchants don’t supply timber to those exact measurements. Instead, sizes are rounded to standard metric dimensions, typically within a few millimetres.
So when someone asks for:
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2×4 timber
What they usually receive is:
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50mm × 100mm
This rounding is normal, industry-standard, and expected.
✅ Why Metric Sizes Matter
Because imperial sizes don’t convert exactly, metric measurements should always be treated as the accurate size.
When ordering timber:
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Metric sizes define the actual dimensions supplied
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Imperial sizes are best viewed as traditional references, not precise measurements
Specifying metric sizes removes ambiguity and ensures you get exactly what you need for your project.
🛠 How Timber Merchants Interpret Sizes
Across the UK timber trade, it’s generally assumed that:
If a customer asks for an imperial size, they are referring to the nearest metric equivalent.
So:
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2×4 = 50mm × 100mm
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4×2 = 100mm × 50mm
This isn’t guesswork — it’s long-established industry practice.
🌲 Our Approach at Nottage Timber Merchants
At Nottage Timber Merchants, we understand that customers think and work in different ways.
That’s why:
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We display both metric sizes and imperial equivalents on our products
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Metric sizes are always shown as the primary reference
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Imperial measurements are included as a helpful guide
This approach helps bridge the gap between traditional terminology and modern standards — without confusion.
🧠 In Summary
✔ Timber in the UK is sold in metric sizes
✔ Imperial sizes are still widely used as shorthand
✔ Conversions are approximate, not exact
✔ Always rely on metric dimensions for accuracy
If you’re ever unsure which size is right for your project, our team is always happy to help — just ask.