Tenses in the English language

Sometimes in English, a tense is formed with additional words and not just conjugated verb forms. You could say that there are four forms of a verb:

1. present
2. past (regular or irregular)
3. 3rd form (or past participle)
4. Gerund (-ing or continuous form)

As the gerund form is so regular, most grammar books list only the other three forms.
However, there are more than four tenses because tenses are made from forms using other words

1. will
2. when (implying the future)
3. if (implying the future)

The future tenses in English really show how these additional words are used to form the sense of time we call the tense. We consider all these verbal forms to be English tenses. Most of these are actually combinations of the past and present tenses together with auxiliaries and aspect.
The consistency with which the future is expressed in English using the auxiliaries shall/will and the perfect and the progressive (continuous), etc., are achieved by the use of the auxiliaries BE and HAVE is such that we usually speak about all these versatile verbal forms as though they were tenses.
We could say that there are many more tenses in English, but since the tenses are often formed with additional words, it is hard to tell exactly how many there are. It always depends on how we approach the problem and there are many ways to approach this problem of English tenses.