We know the power of Panchadasi mantra.

क ए ई ल ह्रीं। ka e ī la hrīṁ |

ह स क ह ल ह्रीं। ha sa ka ha la hrīṁ |

स क ल ह्रीं॥ sa ka la hrīṁ ||

It is said that one repetition of Panchadasi mantra is equivalent to three repetitions of Turya Gāyatri mantra. Following is the Turya Gāyatri mantra.

1) ॐ भूर्भुवः स्वः॥ om bhūrbhuvaḥ svaḥ ||

2) ॐ तत्सवितुर्वरेण्यं। om tat saviturvareṇyaṁ |

3) भर्गो देवस्य धीमही। bhargo devasya dhīmahī |

4) धियो यो नः प्रचोदयात्॥ dhiyo yo naḥ pracodayāt ||

5) परोरजसे सावदोम्॥ parorajase sāvadom || ||

Out of the five lines above, first line is vyāhṛti-s. Second, third and fourth lines together form the Gāyatri mantra. These lines are called first pada (pada means step), second pada and third pada. In Turya Gāyatri, fourth pada is added at the end of third pada which is the fifth line above.

परोरजसे सावदोम्॥ parorajase sāvadom ||

Parorajas means beyond the world and this can be explained as Turya state where in all the three normal states of consciousness exist. Turya state is also called witnessing consciousness. This is also explained in Bṛhadāraṇyaka Upaniṣad.

First pada or vāgbhavakūṭa:

Tat – refers to Brahman (That) and this is represented by the letter ka क.

Savitur varenya is split into two savitṛ and varenya represented by the next letter ए e. Savitṛ refers to the creative aspect of Brahman and varenya means the best and adorable.

Bhargo devasya dhīmahī is represented by the letter ई ī. This pada is split into bharga + devasya + dhī + mahī. Bharga means the innermost (Self) of everything. Devasya means belonging to Brahman. Dhī means to meditate. The last part of this pada is taken to the next letter ल la.

Mahī of the previous letter and the third pada dhiyo yo na pracodayāt represent the letter ल la. Mahi means mahat or great. Dhiyo yo na pracodayāt also represent the letter ल la and is in the form prayer. This is addressed to Shiva with a prayer to inspire our mind to move towards which is beyond contemplation.

Parorajase sāvadom represent ह्रीं hrīm. Parorajase sāvadom mean beyond the word, the Supreme Light, Prakāśa, Shiva. This is beyond three gunas, the Absolute Consciousness whose abode in the heart (the Self within).

The five letters in this kūṭa represent the five primary elements of creation.

Second pada or Kāmarājakūṭa:

That is the Self or Brahman. Savitṛ vareṇyaṁ here represents two letters ह ha and स sa. ha refers to sun and sa refers to moon. These two letters represent the Divine Essence of Shiva and Śakti. These two letters also mean the Supreme Self and the individual self.

Bhargo devasya represent the letter क ka and denotes Shiva. dhī represents ह ha and referring to Shiva, which is considered as the seed letter for the next word mahi, which means the earth. Mahi refers to ल la. 

Parorajase sāvadom represent ह्रीं hrīṁ. Parorajase sāvadom mean beyond the word, the Supreme Light, Prakāśa, Shiva. This is beyond three guṇa-s, the Absolute Consciousness whose abode in the heart (the Self within).

Third pada or Śaktikūṭa:

Tat Savitṛ vareṇyaṁ is represented by the first letter of this kūṭa स sa, indicating the individual soul.

Bhargo devasya dhī is represented by the letter क ka and denotes Shiva. Mahi refers to ल la, the seed letter for earth mahi.

Parorajase sāvadom represent ह्रीं hrīṁ. Parorajase sāvadom mean beyond the word, the Supreme Light, Prakāśa, Shiva. This is beyond three guṇa-s, the Absolute Consciousness whose abode in the heart (the Self within).

Thus, one repetition of Pañcadaśī mantra is equivalent to three repetitions of Turya Gāyatri. It is generally said that no mantra should be repeated more than the number of repetitions of Gāyatri mantra.

Other Important Articles:

Pancadasi Mantra - पञ्चदशी मन्त्र - Part 1

Panchadasi Mantra Explained - Part 2

Panchadasi The Supreme Mantra - Part 3 

Lalithambigai's Panchadasi Mantra 

An analysis of Panchadasi Mantras