How Long Does a Fever Last?
Quick Answer
2–3 days for most viral infections. Bacterial fevers may persist 5–7 days without antibiotics. Seek medical attention if fever exceeds 103°F or lasts more than 3 days.
Typical Duration
Quick Answer
A fever from a common viral infection typically lasts 2–3 days before breaking on its own. Bacterial infections can cause fevers lasting 5–7 days or longer without antibiotic treatment. Most fevers in healthy adults are self-limiting and resolve as the immune system fights off the underlying cause.
Fever Duration by Cause
| Cause | Typical Duration | Notes |
|---|---|---|
| Common cold | 1–3 days | Low-grade, often under 101°F |
| Influenza (flu) | 3–5 days | Can spike to 104°F |
| COVID-19 | 2–7 days | Variable, may return |
| Strep throat | 3–5 days untreated | Resolves in 24–48 hrs with antibiotics |
| Urinary tract infection | 2–4 days | Clears quickly with antibiotics |
| Ear infection | 2–3 days | Common in children |
| Pneumonia | 5–10 days | Depends on bacterial vs viral |
| Stomach virus | 1–3 days | Usually short-lived |
Fever Stages
- Rising phase: Body temperature climbs, you feel cold and shiver as your body generates heat
- Plateau phase: Temperature stabilizes at its elevated level, you feel hot and flushed
- Breaking phase: Temperature drops back to normal, sweating occurs as the body releases excess heat
Children vs. Adults
Children tend to run higher fevers than adults, often reaching 103–104°F even with minor infections. Their fevers may also spike and drop more dramatically throughout the day. Febrile seizures can occur in children 6 months to 5 years old but are generally not harmful.
Adults typically run lower fevers (100.4–102°F) and can tolerate them better. However, adults over 65 may not mount strong fevers, so even low-grade fever in elderly patients can signal a serious infection.
When a Fever Is Dangerous
Seek immediate medical attention if:
- Temperature exceeds 103°F (39.4°C) in adults
- Fever lasts more than 3 days without improvement
- Infant under 3 months has any fever (100.4°F or higher)
- Child 3–6 months has fever above 102°F
- Accompanied by stiff neck, confusion, or difficulty breathing
- Severe headache, rash, or persistent vomiting
- Recent surgery or immunocompromised status
Treatment Options
Over-the-counter medications:
- Acetaminophen (Tylenol): 500–1000 mg every 4–6 hours for adults
- Ibuprofen (Advil/Motrin): 200–400 mg every 4–6 hours for adults
- Aspirin: Adults only (never give to children due to Reye's syndrome risk)
Home care:
- Stay hydrated with water, broth, and electrolyte drinks
- Rest and allow the body to fight the infection
- Use lightweight clothing and blankets
- Take lukewarm (not cold) baths
- Monitor temperature every 4–6 hours
Should You Always Reduce a Fever?
Not necessarily. Fever is the body's natural defense mechanism that helps fight infection by making the environment less hospitable to pathogens. Many doctors recommend treating a fever only when it causes discomfort or exceeds 102°F, rather than aggressively reducing every low-grade temperature elevation.
Tips for Faster Recovery
- Hydrate aggressively — fever increases fluid loss through sweating and increased metabolic rate
- Sleep as much as possible — the immune system is most active during sleep
- Eat when hungry — light, nutritious foods like soup, toast, and fruit support recovery
- Avoid alcohol and caffeine — both contribute to dehydration
- Stay home — rest prevents spreading illness and speeds recovery