For past and present, there are 2 non-complex tenses + 6 complex tenses (using auxiliary or helping verbs).

To these, we can add 4 "modal tenses" for the future (using the modal auxiliary verbs will/shall).

This makes a total of 12 tenses in the active voice.

Another 12 tenses are available in the passive voice (though 4 are rarely used).

So now we have 24 tenses, as you see in the table below:

24 tensespastpresentfuture
activenon-complex tensespast simplepresent simplefuture simple
complex tensespast perfectpresent perfectfuture perfect
past continuouspresent continuousfuture continuous
past perfect continuouspresent perfect continuousfuture perfect continuous
passivepast simplepresent simplefuture simple
past perfectpresent perfectfuture perfect
past continuouspresent continuousfuture continuous
past perfect continuouspresent perfect continuousfuture perfect continuous

The basic structure of a positive or affirmative sentence is:

subject + auxiliary +  main verb

The following table shows the 12 active tenses for the regular verb work  in the affirmative or positive:

12 active tenses (work)structurepastpresentfuture
auxiliarymain verb
simplenormal  I workedI workI will work
intensivedobaseI did workI do work 
continuousbepresent participle -ingI was workingI am workingI will be working
perfecthavepast participleI had workedI have workedI will have worked
continuous perfecthave beenpresent participle -ingI had been workingI have been workingI will have been working

Notes : An auxiliary verb is actually used in all tenses. In the present simple and past simple tenses, the auxiliary verb is usually suppressed for the affirmative, but it does exist for intensification. It is also of course always used in forming questions and negatives.

Technically, there are no  future tenses in English. The word will  is a modal auxiliary verb and future tenses are sometimes called "modal tenses". The examples are included here for convenience and comparison.

sources : Original Link