Like maybe a website where I can enter a stanza of my poem in and check to see if it’s correct
No. Whether a line of poetry is acceptable in an iambic pentameter poem is not subject to a strict mathematical test. Most lines in iambic pentameter poems do not strictly meet the pattern of five “da-DUM’s”. Some of Robert Frost’s iambic pentamter poems don’t have even one line that meets that pattern exactly.
I suppose you could write software that would flag lines that seem to be a bit too far “outside the lines,” but you’d still have to use your human brain to decide for yourself, so why don’t you just do that in the first place? It’s really not freakin’ rocket science, child.