Writing quantities in lakhs is a frequent source of misunderstanding. The problem usually arises when putting the amount in words, even when the numerical representation is apparent, for instance, if you need to write Rs 10,00,000 (10 lakh). Is "Lakh" or "Lac" more appropriate?
The bank OF INDIA' target='_blank' title='reserve bank of india-Latest Updates, Photos, Videos are a click away, CLICK NOW'>reserve bank of india (RBI) claims that "lakh" is the proper word. The RBI standards make it very clear that the word "lakh" must be used in english while writing checks. This phrase may be seen on the RBI website and all official bank checks. 'Lac' is not a term used in formal financial vocabulary.
Although using "Lac" rather than "Lakh" is unlikely to result in a check being canceled, it is nevertheless advised to use the latter. 'Lac' is sometimes mistaken for a material used for varnishing or sealing, which can lead to misunderstanding. Although 'Lac' can be used to refer to 'Lakh' in common speech, 'Lakh' is the preferred and appropriate term in banking.
Therefore, while writing 'Lakh' on a check, it's best to prevent any such problems.