An in-memory computing method and apparatus, adapted for a processor to perform MAC operations on a memory, are provided. In the method, a format of binary data of weights is transformed from a floating-point format into a quantized format by truncating at least a portion of fraction bits of the binary data and calculating complements of remaining bits, and programming the transformed binary data into cells of the memory. A tuning procedure is performed by iteratively inputting binary data of input signals into the memory, integrating outputs of the memory, and adjusting the weights programmed to the cells based on the integrated outputs. The binary data of the weights is reshaped based on a probability of reducing bits with a value of one in the binary data of each weight. The tuning procedure is repeated until an end condition is met.