Can a Paper Shredder Shred Cardboard for Compost?

Someone in r/composting asked for a good cardboard shredder back in 2022, because scissors had them worried about their wrists. The top reply came from an owner who'd been feeding boxes through an Amazon Basics 12-sheet for over seven years.

I've been using an Amazon basics 12 sheet shredder for over 7 years. It does regular corrugated cardboard boxes with no problem. It can even do double corrugated, but it will sound like it's dying.

u/viskoviskovisko, in r/composting

That's the whole answer, and the rest of these threads mostly add conditions to it. If you've got a stack of boxes and a cheap office shredder in mind, it'll chew single-wall cardboard, as long as you buy on sheet count, feed it strips and let it rest. One maker's manual says don't, and the warranty is where that bites.

What owners say it handles

A second 12-sheet owner bought theirs in 2018, and it still works as good as it did on day one. Their one instruction is to oil the blades, especially if cardboard is all you shred. The 12-sheet Amazon sells today is a newer model than either of theirs.

Up a size, an owner of an 18-sheet Aurora has fed thousands of feet of cardboard through it in almost four years. The limit they give is thickness, somewhere around three-eighths of an inch. Twice they've opened it up to blow the dust out, and now and then they run a lubricating sheet through. Otherwise it gets no attention at all.

At the top of the range, a household with a 24-sheet Amazon Basics has shredded fifty or sixty 55-gallon bags of cardboard in two years. The person who started that thread ran theirs for half an hour in a hot garage and it didn't overheat.

What the maker says

Black & Decker's manual for one of its home shredders lists what the machine isn't built for, and cardboard is on the list, alongside newspaper and adhesive labels. The same booklet's warranty doesn't cover damage from misuse.

If yours dies on a Costco box, the warranty is probably not on your side. One owner in a worm-composting thread bought the extended warranty on their new 18-sheet and wrote "challenge accepted".

Budget for it the way the owners do. A long-time composter in the first thread describes two schools of thought: a cheap, light unit you replace when it gives up, or a heavier machine that takes a bigger load and lasts. They'd started in the first camp and moved to the second after a couple of cheap ones.

How many sheets does a shredder need for cardboard?

Under 12, the threads turn into a failure log. A 2020 thread's title is its own verdict: a 6-sheet Amazon Basics can't handle half-inch cardboard for half an hour. One reply had burnt the motor on their 6-sheet and gone up to an 18.

The 8- and 9-sheet units in the same thread survive by being fed carefully. A 9-sheet Fellowes handles corrugated just fine, as long as it isn't run for half an hour straight. An 8-sheet takes cardboard cut into strips about half the width of a sheet of paper, and a full-width strip jams it.

At 12, the seven-year accounts above start, and so do the complaints about double-wall. A 12-sheet owner has to feed it smaller strips of the double-sided stuff or it bogs down.

Another, who'd just bought a 12, says they jumped the gun and would recommend a thicker capacity, though their forearm cramps from ripping boxes have gone.

At 18 and 24, the double-wall problem goes away. The composter who'd moved to a heavier machine says their Bonsaii 18-sheet takes double-ply corrugated without stalling.

A second owner of the same unit calls 18 sheets overkill unless your cardboard is really thick, and would go 12 or 14 for the light stuff.

The Amazon Basics 24-sheet takes two layers of standard corrugated at once, and a worm composter who'd owned the 8 and the 12 says the 24 shreds boxes they'd always had to recycle before.

Twelve sheets is the floor for single-wall boxes, and 18 or 24 if yours are double-wall. A few owners regret buying smaller, and nobody in these threads says they regret buying bigger.

Cross-cut, and how small to shred cardboard for compost

The pieces a cross-cut makes are a great size for composting, says the Bonsaii owner, who thinks micro-cut pieces would be too small and mat down when wet. The composter with the same machine agrees, and adds that micro-cut pieces involve a lot of dust.

The worm composter with the 24-sheet says micro-cut blades have to do more work on cardboard, so they overheat and wear out faster and shred slower. One dissenter runs a 10-sheet micro-cut Aurora and says it turns cardboard into mulch, and was worth what it cost. Cross-cut is the kind to buy unless you already own a micro-cut and want to try it first.

Feed it the way the owners do

The conditions are the same from every owner, whatever the size of the machine.

• Strips, not sheets. Cut the box down first. A box cutter gets it into strips that fit the slot, and one 24-sheet owner uses electric scissors to get big boxes down to shredding size without sore hands. A chicken keeper feeds seven or eight strips at a time, so the machine doesn't overheat and shut down.
• Pull double-wall apart. The porch owner of a 12-sheet de-laminates double corrugated by hand and feeds it as two sheets, and keeps needle-nose pliers to hand for jams. Someone with Costco boxes just pulls them in half and feeds the 12.
• Tape and labels off. Amazon's threaded tape is plastic. One owner put a lighter to it to check and it melted instantly. Labels and stickers won't decompose either, so they come off before the box goes in.
• Let it rest. The porch 12-sheet gets two tubs full before it needs a break, fewer in high summer. The 24-sheet's own cooldown, if it ever overheats, looks like fifty minutes to its owner.
• Oil it, and not from the kitchen. The 2018 owner says to oil the blades, but a reply in that thread warns that vegetable oil can harden on a blade, which they learned on a pair of loppers. The Aurora owner runs a lubricating sheet through, and an Amazon Basics owner recommends the cleaning sheets sold for the job. Shredder oil or the sheets, then.

Where the cheap ones are

A used one is the cheap way in, and plenty of these owners bought theirs that way. Thrift-store shredders go for pocket money, says a composter who shreds three to five boxes a day with one. Another has used a thrift-store shredder for a few years.

One found their 12-sheet on Craigslist. Another picked up an Aurora 20-sheet there, and it's been chewing through everything for over a year. A third got one free from a Buy Nothing group.

The lifespan question got asked outright in 2026, by someone eyeing a used 16-sheet on Marketplace and hoping for five years out of it. The answers were the 2018 owner above, someone five or six years into theirs, and a Costco 16-sheet bought about eight years ago and still running.

How to shred cardboard without a shredder

A good share of these threads thinks the machine is beside the point. The top answer in a "How do you shred cardboard" thread found tearing dry cardboard by hand tedious and painful, like juicing fruit by chewing. So they soaked big pieces in a plastic bin first, and most of the pain went away. A year later they were using their partner's shredder, which tells you something too.

Others hose the boxes down on the driveway and tear them when they're wet, or leave them in the rain until they rip like Kleenex. One reply advises against shredding at all: break the box into foot-wide pieces, lay them on the pile and let the heap soften them.

Soaking suits most hands and costs nothing. The composter who recommends it adds one exception: if a disability affects your hand strength or coordination, wet cardboard may not tear so easily either.

Buy on sheet count and buy cross-cut. For single-wall delivery boxes a few at a time, a 12-sheet does it, and a used one is the cheapest shredder you'll ever own. For double-wall, or a pile that comes back every week, go to the Bonsaii 18-sheet or the Amazon Basics 24-sheet. One new owner's first job was the box it came in. Tape off first.