To fry a turkey, you generally need enough oil to completely submerge the bird in the fryer pot without causing overflow. A practical way to measure this is to place the uncooked turkey in the empty fryer pot, fill the pot with water until the turkey is just covered or near the maximum fill line, then remove the turkey and mark the water level. Drain the water and refill the pot with oil up to the marked level. In terms of quantity:

• For a typical 30-quart pot, about 3 gallons of oil are used.
• For a 32-quart pot, about 3 1/3 gallons are recommended.
• For turkeys, oil quantities scale with weight, for example:
  • A 9-pound turkey requires 3 to 4 gallons of oil.
  • A 13-pound turkey requires 4 to 5 gallons.
  • A 15 to 22-pound turkey requires about 5 to 6 gallons.

The key is to ensure the turkey is fully submerged but without risking oil overflow when the turkey is lowered in. Also, keep safety in mind, use oils with high smoke points like peanut oil, and always fry outdoors away from structures.

So, to sum up, the amount of oil needed to fry a turkey depends on the turkey's size and the fryer pot volume, typically ranging from about 3 to 6 gallons. Measure with water first for accuracy before adding oil.