To calculate the size and location of defects in a weld using ToFD, the following steps are typically performed:

1. The distance between the transducers (d) and the angle of incidence (θ) are measured.
2. The time it takes for the ultrasonic pulse to travel between the transducers and reflect off a flaw is measured (t).
3. The velocity of the ultrasonic wave in the material is determined (v).
4. The size of the defect is calculated using the following formula:

Size of defect = (d * t * sin(θ)) / (2 * v)

1. The location of the defect is determined by measuring the time delay between the transmitted pulse and the reflected signal.