The interest rate on All Savers certificates will drop from 12.14 percent to 10.77 percent, effective Nov. 1.

Persons who wish to take advantage of the current rate must do so today or Saturday. The new rate will remain in effect until Thanksgiving.

All Savers certificates are tax exempt, one-year instruments that are fully insured by the U.S. government. Married couples filing jointly may take a one-time exclusion on their income taxes of $2,000 in interest earned on the certificates; individuals may exclude $1,000. To realize the maximum exclusion, a couple must invest $18,570 at the new rate; an individual, $9,285. There are penalties and a loss of tax exemption for premature withdrawal.

The interest rate on the certificates represents 70 percent of the average annual investment yield on one-year Treasury bills. Yesterday that yield fell from 17.34 to 15.39 percent.

The discount rate was 13.159 percent, down from 14.58 percent at the last auction Oct. 1. The coupon equivalent rate was 14.84 percent, compared with 16.65 percent at the last sale. The next auction is scheduled for Nov. 26.

Due to initial confusion over what rate was to be used, some financial institutions mistakenly issued certificates at 12.61 percent on Oct. 4 instead of 12.14 percent. The Internal Revenue Service ruled yesterday that certificates issued that day at 12.61 percent would qualify for a tax exemption.

The All Savers certificates first went on sale Oct. 1. During the first 20 days of this month federally chartered savings and loan associations drew in between $13 billion and 14 billion in All Savers funds, according to figures released yesterday by the Federal Home Loan Bank Board. That represents a net gain in deposits of $3 billion to $4 billion or about 25 percent "new money" not withdrawn from other accounts at S&Ls. It is also the first significant inflow into these institutions since last February.

For first three quarters of the year net deposits at savings and loans have grown 84 percent less than during the same period last year. Mortgage loans closed in September totaled $3.4 billion, the lowest volume since May 1980.

Banks and credit unions have not yet reported on sales of All Savers certificates.