Cold vs Flu: How to Tell the Difference
Learn the key differences between cold and flu symptoms, how to treat each one effectively, and when to seek medical help.
Common Cold Symptoms
A cold usually comes on gradually over 2 to 3 days. The hallmark symptoms are a runny or blocked nose, sneezing, a sore throat, and a mild cough. You might feel slightly unwell but can usually carry on with daily activities. Colds are caused by over 200 different viruses, with rhinovirus being the most common. Adults typically get a few colds a year, and children get noticeably more. You should begin to feel better in about 1 to 2 weeks, and symptoms can last longer in young children. The mucus may change from clear to yellow or green as your immune system fights the virus — this is normal and doesn't mean you need antibiotics.
Flu Symptoms
Flu tends to come on suddenly — often within hours. Key symptoms include a high fever (38°C+), severe body aches and muscle pain, extreme tiredness that may keep you in bed, headache, dry cough, and chills. Unlike a cold, flu usually makes you feel too unwell to carry on as normal. The flu is caused by influenza viruses (types A and B) and is most common between December and March in the UK. Recovery typically takes 1–2 weeks, though fatigue can linger for several weeks. The flu can be serious, especially for the elderly, pregnant women, and people with chronic conditions.
Key Differences at a Glance
The main difference is speed and severity: flu hits harder and faster. Flu almost always causes a high fever; colds rarely do. Flu causes significant body aches; cold aches are mild. Flu causes extreme fatigue that confines you to bed; cold tiredness is manageable. Sneezing and a runny nose are prominent in colds but less so with flu. A dry, painful cough is more characteristic of flu, while cold coughs tend to be productive. Flu is more likely to lead to serious complications like pneumonia, especially in at-risk groups. If you're unsure, think: 'Could I go to work?' If yes, it's probably a cold. If absolutely not, it might be flu.
Treatment and When to See a Doctor
Both colds and flu are treated with rest, plenty of fluids, and over-the-counter remedies. Paracetamol or ibuprofen can reduce fever and ease aches. Honey and lemon in warm water soothes sore throats (honey is not suitable for children under 1). Decongestant sprays can help a blocked nose but shouldn't be used for more than 7 days. Call 999 or go to A&E if you get sudden chest pain, severe difficulty breathing — gasping, choking, or unable to get words out — or you start coughing up blood. Contact NHS 111 or ask for an urgent GP appointment if you feel very unwell or short of breath, your symptoms have not improved after 7 days, or you are in an at-risk group: 65 or over, pregnant or recently given birth, have a long-term condition affecting your heart, lungs, liver, kidneys, brain or nerves, have a weakened immune system, or you are worried about a baby's or child's symptoms. If you are in an at-risk group, get in touch when the flu starts rather than waiting for it to get worse — they can assess whether antiviral treatment is appropriate for you.
- respiratory
- infections
- winter health
Sources and further reading
This page was written from the following published guidance. All links checked 26 August 2026.