How to Tell Between the Flu, a Cold, and COVID-19, According to a Doctor

When your nose starts running and your throat gets sore, it's clear you're coming down with something — the tricky part is figuring out what's causing it. In the midst of cold and flu season, a single coughing spell can prompt an arduous internet search about the difference between the flu, a common cold, and COVID-19 (and it doesn't help that they all have similar symptoms). Thankfully, there are some key ways to differentiate between each virus.

"Coronavirus and flu symptoms have significant overlap," says Sandra Kesh, MD, an infectious disease expert. "They both can cause fever, cough, breathing difficulties, fatigue, and many other symptoms." To know whether you're dealing with a cold, the flu, or COVID, it pays to know about the differences in symptom onset and duration. Certain symptoms can also give you a clue about what you might be dealing with (including loss of taste and smell).

Looking for more ways to tell each virus apart? Here's a breakdown of some of the most glaring differences between a cold, the flu, and COVID — plus expert-approved tips for prevention, and when to see a doctor.

Experts Featured in This Article

Sandra Kesh, MD, is a practicing infectious disease physician and the Chief of Population Health for Summit Health.

Flu vs. COVID Symptoms

The main difference between COVID and the flu is the onset and duration of symptoms.

As Dr. Kesh notes, both COVID and the flu share several symptoms, including fever, cough, shortness of breath, muscle pain, runny or stuffy nose, and fatigue. However, the flu generally has a quicker onset, overwhelming those infected within one to four days, according to the Centers for Disease Control and Prevention (CDC). COVID symptoms, on the other hand, appear two to 14 days after exposure to the virus. The duration of symptoms also differs. While flu symptoms can last anywhere from three days to two weeks, COVID symptoms generally last the full two weeks (and upwards of six weeks for more severe infections, per to Hopkins Medicine).

Cold vs. COVID Symptoms

The main difference between COVID and a common cold is the severity and duration of symptoms.

Of these respiratory infections, the common cold is by far the most moderate virus (although it's still highly unpleasant). Cold symptoms are usually milder than COVID and appear more gradually than the flu, peaking about two to three days post-exposure. The common cold is often also short-lived: symptoms generally last about seven days, as opposed to COVID and flu symptoms, which can last for two weeks.

Cold vs. Flu vs. COVID Symptoms

The main differences between COVID, the flu, and common cold symptoms include sneezing, fever, shortness of breath, and loss of taste and smell.

To better understand the differences in symptoms between the flu, the common cold, and COVID, here's a quick breakdown of which symptoms are most common for which virus, as informed by Dr. Kesh and the Mayo Clinic:

When to See a Doctor

If you're experiencing flu-like symptoms and/or believe you have been exposed to COVID, purchase an at-home COVID test from your local drug store or visit your medical provider for a diagnosis. If you're elderly, pregnant, dealing with a chronic medical condition, or caring for a young child with flu-like or COVID symptoms, Dr. Kesh advises you to seek medical care immediately. To protect yourself and your community from COVID (as well as the cold and flu), wash your hands properly and regularly, keep surfaces in your home clean, and stay home when you're sick.

— Additional reporting by Angelica Wilson, Alexis Jones, and Chandler Plante

Dominique Michelle Astorino is a former PS contributor.

Angelica Wilson is a former associate fitness editor for PS. She's a tall, plus-size yoga instructor who's a been a K-pop fan since '09. It's a unique combo, but it works. She enjoys sharing what brings her joy so that others can potentially find joy in her interests as well. In case you were wondering, Angelica is a Leo sun and Leo rising with an Aquarius moon.

Alexis Jones is the senior health and fitness editor at PS. Her passions and areas of expertise include women's health and fitness, mental health, racial and ethnic disparities in healthcare, and chronic conditions. Prior to joining PS, she was the senior editor at Health magazine. Her other bylines can be found at Women's Health, Prevention, Marie Claire, and more.

Chandler Plante is an assistant editor for PS Health and Fitness. She has over four years of professional journalism experience, previously working as an editorial assistant for People magazine and contributing to Ladygunn, Millie, and Bustle Digital Group. In her free time, she enjoys finding new ways to rock her 18(!) different eye patches, and making videos about chronic illness, beauty, and disability.