How many irregular verbs in english?

It is not an easy question to answer! 

Anyhow there is an "Irregular Verb Dictionary" that sorts out more than 470 verbs. Just check the following link to have a look:

http://www.englishpage.com/irregularverbs/irregularverbs.html

Apologized for the answer, I do not know the answer Leave for the professionals.

http://www.englishpage.com/irregularverbs/irregularverbs.html

370 irregular verbs used in modern English

Agree with your specialties answers. Thanks

If we exclude prefixed and compounded derivatives, there are 250 or so. (Quirk et al)