Avery labels and cards in the US are mostly based on the 8.5" x 11" standard sizes. A4 paper sizes are used in the UK, Germany, France, and other regions of the world.
If you have an A4-sized Avery product that you want to print, you can find the template on the website it originated from using one of the links above. Avery templates are available on each country's specific website.
If you're looking for a product in the US that is similar in size, remember that A4 paper is slightly thinner and longer (8-1/4" x 11-3/4") than the US standard of 8.5" x 11".
A5 paper (5-7/8" x 8-1/4") is half the size of A4, so Avery Note Cards are a similar size since each card is a half-sheet (there are two note cards on a page). When open, each note card is 5-1/2" x 8-1/2", but when folded, they are 4-1/4" x 5-1/2", which is closer to A6 size.
A6 paper (4-1/8" x 5-7/8") is half the size of A5, so is similar to our postcards (4" x 6" or 4-1/4" x 5-1/2") or our labels on 4x6 sheets.
Note: Remember to change your printer settings if you are printing a product in a different size than usual.