Study reveals that the £5 note is dirtiest banknote in your wallet

A new study conducted by Merchant Machine looks into how fast banknotes move around the UK and US economy and the types of bacteria that get collected along the way.

May 2020: Research by Merchant Machine takes into consideration metrics such as the velocity of money in the UK and in the US (how fast different currencies move in the countries’ economies), the total number of spends of each banknote denomination and the number of hands it touches to find out just how many bacteria live on each note. You can view the full campaign here

With the COVID-19 outbreak, people have become more aware of the risks when it comes to personal interactions, social life and general hygiene. As a consequence, the number of cash transactions in the US and UK decreased significantly over the past year and more than a third of shoppers have been stopped from paying with cash, in a collective effort to limit the spread of the virus.

But how dirty is the cash we carry in our pockets?

Cash usage in the UK

Even though we are on the way to becoming a cashless society, according to the Access to Cash Review, 97% of Britons still carry cash in their pockets. The surveyed people stated that having cash at hand reassures them and provides ‘peace of mind’.

However, despite the number of people still carrying cash in their pockets, studies show that over the last ten years, cash usage in the UK has decreased drastically by 22%. This, along with the recent pandemic outbreak, small businesses have been going cashless for safety reasons and asking customers to pay with alternative methods such as debit and credit cards or e-wallets.

How dirty are the different UK notes?

This table shows more detailed information about money velocity, total number of spend and harmful bacteria found on each UK banknote.

Type of BanknoteEstimated VelocityNote Lifespan (years)Total Number of SpendsTotal Number of Hands TouchedTotal Types of Bacteria GatheredPotentially Harmful Bacteria per NoteBacteria
£510.18550.951153,0001,530Bacillus Pumilus, Coliforms, Listeria & Yeast
£102.10510.51133,000330Enterococcus, Listeria, Micrococcus & S. Aureus
£200.47209.41030,000300Bacillus, Coliforms, S. Aureus
£500.20204.0412,000120Bacillus, Micrococcus & S. aureus

According to the table above, £5 is the dirtiest UK banknote with an average of 50.9 number of transactions, resulting in almost 153,000 bacteria in its 5 years of circulation. Bacteria gathered on this type of note include Bacillus Pumilus, Coliforms, Listeria and Yeast. Coliform can be found in humans’ and animals’ waste and can cause symptoms including diarrhea, stomach cramps and vomiting. Listeria can be also found in human and animal feces and in soil.

The average £10 banknote is spent around 10.5 times in the course of its 5 year lifespan, gathering an average of 330 potentially harmful bacteria, including Listeria and Staphylococcus Aureus. The latter is known to be antibiotic resistant and it is considered extremely dangerous by the World Health Organisation (WHO). This bacteria can cause skin infections and badly affect blood and intestinal organs.

Due to smaller usage, £50 note is the ‘cleanest’ UK banknote, gathering on average only 120 potentially harmful bacteria, including Bacillus Pumillus, Micrococcus and Staphylococcus Aureus. Even being the ‘cleanest’, Bacillus Pumilus is particularly dangerous for children and can cause skin infections.  Furthermore, Micrococcus is a type of bacteria typically found in soil and water, and people with a weaker immune system are more likely to be affected by it.

The $10 bill is the dirtiest banknote in the US

According to a study, the US is the fifth cashless country in the world, followed by China and Australia.

Nowadays, in the US only 4% of transactions are made using cash; whilst the remaining 59% and 22% are made using credit cards and e-wallet, respectively.

From the table below it’s clear that the $5 and the $10 bills have the highest velocity and number of spends in an average of 5 years. This makes the $10 the dirtiest dollar bill with 16,344 types of bacteria accumulated in 5.3 years, 165 of which are potentially harmful.

Banknote TypeEstimated VelocityEstimated Note Lifespan (years)Total Number of SpendsTotal Number of Hands TouchedTotal Types of Bacteria GatheredPotentially Harmful Bacteria per Note

Why are we not cashless yet?

Although the prospect of a cashless society is very likely, some say that this could lead to the return of the barter, which would make it a lot harder for governments to collect taxes.

However, governments are not the only ones with an interest in cash remaining a form of transaction. Below are a few reasons why we shouldn’t go completely cashless:

  1. Cash is the most used method of payment amongst the poor: with nearly 1.3 million unbanked people in the UK, a lot of households can’t afford bank fees.
  1. Privacy: there is no doubt that cash transactions provide more privacy. Being able to choose how to pay is very important and should be people’s prerogative to decide how private they want to be when spending money.
  1. Identity theft: in 2018 there were more than 189,000 identity theft cases in the UK alone. Identity theft being strictly connected to the use of electronic payment methods, keeping cash an option could help limit the number of fraudulent transactions and contain the issue.

Ian Wright, CEO and founder of Merchant Machine comments:

“The pandemic completely revolutionised the way we live, interact and pay for things.

With so many businesses going cashless in the UK and all over the world, at Merchant Machine we want to provide SMEs with everything they need to know about card payments and payment options in the UK, in order to help them thriving in the world’s current economic landscape.’”

Notes to the Editor

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About Merchant Machine:

Merchant Machine provides an informative service about UK payment processing options. Their goal is to provide extensive guides with a unique UK perspective about all SMEs need to know about card payments. They cover topics such as card readers, payment gateways and virtual terminals.