Answer

There is no fixed conversion like “1 Mangalashtak = how many Namokars.”

Explanation

• Mangalashtak is a separate prayer/stotra, usually made of 8 auspicious verses.
• Namokar Mantra is a different and independent mantra.
• So they are not traditionally measured against each other in a standard counting ratio.

Spiritual Understanding

In Jain practice, both are sacred in their own way:

• Namokar Mantra is for bowing with devotion to the Arihants, Siddhas, Acharyas, Upadhyayas, and Sadhus.
• Mangalashtak is recited for auspiciousness and reverence.

Takeaway

If you mean a chanting count, the safe answer is: no standard one-to-one equivalence exists.