Methods and apparatus for providing an FFT engine using a reconfigurable single delay feedback architecture. In one aspect, an apparatus includes a radix-2 (R2) single delay feedback (SDF) stage that generates a radix-2 output and a radix-3 (R3) SDF stage that generates a radix-3 output. The apparatus also includes one or more radix-2 squared (R2^2) SDF stages that generate a radix-4 output. The apparatus further includes a controller that configures a sequence of radix stages selected from the R2, R3, and R2^2 stages based on an FFT point size to form an FFT engine. The FFT engine receives input samples at a first stage of the sequence and generate an FFT output result that is output from a last stage of the sequence. The sequence includes no more than one R3 stage.