In apparatus for correcting an error in a codeword according to a syndrome, means is provided for transforming the computed syndrome through a succession of syndrome sequences or values and for counting the number of syndrome sequences in the succession. The values of each syndrome sequence are sensed to detect a distinct predetermined value and the bit in error is located from the count of the number of syndrome sequences and inverted for correction. The preferred embodiment uses a shortened BoseChaudhuri codeword and uses a linear feedback shift register to transform the syndrome values.