Disclaimer: This information is not a substitute for professional medical advice, diagnosis or treatment.
Clinically reviewed by Dr James Harris, MBBS, FRACGP
AHPRA: MED0000981120
Not sure if you have a cold or the flu? While the symptoms can be similar, the flu typically comes on suddenly and causes more severe symptoms such as fever, fatigue, muscle aches and chills. A cold usually develops gradually and primarily affects the nose and throat.
Quick answer: Is it a cold or the flu?
If your symptoms started suddenly and you’ve been hit with fever, body aches, chills and extreme tiredness, you’re more likely to have the flu (influenza).
If your symptoms developed gradually and mainly involve a runny nose, congestion, sneezing and a sore throat, you’re more likely to have a common cold.
Because symptoms can overlap, speaking with a doctor can help you determine the most appropriate treatment and whether further testing is recommended.
What’s the difference between a cold and the flu?
A cold and the flu are both viral respiratory infections, but they’re caused by different viruses.
A common cold is usually caused by rhinoviruses and tends to be mild, affecting the nose and throat.
The flu is caused by influenza viruses and generally produces more severe symptoms that can leave you bedridden for several days and may lead to complications in some people.
Flu vs cold symptom comparison
| Symptom | Cold | Flu |
| Onset | Gradual | Sudden |
| Fever | Rare | Common |
| Chills | Rare | Common |
| Runny nose | Common | Sometimes |
| Sneezing | Common | Sometimes |
| Sore throat | Common | Common |
| Cough | Mild to moderate | Often severe |
| Body aches | Mild | Common |
| Headache | Uncommon | Common |
| Fatigue | Mild | Significant |
| Duration | Usually 7-10 days | Often 1-2 weeks |
What are the symptoms of a cold?
Common symptoms of a cold include:
- Runny nose
- Blocked nose
- Sneezing
- Sore throat
- Mild cough
- Mild fatigue
- Watery eyes
- Mild headache
Cold symptoms usually develop slowly over one to three days and improve within a week.
What are the symptoms of the flu?
Flu symptoms often appear suddenly and may include:
- Fever
- Chills
- Muscle aches
- Joint pain
- Severe fatigue
- Dry cough
- Headache
- Sore throat
- Loss of appetite
Many people describe the flu as feeling significantly worse than a cold because symptoms can affect the entire body.
How do I know if I have the flu or just a cold?
Ask yourself the following questions:
Did the symptoms come on suddenly?
A sudden onset often points to the flu.
Do I have a fever?
Fever is much more common with influenza than a cold.
Am I experiencing body aches and chills?
Muscle aches and chills are hallmark symptoms of the flu.
Am I exhausted?
If you’re struggling to get out of bed or perform normal activities, influenza may be the cause.
If you’re unsure, an online doctor can assess your symptoms and provide personalised advice.
Can a cold turn into the flu?
No. A cold cannot turn into the flu because they are caused by different viruses.
However, it is possible to catch the flu while recovering from a cold, or vice versa, particularly during winter when multiple respiratory viruses are circulating.
Why does the flu cause body aches?
When your body detects the influenza virus, it releases inflammatory chemicals that help fight infection.
This immune response can cause:
- Muscle pain
- Joint aches
- Fever
- Chills
- Fatigue
These symptoms are far less common with a typical cold.
How long does the flu last compared to a cold?
Common cold
Most people recover within:
- 7 to 10 days
Influenza
Symptoms often improve within:
- 1 to 2 weeks
However, fatigue and cough may persist for several weeks after the initial illness has resolved.
How are cold and flus treated?
Cold treatment
Most colds can be managed with:
- Rest
- Hydration
- Saline nasal sprays
- Throat lozenges
- Over-the-counter pain relief (when appropriate)
Flu treatment
Flu treatment may include:
- Rest and fluids
- Fever and pain management
- Medical assessment for high-risk individuals
- Antiviral medication in some cases if started early
A doctor can advise which treatment options may be appropriate for your circumstances.
When should you see a doctor for flu symptoms?
Speak with a doctor if you:
- Have difficulty breathing
- Develop chest pain
- Have a persistent high fever
- Are pregnant
- Have asthma, diabetes, heart disease or another chronic condition
- Are concerned about an elderly family member or young child
- Have symptoms that are worsening rather than improving
Telehealth can provide convenient access to medical advice without needing to attend a clinic while you’re unwell. If you develop chest pain or have difficulty breathing, please seek prompt in-person care.
How can I prevent colds and flu?
To reduce your risk of respiratory infections:
- Wash your hands regularly
- Cover coughs and sneezes
- Avoid close contact with people who are unwell
- Stay home when sick
- Get enough sleep
- Maintain a healthy lifestyle
- Consider annual flu vaccination if recommended for you
Frequently asked questions
Can you have the flu without a fever?
Yes. While fever is common with influenza, some people may experience flu without a noticeable fever.
Is a runny nose a sign of flu or cold?
A runny nose is more commonly associated with a cold, although it can occur with influenza.
What is the first symptom of the flu?
Many people experience sudden fatigue, body aches, chills or fever as the first signs of influenza.
Should I stay home with the flu?
Yes. Staying home can help you recover and reduce the spread of infection to others.
Can an online doctor help with flu symptoms?
Yes. An online doctor can assess your symptoms, provide medical advice, discuss treatment options and determine whether further investigation may be required.
Get expert medical advice from home
If you’re experiencing cold symptoms, flu-like illness, or you’re unsure what’s causing your symptoms, Doctors on Demand can connect you with an Australian-registered doctor from the comfort of home.
Our online doctors can assess your symptoms, provide personalised medical advice and help you determine the next steps for your care.
Book an online doctor appointment to speak with a doctor today.