How do you calculate car loan using bi-weekly payments with interest of 4.49% or which formula can be used?
Very carefully.
First, a 60-month loan is about 261 weeks, to wit: (EDATE(today(),60) - today())/7. That's
130.4 "biweeks".
A 60-month loan is always about 261 weeks (rounded up), regardless of the date of the loan. However, the number of weeks might depend on the date for loans that are not 1 to 5 years.
Second, most lenders determine the biweekly payment by calculating the monthly payment, then dividing by 2, to wit:
PMT(annualRate/12, #months, -loan)/2.
But according to one mortgage lender's online blog, some lenders determine it by calculating 12 times the monthly payment, then dividing by 26, to wit: 12*PMT(annualRate/12, #months, -loan)/26.
I'm not aware of any lender that truly amortizes over 26 weeks per year, to wit: PMT(annualRate/26, #biweeks, -loan).
Finally, the monthly rate is annualRate/12 in most countries.
But in some countries, it might be (1+annualRate)^(1/12)-1 (EU) or (1+annualRate/2)^(1/6)-1 (Canada).
Even in the EU and Canada, they might use annualRate/12 for non-mortgage loans. That is true of the UK, for example. I think it is true of Canada; but I have not been to get reliable confirmation.
In conclusion, according to one US online calculator (Navy Federal Credit Union), the biweekly payment for a $25,000 loan at 7% for 60 months is
$247.52, which can be calculated by:
=ROUNDUP(PMT(7%/12, 60,-25000)/2, 2)
Some lenders might simply round. Other lenders might round, round-up or round-down to the dollar or other increment.
Compare with the "true" amortized biweekly payment of
$227.56, which can be calculated by:
=ROUNDUP(PMT(7%/26, (EDATE(today(),60) - today())/14, -25000), 2)