The quick answer
One lakh is 100,000. One crore is 10,000,000. Dividing 10,000,000 by 100,000 gives 100, so 1 crore = 100 lakhs.
Convert crores to lakhs
Multiply the number of crores by 100. For example, 2.5 crores × 100 = 250 lakhs. For the reverse calculation, divide the number of lakhs by 100: 75 lakhs = 0.75 crore.
Keep the units visible
Write crore or lakh after the number until you finish the calculation. In Indian digit grouping, one crore is written 1,00,00,000 and one lakh is 1,00,000. The comma pattern changes; the underlying quantity does not.