In many Jain communities, the common tap-count is:

• 4 biyasana (biashna) = 2 ekasana = 1 upvas

For ambil / ayambil, the count can vary by tradition and community, so there is no single universal conversion. In some places, 2 ayambil are taken as roughly equal to 1 ekasana, but this is not fixed everywhere.

So, the safest short answer is:

1 upvas ≈ 2 ekasana ≈ 4 biyasana Ayambil conversion depends on local tradition.

If you want, I can also give you a full Jain fasting conversion chart in a simple table.