“To” is usually the correct preposition with the verb “to contribute”. In spoken English, people also use “toward” or “towards” with very little change in meaning.
“To” and “Toward(s)” have the same meaning in this context and they mean “in the direct of”.
He contributes to the team greatly.
I contribute to Vincent de Paul every month.
“To” is the best preposition to go with the verb “to contribute”. “To” is necessary to connect the subject of the sentence(the object being contributed) with the object of the sentence(the receiver of the contribution).
I contribute to the community.
In the example above, the subject of the sentence is “I” and the object is “the community”.
We often use a direct object and an indirect object and we need to use “to” between them to form a sentence.
I contribute my time to the community.
In the above example, “my time” is the direct object and “the community” is the indirect object. You can read more about direct and indirect objects here.
In my experience “contribute toward ” or “contribute towards’ ‘ are used more in the situation of money but the subtle difference is to highlight the good deed that someone is doing. The contribution is often modest and using toward(s) helps to emphasize that there were limited resources available.
I want to contribute towards the rent. Please let me.
Ah he is not that bad. He always wants to contribute toward the dinner in some manner.
It is important to note that you can always use “to” in place of “toward” for a more neutral meaning. “Towards” is more often used in spoken English and there is often more emphasis placed on “towards” than there would be on “to” in the same sentence.
It is also important to note that “toward” is preferred by American English speakers and “towards” is preferred in British English.
Contribute + No Preposition
We use “contribute” without a preposition when the receiver of the contribution has been previously mentioned or implied.
The NGO is going to contribute food.
In this example, the receiver could be refugees that have been previously mentioned.
The preposition “for” is not commonly used with the verb ”to contribute”. It is tempting to use “for” to show the reason why something happens but we always need “contribute to + receiver”.
He contributes so much to the team.
The preposition “in” is not commonly used with the verb ”to contribute”. It is tempting to use “in” to show the context something happens in but we always need “contribute to + receiver”.
He contributes to science in the field of biology.
Contribution TO or For or Of
“Contribution” is the noun form of the verb”to contribute”. That means that you are talking about the specific thing contributed such as money, food or clothes.
We still use “to” with “contribution” when we want to connect the subject of the sentence(the object being contributed) with the object of the sentence(the receiver of the contribution).
He made a contribution to the Green Party.
The only difference with the word “contribution” is that we can also use “of” to show the exact details of the contribution.
He made a contribution of £1,000 to the Green Party.
Notice that we still need “to” to show who the receiver of the contribution is. We also don’t use the preposition “for” with “contribution”.
The verb “to contribute” and the noun “contribution” both take the preposition “to” to connect the receiver of the action with the donor.