Four simple ways to know if you have the flu or just a cold

Blog Cold & flu

Easy Ways to Tell if You Have a Cold vs Flu

written by Maria Shikary Written by Maria Shikary
Maria Shikary

Maria Shikary

Dr. Shikary is a graduate of the Ohio State University School of Medicine, and trained in pediatrics at UCSF in San Francisco. She specializes in holistic/integrative medicine and nutrition.

Read more posts by this author.

December 2, 2021 Read Time - 6 minutes

What Is the Difference Between a Cold and the Flu?

While the flu and common cold are both respiratory illnesses, they are caused by different viruses. Although the common cold and flu are often lumped into the same diagnosis, it’s important to know whether you have one or the other, because there is a treatment available for the flu. 

Colds are much more common than the flu, with adults experiencing two to five colds on average per year. The flu is also extremely common, affecting about one out of five  Americans annually.

In general, the flu is worse than the common cold, with symptoms affecting the entire body. Individuals with colds tend to experience a runny or stuffy nose as their first symptom, while those with the flu often initially experience fever and fatigue.

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What Is the Common Cold?

The common cold is a viral infection that occurs in the upper respiratory tract, typically affecting the nose and throat. In most cases, cold symptoms are mild, and many types of viruses can cause the common cold.

Symptoms of the common cold typically appear one to three days after exposure. The common cold symptoms include:

  • Runny or stuffy nose
  • Sore throat
  • Nasal or sinus congestion
  • Cough
  • Body aches or a mild headache
  • Sneezing
  • Low fever (below 100.4° F)

What Is the Flu?

Influenza, commonly referred to as the flu, is a contagious respiratory illness caused by the influenza virus that often affects the nose, throat, and lungs. 

Unlike the common cold, influenza can cause mild to severe complications. The signs and symptoms of influenza typically come on suddenly. Some common flu symptoms include:

  • Fever
  • Cough
  • Sore throat
  • Runny or stuffy nose
  • Muscle or body aches
  • Headaches
  • Fatigue

Although a fever is a common symptom of the flu, not everyone with a flu will experience a fever.

Flu Symptoms vs. Cold Symptoms

Because colds and the flu share many of the same symptoms, it can be difficult to tell the difference between a cold and the flu based on symptoms alone. It can be helpful to ask yourself the following questions to help determine whether you have a common cold vs flu:

  • Did your symptoms start suddenly? Unlike the common cold, the flu starts suddenly. Often, people can give an exact time that it started.
  • Do you have a runny nose and sore throat? Common colds often start with these symptoms. Meanwhile, the flu tends to have more generalized symptoms that affect your whole body.
  • Do you have a fever higher than 100.4° F? Colds rarely cause high fevers. If you take your temperature and you’re experiencing fevers consistently above 100.4° F, you likely have the flu.
  • Do you have body aches and fatigue? The flu is a total body illness that causes inflammation in your muscles, leading to body aches and fatigue. The common cold, or “head cold,” usually only affects your head and upper chest.

Here is a comparison chart to help you easily find out whether you have a cold vs flu.

Symptom OnsetSymptoms can start gradually, not suddenlySymptoms begin suddenly
First SymptomsUsually runny nose & sore throatWhole body symptoms like body aches and fever
FeverUsually only a low grade fever, if any (below 100.4° F)Fever above 100.4° F
Body AchesMild, if anyMore severe body aches, muscle aches, and/or headaches
FatigueMild, if anyExtreme exhaustion that can begin suddenly

Do you want to know about the differences between a cold vs flu vs COVID? Read here to learn more about whether symptoms are a sign of a cold vs COVID.

Common Cold vs Flu: How the Diagnosis is Made

To really know whether you have the cold vs flu, a flu test can be done where a sample of mucus is taken from the very back of the nasal cavity. This test can show whether or not you have the flu. 

Because the common cold is caused by hundreds of different kinds of viruses, there is no easy test for it. Once a diagnosis is established, treatment decisions are made.

When Do I Call the Doctor with Flu or Cold Symptoms?

You should call your doctor with cold symptoms or flu symptoms if you’re experiencing:

  • Fever greater than 101.3° F or lasting 5 days or more
  • Shortness of breath, chest pain, or wheezing
  • Severe sinus pain, headache, or sore throat
  • Difficulty keeping fluids down

The Centers for Disease Control (CDC) recommends that people who are at high risk of serious complications seek medical attention for cold and flu symptoms. This includes people 65 years and older, people of any age with certain chronic medical conditions (such as asthma, diabetes, or heart disease), pregnant women, and children younger than 5 years of age.

Flu Treatment vs. Cold Treatment

Many people with the flu or cold symptoms experience mild illness and do not require medical care or antiviral medication. If you’re experiencing flu-like symptoms, stay home and avoid contact with other people.

Home remedies for cold and flu treatment include:

  • Staying hydrated and getting enough rest
  • Gargling warm salt water to soothe a sore throat
  • Adding moisture to the air with a vaporizer or humidifier
  • Using a saline spray or rinse to reduce congestion
  • Using over-the-counter cough and cold medications

If your symptoms worsen over time or you’re experiencing any of the symptoms mentioned above, contact your doctor. If your doctor determines that you have the flu, they may prescribe antiviral medication to treat your symptoms. Antiviral medications are most effective if they are taken within 48 hours of the first sign of the flu. 

If you have the flu and talk to your doctor within 72 hours of the start of your symptoms, they can prescribe Tamiflu (oseltamivir), which can help shorten the length of your symptoms.

  • Book on our free mobile app or website.

    Our doctors operate in all 50 states and same day appointments are available every 15 minutes.

  • See a doctor, get treatment and a prescription at your local pharmacy.

  • Use your health insurance just like you normally would to see your doctor.


Get Online Cold and Flu Treatment

Cold and flu symptoms can leave you feeling miserable, but you don’t have to leave your home to schedule an appointment with a licensed medical doctor. One of the online doctors at PlushCare can help you determine whether you have the cold vs flu and recommend the best treatment plan for your condition.

If you would like to speak to a doctor about your cold or flu symptoms, call or book online with PlushCare to set up a phone appointment with a top U.S. doctor today.

Read More About Cold vs Flu


PlushCare is dedicated to providing you with accurate and trustworthy health information.

Centers for Disease Control and Prevention. Cold Versus Flu. Accessed on March 24, 2021 at

Mayo Clinic. Common cold. Accessed on March 24, 2021 at

Centers for Disease Control and Prevention. Treatment: What You Need to Know. Accessed on March 24, 2021 at

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