Scansion

>>9656203
The little red x's are things I got wrong per line. The first column is stress followed by number of feet, then meter.

>>9656185
There's some flexibility in how you stress monosyllables.

The problem is stress is pretty subjective. And of course while reading a poem aloud one doesn't fully intone every stressed syllable, you have to strike a balance between attention to meter and the natural flow of spoken language, lest you sound like a loon.

Personally I tend to downplay the importance of function words (especially determiners) in stress. For example, in the first line, I would rather transpose the stress from 'my' onto 'salt', because it sounds awkward to put the stress in a noun phrase on the possessive rather than the word that actually means something. However, it could go either way, and I don't think an online grading tool can ever be really accurate unless someone goes through every poem by hand and marks a bunch of different possibilities.

Christmas Eve, and twelve of the clock.
“Now they are all on their knees,”
An elder said as we sat in a flock
By the embers in hearthside ease.

Ok, this is just bullshit. There is no way I'll accept that the first line is in iambic tetrameter.