How to Cut Upholstery Foam – Tools, Tips & What to Avoid

If you’ve ever tried to cut upholstery foam with a blunt knife, you’ll know it’s like trying to slice a marshmallow with a spoon — messy, uneven, and downright annoying.

The good news? With the right tool and a steady hand, you can cut foam cleanly and professionally, even in your own workshop or garage.

At Foam4U, we’ve spent years cutting every kind of foam imaginable — from soft sofa grades to dense marine cushions — and we’ve seen every method under the sun. Some work brilliantly. Others… well, should stay on YouTube where they belong.

Let’s go through what works, what doesn’t, and how to get the best results.

⚠️ Don’t Use a Hot Wire Cutter

Let’s clear this up right now. Hot wire cutters are for styrofoam — not upholstery foam.
Polyurethane and most other upholstery foams release toxic fumes when burned or melted. So unless you fancy fumigating your workshop, don’t go near it.

Yes, it looks neat online, but it’s dangerous and completely unsuitable for the types of foam used in seating, bedding, and upholstery. Leave the hot wire for craft polystyrene — not your new sofa cushions.

The Old-School Electric Bread Knife Trick

Believe it or not, one of the best foam-cutting tools is something your nan probably used on a Sunday roast.

A cheap electric bread knife does a cracking job on upholstery foam — it cuts smoothly, leaves a clean edge, and doesn’t compress the foam like a manual knife sometimes can.

You’ll often find them at boot sales for a fiver, and they’ll handle most DIY cushion jobs no problem. The only catch? They’re not built for heavy use. Try to cut a dozen full sofa cushions and you’ll smell the motor before long.

👉 Perfect for hobbyists or one-off reupholstery jobs, but not for trade volume.

The Professional Options – Foam Cutters Built for the Job

For regular use, you’ll want something a bit more serious. There are a few electrical foam-cutting tools worth mentioning:

⚙️ Bosch Foam Cutter

Bosch make an excellent professional-grade foam cutter. It’s fast, accurate, and reliable – but it comes with a price tag to match.
Expect to pay over £600, and that’s before you buy the blade, blade guard, and glide (all sold separately).

Great if you’re cutting foam all day in a commercial setup — but frankly, overkill for most upholsterers and DIY users.

⚙️ KD-3 Electric Foam Cutter

Here’s the sweet spot for small-trade and professional upholsterers.

The KD-3 Electric Foam Cutter (supplied with an 8″ blade, guard & glide, £264.66) is a proper bit of kit made for upholstery work.

It uses one moving blade and one stationary blade, working together to give a clean, accurate cut right through soft or firm foam — ideal for seat cushions and bench pads.

Because only one blade moves, it keeps friction low and produces less drag or vibration than twin-reciprocating cutters, giving you that factory-smooth finish without the industrial price tag.

🧰 Manual Cutting – For Occasional or Precision Work

If you’re only cutting the odd seat cushion or back pad, a manual tool might be all you need.

At Foam4U we sell a Manual Foam Cutting Blade — a long, razor-sharp blade designed specifically for cutting foam cleanly and accurately (not a kitchen knife pretending to be one).

🔞 Over-18s only — it’s seriously sharp and not a toy.

Use a steady hand, mark your cuts with a felt-tip or tailor’s chalk, and guide the blade slowly through the foam without compressing it. Two light passes usually beat one heavy push.

🏭 How Foam4U Cuts Foam Professionally

When you order foam cut to size from us, we don’t use bread knives or bodged blades.

Our team uses industrial-grade equipment such as:

🧱 CNC foam cutting machines – for complex shapes and perfect repeat accuracy
🪚 NSL125 foam cutting bandsaw – for fast, straight, professional-grade cuts

That’s how we deliver the precise fit and finish you expect — whether it’s a campervan bench, boat seat, or sofa cushion replacement.

👉 O rder Foam Cut to Size from Foam4U

💡 Foam Cutting Tips from the Workshop

✅ Always mark your cutting line with a felt-tip or straight edge.
✅ Cut on a flat, stable surface with plenty of room.
✅ Avoid crushing the foam — let the blade glide through naturally.
✅ Replace or sharpen blades regularly.
✅ If the foam starts to tear, slow down — that’s your blade telling you it’s tired.

🚫 Common Mistakes to Avoid

❌ Using a hot wire – toxic and dangerous.
❌ Using scissors – leaves a jagged, uneven edge.
❌ Rushing the cut – foam fights back.
❌ Skipping a guide line – ends up looking like a banana.

🧵 The Bottom Line

Cutting upholstery foam isn’t rocket science — but it does take the right tools and a bit of patience. Start with a proper knife, keep your lines straight, and don’t fall for dodgy YouTube “hacks”.

Whether you’re a DIY upholsterer or a small-trade professional, Foam4U has the right gear, the knowledge, and the experience to help you get a factory-finish every time.