The dirtiest spot on your desk (it’s not where you’d think)

Now, I don’t mean to alarm you. But…

Your office desk contains 400 times more germs than a toilet seat. Pretty shocking, isn’t it? – especially given the importance of keeping hands and surfaces as clean as possible to reduce the spread of COVID-19.

The good news is that if you regularly wipe down your worktop, the potential for bacteria to multiply in your home, or in a shared office space, decreases drastically. But which elusive corner of your desk is harboring the most germs? 

Turns out, the answer is more straightforward than you might think. It’s your smartphone, covered in 25,127 microbes per square inch compared to just 1,201 on a toilet seat (…yuck).  

Smartphones have been identified in ongoing research conducted by Dr. Chuck Gerba (aptly nicknamed Dr. Germ), a professor of microbiology at the University of Arizona, as being absolute germ traps for harmful viruses such as E.coli, streptococcus (strep throat), and MRSA.

“We touch more surfaces than any other generation in history, from ATM machines to self-checkout counters”, Gerba told USA Today back in 2019 – and with 80% of all infections spreading through our hands (according to the CDC), it’s a good idea to be mindful about how to stop nasty bugs getting passed onto our friends and co-workers as more of us return to the office.

Deal with the dirt

In the case of your smartphone, the problem is easy to solve by giving it a gentle wipe with a 70% isopropyl alcohol or Clorox cloth to prevent bacteria from accumulating. Dr. Gerba cleans his own mobile device twice a day for good measure!

However, the mini microbial feast happening on your desk doesn’t begin and end here. Desks have become dumping grounds for our daily lives since working from home became the norm – strewn with crumbs, mail, sticky notes, and even more bacteria than found in offices, says the professor.

Not exactly habits we want to be taking back into the workplace again. So, here’s some other top dirty desk spots to look out for, and how to zap proliferating pathogens fast to prevent from getting sick or losing time and productivity.


Yep, the desktop itself. Specifically, the exact spot where you lay your hand to rest. Here is where all the germs that you’ve picked up during the day party together – and given that the average working adult touches as many as 30 objects per minute, this area has been consistently condemned as the dirtiest spot on the desk next to cell phones.

The key to limiting your risk of contracting one of the many bugs that multiply here – 10 million, in fact – is to avoid touching your face and mouth. Easier said than done, seeing as we naturally do this 16 times every hour, but definitely something that could be limited. 

Better yet, use hand sanitizer regularly – it kills 97% of the bacteria on your hands, leading to a cleaner office all round.

Computer mouse and keyboard

Two more obvious culprits for harboring dirt. If you guessed the mouse or keyboard, then (congratulations!) they’re positively riddled with germs as well, concealing no less than 1676 and 3,295 microbes per square inch. Being grimier than most objects on your desk, they take a bit of extra cleaning – as much to protect the keys and sensors as to stay healthy.

To crack down on the dirt, switch off and disconnect all power sources. Then, flip your keyboard upside down to shake out any debris, and give both the keyboard and mouse a good wipe with a microfiber cloth. Use compressed air to clean out the crevices, apply some alcohol solution as a finishing touch, and boom: mouse and keyboard will be spick and span.

Coffee mug

Another top contender. See that abandoned coffee mug pushed to the side of your desk (out of sight and out of mind)? It’s a breeding ground for malicious microorganisms. The University of Arizona found that 90% of all office cups are contaminated by germs, with 20% carrying faecal matter. That’s poop, to you – and it was found on clean as well as dirty mugs.

Pre-pandemic, shared kitchen sponges were hardly ever washed, meaning that we were essentially just wiping bacteria onto our cups. Well, no more. Take your own mug home to put through the dishwasher, advises Gerba, or invest in a small office cup washer for quick cleaning!

Personal items    

Succulent lovers, it’s bad news for you. The depersonalization of the desk space is set to become our new reality, says Nabil Sabet from M Moser workplace design associates, and it’s all because of how much trinkets, knickknacks, and other unnecessary pieces of décor and personal memorabilia can gather dirt – becoming hotspots for unwelcome germs.

It leaves one thing left to answer. Until the day that desk rotation becomes normal, the solution is to pack anything that belongs at home – books, photocopies of documents, makeup, the lot – away, to keep your own desk spot refreshingly clear of any clutter that could attract bacteria. Heck, you might get it shaping up to be as clean as a toilet seat!