Maturity amount calculation for recurring deposit where interest is compounded quarterly, using the function FV:
Maturity amount = FV( (Rate of interest)/4, 4 * (Period in years), - (Value of each instlament) * (3 + (Rate of interest) / 2))
For example, an RD of Rs. 5000 each month for a period of 1.5 years at interest 7.5% p.a. compounded quarterly yields on maturity and amount of:
FV(7.5%/4, 4 * 1.5, -5000 * (3 + (7.5%/2))) = Rs. 95,504.78
The above formula is a general formula and individual banks might use a slightly different formula. For example, the Indian Banks' Association uses the following formula for computing the maturity value where interest is compounded quarterly (Source: http://www.iba.org.in/formula.asp):
Maturity amount = ((Value of each instlament) * ((1+i)^n-1))/(1-(1+i)^(-1/3)),
where i = (Rate of interest) /4
and n = number of quarters.
Hence, taking the same example of RD of Rs. 5000 each month for a period of 1.5 years at interest 7.5% p.a. compounded quarterly, the maturity value, according to this formula is:
((5000) * ((1+(7.5%/4))^6-1))/(1-(1+(7.5%/4))^(-1/3)) = Rs. 95502.35
Extending the formula to other compounding periods:
For Monthly compounding:
Maturity amount = ((Value of each instlament) * ((1+i)^n-1))/(1-(1+i)^(-1))
where i = (Rate of interest)/12
and n = number of months.
For half-yearly compounding:
Maturity amount = ((Value of each instlament) * ((1+i)^n-1))/(1-(1+i)^(-1/6))
where i = (Rate of interest)/2
and n = number of years * 2.
The above formula is a general formula and individual banks might use a slightly different formula. For example, the Indian Banks' Association uses the following formula for computing the maturity value where interest is compounded quarterly (Source: http://www.iba.org.in/formula.asp):
Maturity amount = ((Value of each instlament) * ((1+i)^n-1))/(1-(1+i)^(-1/3)),
where i = (Rate of interest) /4
and n = number of quarters.
Hence, taking the same example of RD of Rs. 5000 each month for a period of 1.5 years at interest 7.5% p.a. compounded quarterly, the maturity value, according to this formula is:
((5000) * ((1+(7.5%/4))^6-1))/(1-(1+(7.5%/4))^(-1/3)) = Rs. 95502.35
Extending the formula to other compounding periods:
For Monthly compounding:
Maturity amount = ((Value of each instlament) * ((1+i)^n-1))/(1-(1+i)^(-1))
where i = (Rate of interest)/12
and n = number of months.
For half-yearly compounding:
Maturity amount = ((Value of each instlament) * ((1+i)^n-1))/(1-(1+i)^(-1/6))
where i = (Rate of interest)/2
and n = number of years * 2.
Download the following app on your android phone to compute the maturity amount for fixed and recurring deposits: http://goo.gl/olkbN. You can also do these calculations online at https://bank-interest.multisocialshare.com/