Active and Passive Voice

An action of a subject, in relation to an object, is expressed in two ways. These two ways of expressing action of a subject are known as Voices.

     1. Active Voice
     2. Passive Voice


 I write a letter.                             (Active Voice)
 A letter is written by me.      (Passive Voice)

The structure of same sentence changes when expressed as Active Voice or Passive Voice. The meaning of a sentence, either expressed as Active Voice or Passive Voice, remains the same.

   Difference between Active Voice and Passive Voice.

The meaning or main idea of sentence, either expressed as Active Voice or Passive Voice does not change. The structure of a same sentence changes for Active Voice and Passive Voice.  We know that every sentence have a subject, a verb and an object. Subject is an agent who works on an object in a sentence. In the above example, “I” is the subject of the sentence that is doing some work on the object ‘letter’ in the same sentence.

To understand the difference in both voices, we should focus on the subject and the object of a sentence. In Active Voice, the subject acts upon the object. In Passive Voice, the object is acted upon by the subject. The meaning remains the same in both Voices but the sequence of the words (subject & object) changes. The sequence, of subject and object as in Active Voice, is reversed when it is expressed in Passive Voice. Read the following example for better understanding this difference.

Active Voice Passive Voice
I eat an apple. An apple is eaten by me.
He bought a car. A car was bought by him.

The sequence of the subject and the object of the sentence is reversed while converting the sentence from Active Voice to Passive Voice.

The structures of a same sentence, for both Voices, are as follows:

Active Voice: Subject + Verb + Object
Passive Voice: Object + Verb + Subject

   Change in the Verb of a Sentence for changing Voice of a sentence

Apart from reversing the sequence of subject and object, the form of the verb of sentence also changes in both Voices. In the above example, you can see the change in the main verb as well as auxiliary verb of same sentence in both Voices. The only form of verb used in Passive Voice is the 3rd form of Verb which is also called Past Participle. Hence, the rule for changing verb for converting a sentence from Active Voice into Passive Voice is to use only 3rd form of Verb in Passive Voice. For changing the auxiliary verb for converting a sentence from Active Voice into Passive Voice, there are rules varying for tenses. To learn these rules, read the rules for Tenses as given in the links on this page.  

   Basic Rules For Changing Active Voices Into Passive Voices

Rule No. 1. As mentioned earlier, the structure of sentence will be reversed in Passive Voice. The places of the Subject and the object will interchange. The subject will shift to the place of Object and the object will take the place of Subject in Passive Voice.

Active Voice: He buys a camera.
Passive Voice: A camera is bought by him.

Rule No. 2. Only Past Participle Form or 3rd form of verb (e.g. eaten etc) will always be used as main verb in Passive voices for all tenses. No other form of verb will be used as main verb. It can be seen in all the examples given on this page.

Rule No. 3. The word “by” will be used before subject in the Passive voice.

Active Voice: She drinks water.
Passive Voice: Water is drunk byher.

Rule No. 4. Other words such as ‘with’ or ‘to’ may also be used instead of word ‘by’ depending upon the subject of the sentence. These words are used in a very few cases. The word ‘by’ is used in the most cases.

Active Voice:: I know him.
Passive Voice: He is known to me.
Active Voice: Water fills a tub.
Passive Voice: A tub is filled with water.

Rule No. 5. The auxiliary verb will be changed in Passive Voice depending upon the tense of sentence in its Active Voice. There are rules for changing the auxiliary for each tense which can also be studied on this website.

Rule No. 6. Subject may not be always mentioned in Passive Voice. A passive voice sentence can be written without having subject, if it gives clear idea about the subject. Read the following examples.

Active Voice: Women are not treated as equals.
Passive Voice: Sugar is sold in kilograms.

Note: The above rules, except rule No. 5, are the basic rules for changing Active Voices into Passive Voice and apply to all type of sentences. The rule No. 5 is about the usage of auxiliary verbs in Passive Voices which differs for each tense of the sentence. These rules for each tense have also been explained on this website.