Oh, how we love our numbers. Our fitness tracker tells us we’ve walked 9,874 steps today. Only 126 more and we will have reached 10,000 step perfection. You don’t really need another pair of black leggings but hey, how can you resist a 40% off sale? And as you stare at the gas station pump’s scrolling numbers, you root for round-number totals and maybe keep squeezing the pump until you get there.

Maybe we think those numbers offer precisely measured information, but take another look. Those cut-and-dried figures are often full of emotion and clues to complicated behavior.

For one thing, decades of research have found that we love round numbers so much that we often regulate our behavior to achieve them.

Like those who wear fitness trackers, professional baseball players and high school SAT takers also exert more effort when their performance falls just short of a round number rather than just above, according to a Psychological Science study.

In real estate, sellers who use round numbers receive lower but quicker offers, as many buyers assume that round number prices communicate an eagerness to sell, according to a National Bureau of Economic Research study.

And don’t be surprised if a $15 crab cake appetizer makes your mouth water more than one for $14.99. When deciding whether to order food at a restaurant — or any product whose quality you cannot judge before purchase — you may unconsciously use the roundedness of the price as a proxy for quality and nonround prices as a stand-in for value, according to a Management Science study.


“That’s why you don’t see a Chanel bag for $4,999.99,” said Olga Shurchkov, a behavioral economist at Wellesley College.

Said differently, people react to not only what a number counts but also how they feel about its roundness.

“Numbers have a language of their own. People think that numbers are used for quantitative information only, but they often indicate qualitative information, as well,” said Gaurav Jain, a Rensselaer Polytechnic Institute marketing assistant professor who co-wrote a new study published in Organizational Behavior and Human Decision Processes.

In his research involving hundreds of participants, Jain found that people take longer to process non-round numbers. As they work to make sense of such a number, they tend to compare it to an ideal round number for the given situation.

Jain offers the following example: If a vaccine for a deadly disease is 91.27% effective, health officials seeking to encourage vaccinations might want to communicate the rounded percentage of 90% to the public, even though the nonrounded percentage promises a better health outcome. This is because a vaccine that’s 91.27% effective falls short of the ideal — a vaccine with 100% effectiveness. The person making the comparison is then disappointed by the available vaccine and, as such, can be less likely to act by getting vaccinated, Jain said. In contrast, the rounded statistic of 90% invites no comparison. Since 90% is a robust percentage, Jain said that a person feels good about it, which will make them more likely to get vaccinated.

“We don’t pause or hiccup when we encounter round numbers, but we find nonround numbers jarring,” said Shurchkov, who was not involved in Jain’s recent study. “A round number is easier to grasp than a nonround number.”


Behavioral economists have known for decades that the words in a message highlight either positive or negative attributes, which in turn affect human behavior. For example, whether beef is labeled as 80% lean or 20% fat influences consumers’ purchasing decisions, even though both refer to the same product, according to an often-cited 1988 Journal of Consumer Research study. Consumers wanting healthier options were more likely to select 80% lean beef, whereas those seeking tastier options were more likely to select 20% fat beef, as fat is associated with taste, according to the study.

Jain is not the first to identify that people have feelings about round numbers.

In recent years, store checkout clerks have begun asking customers if they would like to round up their bills to make a charitable donation. That is because customers respond more favorably to requests to round up a bill than to a flat donation request, even when the amount requested is identical, according to a 2018 Journal of Consumer Psychology study.

“If they ask you to donate 67 cents to a charity, you might think, ‘Eh, no, not today, thank you.’ But by asking if you want to round up, they’re helping you achieve a goal of having a round bill,” said Shurchkov of humans’ soft spot for round numbers.

This has implications for not only public policy experts and marketers but also individuals.

“Every citizen is a consumer, even if they don’t shop,” Jain said. “They consume information and ideas that are thrown about. If they understand the tools and tactics of marketers, they’ll make far better consumption decisions.”

Of that, and our love of round numbers, perhaps we can be close to 100% sure.