Count Down

Hi All

I have a chemical log which has an expiry date column showing various dates. I have also added another column called expiry countdown as I would like to be able to count down the number of days remaining for this product based on its expiry date and the date when I open the spreadsheet. My plan then is to add conditional formatting to highlight in colour when a product is getting close to expire.

does anyone know a way of being able to show days remaining?

copy attached.

Thanks for your help.

Phil