To determine the proper needle length for your patients’ vaccinations, the first things you need to consider are the route of injection — whether it is intramuscular (IM) or subcutaneous (SC) — and the anatomic site of the injection. For infants and children, the patient's age must be considered, and for adults, the patient's weight may need to be taken into account.

Below is a summary of the guidance on choosing the proper needle length for IM and SC injections based on CDC’s General Recommendations on Immunization: Recommendations of the Advisory Committee on Immunization Practices (pages 13–16).

For infants and children

Intramuscular injections: Injection site and needle size

  • Newborns (0–28 days): Anterolateral thigh muscle, ⅝" needle, 22–25 gauge.

    Note: For neonates (first 28 days of life) and preterm infants, a ⅝" needle usually is adequate if the skin is stretched flat between the thumb and forefinger and the needle is inserted at a 90-degree angle to the skin.
  • Infants (1–12 months): Anterolateral thigh muscle, 1" needle, 22–25 gauge
  • Toddlers (1–2 years) have two options for injection site and needle length:
    • Anterolateral thigh muscle, 1–1¼" needle, 22–25 gauge
    • Deltoid muscle, if muscle mass adequate: 5/8"–1" needle, 22–25 gauge
  • Children (3–18 years) have two options for injection site and needle length:
    • Deltoid muscle, ⅝–1" needle, 22-25 gauge
    • Anterolateral thigh muscle, 1–1¼" needle, 22–25 gauge

Subcutaneous injections: Injection site and needle size

  • Age 0 to 12 months: Fatty tissue overlying the anterolateral thigh muscle, ⅝" needle, 23–25 gauge
  • Age 12 months and older: Fatty tissue overlying the triceps or the anterolateral thigh  muscle, ⅝" needle, 23–25 gauge

For adults

Intramuscular injections

The deltoid muscle is most often used as the site for IM injections in adults: Needle length is usually 1–1½", 22–25 gauge, but a longer or shorter needle may be needed depending on the patient's weight.

According to CDC’s General Recommendations on Immunization (page 16), you should choose needle length based on the weight of your adult patients as follows:

  • Adults weighing less than 130 lbs (60 kg): ⅝" needle is sufficient for IM injection in the deltoid muscle only if the subcutaneous tissue is not bunched and the injection is made at a 90-degree angle
  • Adults weighing 130–152 lbs (60–70 kg): 1" needle is sufficient
  • Women weighing 152–200 lbs (70–90 kg) and men weighing 152–260 lbs (70–118 kg): 1–1½" needle is recommended
  • Women weighing more than 200 lbs (90 kg) or men weighing more than 260 lbs (118 kg): 1½" needle is recommended

An alternate site for IM injection in adults is the anterolateral thigh muscle (use 1–1 ½” needle, 22–25 gauge).

Subcutaneous injections

Fatty tissue overlying the triceps muscle: ⅝" needle, 23–25 gauge

Materials in this section are updated as new information and vaccines become available. The Vaccine Education Center staff regularly reviews materials for accuracy.

You should not consider the information in this site to be specific, professional medical advice for your personal health or for your family's personal health. You should not use it to replace any relationship with a physician or other qualified healthcare professional. For medical concerns, including decisions about vaccinations, medications and other treatments, you should always consult your physician or, in serious cases, seek immediate assistance from emergency personnel.