In Jain Dharma, Navkārsi is not measured as a fixed amount of “bad karma reduced.” There is no exact numerical rule like “so many karmas are removed” after doing it.

Its spiritual benefit depends on:

• bhāva — your inner devotion and purity
• samyak upayog — right awareness and mindfulness
• ahiṃsā and restraint — whether it is done with discipline and respect
• absence of attachment and pride

What Navkārsi helps with

Navkārsi is a prayog of discipline and reverence, so it can help in:

• reducing pāp-bhāva through self-control
• increasing puṇya
• weakening attachment to food
• strengthening remembrance of the Navkār Mantra and the Pañca Paramesthī

Important point

In Jain view, karma is bound and shed by the state of the soul, not by a simple outside count. So the effect of Navkārsi is qualitative, not a fixed quantity.

Short answer

Navkārsi does not have a fixed “bad karma reduction” amount. Its merit is considered high when done with pure intention, humility, and full awareness.

If you want, I can also explain the Jain spiritual benefit of Navkārsi step by step.