Can Tempered (Toughened) Glass Be Cut to Size?

Short answer

No. Tempered glass (often called toughened glass) cannot be cut, drilled, or reshaped after it has been tempered. Any attempt to do so will make it shatter. If you need a specific size, it must be cut and finished before the tempering process.

Why tempered glass can’t be cut once it’s toughened

Tempering is a heat treatment that makes glass stronger and safer. The glass is heated to a high temperature, then cooled very quickly. This locks the surface into compression and the core into tension. That’s what gives it strength, but it also makes the sheet very sensitive to edge damage or new stress points. If you try to saw, grind, or drill it, the stress balance collapses and the pane will break into small, blunt pieces.

How to get the size you need

If you need a precise size, shape, or cut-out, the correct process is:

1. Start with standard (annealed) glass.

2. Cut it to your required dimensions.

3. Add all holes, notches, and shaping.

4. Finish the edges.

5. Temper the finished piece.

This makes sure every change is built into the panel before toughening, so the glass stays safe in service.

At Best in Glass, we supply both stock and made-to-measure options for trade customers across the UK. Lead times vary with complexity and quantity. If timing is tight, call 01889 226444 or email contact@bestinglass.uk and we’ll advise what’s possible.

What can be specified before tempering?

You can ask for:

• Exact sizes to suit frames, channels, or clamps.

• Edge finishes such as flat-polished or arrised for a neat, safe edge.

• Holes and notches for hinges, brackets, or fittings.

• Shapes such as corners clipped off or curved profiles.

• Glass thickness to suit the application.

Getting this right up front avoids site issues later.

Typical uses where size matters

• Office and home partitions. Panels often need door cut-outs, U-channel tolerances, and hardware holes. See our range of glass partitioning systems for ideas and components.

• Balustrades and railings. Posts, clamps, and base shoes all set tight size limits. Order panels made to suit the exact fixing method. Learn more about our glass balustrades and railings.

• Furniture and interiors. Replacement tops, shelves, and protectors need clean edges and accurate sizes. We supply custom glass table tops for trade and domestic projects.

What about trimming a few millimetres on site?

It’s a common request, but the answer is still no. You can’t plane, grind, or sand a toughened pane smaller. Even light edge work can cause the sheet to fail. If a panel arrives slightly too big, the only safe fix is to reorder with the correct size.

Tolerances and measuring tips

Every glass factory works to small, standard tolerances. These are normal in manufacturing. To avoid reorders:

• Measure the opening in several places. Use the tightest measurement and allow a fitting clearance.

• Check hardware drawings. Hole centres, notch sizes, and edge distances must match the manufacturer’s data.

• Confirm thickness and edge type. This affects how the panel sits in channels and clamps.

• Provide accurate drawings. A clear sketch or CAD file with all dimensions saves time and questions.

If you’re unsure how much clearance to allow for your fixings, get in touch. Our team talks to installers every day and can help you plan the right gaps.

Do you ever cut after tempering?

No. There are niche industrial methods for altering pre-stressed glass, but they are not suitable for building or interior work. For trade projects, the rule is simple: if it’s toughened, do not cut it.

Alternatives when you need flexibility

• Order annealed first, then temper. Ideal when final sizes depend on site checks.

• Use laminated glass for some applications. Laminated can offer safety performance with different behaviour on breakage. It still needs all cutting and edge work done before any heat treatment.

• Consider removable trims or gaskets. Small size differences can sometimes be managed with the right fixing system. Speak to your hardware supplier early.

How we can help

Best in Glass is a Staffordshire-based supplier with nationwide delivery. Trades trust us for quick advice, helpful lead times, and a range of stock items backed by bespoke options. If you have drawings ready, send them over. If you’re still scoping the job, we can talk through tolerances and hardware choices so you order once and install with confidence.

Speak to us on 01889 226444 or email contact@bestinglass.uk

FAQs

Can tempered glass be cut to size after delivery?

No. Once toughened, glass cannot be cut, drilled, or reshaped. Reorder to the correct size.

Can you drill a hole in tempered glass?

No. Holes must be added before tempering. Provide exact sizes and locations when you place the order.

What if my panel is a few millimetres too big?

Do not try to grind or sand it. The pane will likely shatter. The safe solution is to reorder.

Is there a way to adjust fit on site?

Sometimes you can use different packers, gaskets, or trim details, but the glass size itself cannot change. Ask us for guidance.

Do you supply made-to-measure panels?

Yes. We supply custom sizes, edge finishes, holes, and shapes across the UK. Call 01889 226444 or email contact@bestinglass.uk for lead times.