CALCULATE - PRESENT SIMPLE
★ i calculate
★ you calculate
★ he/she/it calculates
★ we calculate
★ you calculate
★ they calculate
CALCULATE - PRESENT CONTINUOUS
★ i am calculating
★ you are calculating
★ he/she/it is calculating
★ we are calculating
★you are calculating
★ they are calculating
CALCULATE - PRESENT PERFECT
★ i have calculated
★ you have calculated
★ he/she/it has calculated
★ we have calculated
★ you have calculated
★ they have calculated
The Simple Past Tense, also called Simple Past or Preterite is a verb tense that is used to describe completed action happend in the past. It is the most basic form of past tense and it is formed by adding d, ed or ied to the base structure of the verb.
Present Continuous is a tense used for activities that are happening in the moment of speaking. It also can be used in a future aspect for future arrangements or plans. This tense is always used when you are describing a picture. The most used prepositions used with Present Continuous are AT THE MOMENT and NOW.
CALCULATE - PRESENT PERFECT CONTINUOUS
★ i have been calculating
★ you have been calculating
★ he/she/it has been calculating
★ we have been calculating
★ you have been calculating
★ they have been calculating
CALCULATE - PAST SIMPLE
★ i calculated
★ you calculated
★ he/she/it calculated
★ we calculated
★ you calculated
★ they calculated
CALCULATE - PAST CONTINUOUS
★ i was calculating
★ you were calculating
★ he/she/it was calculating
★ we were calculating
★ you were calculating
★ they were calculating
CALCULATE - PAST PERFECT
★ i had calculated
★ you had calculated
★ he/she/it had calculated
★ we had calculated
★ you had calculated
★ they had calculated
A transitive verb always has a noun that  receives the action of the verb, called the direct object.
An intransitive verb never has a direct or indirect object. Although an intransitive verb may be followed by an adverb or adverbial phrase, there is no object to receive its action
CALCULATE - PAST PERFECT CONTINUOUS
★ i had been calculating
★ you had been calculating
★ he/she/it had been calculating
★ we had been calculating
★ you had been calculating
★ they had been calculating
CALCULATE - FUTURE SIMPLE
★ i will calculate
★ you will calculate
★ he/she/it will calculate
★ we will calculate
★ you will calculate
★ they will calculate
CALCULATE - FUTURE CONTINUOUS
★ i will be calculating
★ you will be calculating
★ he/she/it will be calculating
★ we will be calculating
★ you will be calculating
★ they will be calculating
CALCULATE - FUTURE PERFECT
★ i will have calculated
★ you will have calculated
★ he/she/it will have calculated
★ we will have calculated
★ you will have calculated
★ they will have calculated
Present Simple is a tense used for talking about habits or activities that are constantly repeating. We also use Present Simple if we are talking about general thrust or facts about nature. This tense is also used in the Zero Conditional sentences and it is one of the most basic but also most important tenses of the English language. The most used prepositions with Present Simple are OFTEN, USUALLY, ALWAYS and many more.

CALCULATE - FUTURE PERFECT CONTINUOUS
★ i will have been calculating
★ you will have been calculating
★ he/she/it will have been calculating
★ we will have been calculating
★ you will have been calculating
★ they will have been calculating

Conjugation of verb calculate