Answer
In the absence of a stipulated rate, the legal rate of interest for a loan or forbearance of money, goods, or credit is six percent (6%) per annum. This rate took effect on 1 July 2013 under Bangko Sentral ng Pilipinas Monetary Board Circular No. 799, as applied by the Supreme Court in Nacar v. Gallery Frames (G.R. No. 189871, 2013); for periods before that date the rate was twelve percent (12%).
No interest is due unless it has been expressly stipulated in writing (Civil Code Article 1956). Although the interest ceilings of the Usury Law were suspended by Central Bank Circular No. 905 (1982), the suspension did not legalize excessive rates — courts continue to strike down interest that is iniquitous or unconscionable as contrary to morals (Articles 1229 and 1306).