How Long Am I Contagious?
Typical contagious periods and typical time off work or school for common conditions, drawn from HSE guidance.
Typical ranges, not medical advice. Your GP assesses your individual case. This tool does not take symptoms and does not diagnose — it shows published guidance for a condition you select.
Select a condition to see its typical contagious period and typical time off work or school, based on HSE guidance.
Why contagious periods matter
Most common infections spread before or after the days you feel worst — flu and COVID-19 are contagious before symptoms start, and the vomiting bug remains infectious for a full 48 hours after the last symptom. Going back too early is how one sick day becomes a sick office.
The timings above are the HSE's published typical ranges. Individual cases vary with age, immunity and severity, and workplaces, schools and creches can set their own exclusion policies — when in doubt, check with them, or ask a GP.
Need a sick cert while you are off?
If your employer needs a medical certificate — and statutory sick pay requires one from day one — a GP consultation takes minutes and can be done from your bed. You can also estimate what you're owed with our sick pay calculator.
This page provides general information from published HSE guidance, with sources cited per condition. It is not medical advice, does not assess symptoms and does not diagnose any condition. If you are worried about symptoms, talk to a GP; for emergencies call 999 or 112.