The NHS COVID-19 app calculates how long you need to self-isolate for, depending on the reason you're self-isolating.
If you’ve had a ‘close contact’ alert
If you're self-isolating because the app has alerted you that you've been near someone who has tested positive for coronavirus (COVID-19), it will use the date of the last ‘close contact’ you had with the person to calculate how long you need to self-isolate.
You need to self-isolate for 10 full days from the date you were last in contact with the person; the ‘encounter date’. This means that if you were in close contact with someone who tested positive for coronavirus on the 1st of the month, you would need to self-isolate up to and including the 11th of that month.
If you have symptoms
If you're self-isolating because you have coronavirus (COVID-19) symptoms, and have entered these into the app, the app will use the day you reported you first had symptoms to calculate how long you need to self-isolate. When you enter symptoms in the app it will ask you for the date they first started; the ‘symptoms onset date’.
You need to self-isolate for 10 full days from the date you first had symptoms of coronavirus. This means that if you first had symptoms on the 1st of the month, you would need to self-isolate up to and including the 11th of that month.
If you said that you cannot remember when your symptoms started, the app will calculate your ‘symptoms onset date’ as 2 days before you reported symptoms into the app.
If you’ve had a positive test result
If you report symptoms and book a coronavirus test through the app, the app will automatically be updated with your test result. Your isolation period is calculated using the date you first had symptoms, so if you test positive, this date will not change.
If you tested positive, but did not enter symptoms or book your test through the app, you may be able to link your test result to the app using a code. In this case, the app uses the date the code was generated to set your self-isolation countdown timer. This is because it does not have any other information about your test or when your symptoms started. The date the code was generated is counted as ‘Day 0’ in your 10 day countdown. This means that if your test code was generated on the 1st of the month, you would need to self-isolate up to and including the 11th of that month.
If you test positive you'll also be contacted by the wider NHS Test and Trace or NHS Wales Test, Trace, Protect service. Contact tracers will use the date the test was taken or the date you confirm your symptoms started to calculate your isolation period. If the date your test was taken is not the same as the date your code was generated, then this isolation period may differ from the isolation period on the app. Read more about what do if the self-isolation countdown on your app is different from the advice you’ve been given by NHS Test and Trace or NHS Wales Test, Trace, Protect.
If you’ve had a negative test result
If you test negative, the countdown timer may clear or reset. However, in some cases, you may need to continue to self-isolate even if you've received a negative test result. If this is the case, your self-isolation countdown timer will reflect this. Read more about why you may need to continue to self-isolate after testing negative.