As a nurse, it’s essential to be familiar with the different IV needle gauges and their corresponding colors. This article covers the most common ones you’ll encounter, including their flow rates and clinical uses. I also created a simple nursing mnemonic that can help you remember the main IV gauge colors and sizes.
Note: Most manufacturers follow a standard color-coding system, but if you’re outside the U.S., there may be some variation in these colors/size, so always verify your supplies.
What Is a Gauge?
The term “gauge” refers to the thickness or diameter of the needle or cannula. For instance, an 18-gauge IV is a relatively large IV catheter. IV catheters have needles, which helps the nurse penetrate and access the vein, and once in place, the needle is retracted, leaving behind a plastic cannula (a small straw-like part of the IV) that remains in the vein to administer fluids, medications, and so forth.
Important Rule of Thumb:
The lower the gauge number, the larger the diameter of the needle. For example, a 14-gauge is much larger than a 22- or 24-gauge.
When Gauge Size Matters
Choosing the correct gauge is vital for effective treatment. For example:
- If a patient requires a blood transfusion, avoid using a 24-gauge IV, as it could damage red blood cells.
- Larger sizes like 18-, 16-, or 14-gauge are preferred for rapid administration of fluids, medications, or blood, especially in emergencies or surgical settings (refer to your facility’s protocols for preferred IV sizes).
- Also, most IV catheters will list the flow rate, which may be a single number or a range. For example, a 14G IV catheter can typically deliver roughly 240 mL/min. This can also vary a bit sometimes, but it can help you visualize how the lower gauge numbers (14, 16, or 18 gauges) can allow much more fluids to travel through due to their larger needle/cannula sizes.
Common IV Gauge Sizes, Colors, Flow Rates, and Uses
Here’s a quick IV gauge color and size chart (always verify your facility’s protocols for proper IV gauge selection):
14-Gauge (Orange)
- Flow Rate: 240 mL/min
- Use: Emergency or traumatic situations requiring rapid administration of blood, medications, and fluids.
16-Gauge (Gray)
- Flow Rate: 180 mL/min
- Use: Surgery, trauma, ICU—situations needing fast fluid and medication delivery.
18-Gauge (Green)
- Flow Rate: 90 mL/min
- Use: Blood transfusions, rapid fluid administration, and some special procedures like CT with PE protocol (especially in the antecubital area).
20-Gauge (Pink)
- Flow Rate: 60 mL/min
- Use: IV fluids, medications; some protocols may allow blood transfusions—check institutional policy.
22-Gauge (Blue)
- Flow Rate: 36 mL/min
- Use: IV fluids, medications; ideal for elderly patients with fragile veins.
24-Gauge (Yellow)
- Flow Rate: 20 mL/min
- Use: Pediatric and elderly populations with small or delicate veins; suitable when 22-gauge cannot be used and high fluid volumes are not needed.
26-Gauge (Purple)
- Flow Rate: 13 mL/min
- Use: Neonates and pediatric patients; not used in adults. Ideal for very tiny, fragile, or damaged veins.
IV Gauge Sizes and Colors Mnemonic
After working with IV catheters daily, you’ll come to immediately know the different gauges and their colors. However, when you are first starting out, a mnemonic can help you remember the different gauges & their corresponding colors.
Here’s a mnemonic by Nurse Sarah:
A big 14 is orange like a tangerine, but a 16 gray is used in surgery all day;
Next is 18, which is lookin’ kinda green; but a 20 pink delivers meds without a blink;
Size 22 looks a little sad and blue, because the smaller vein fellas prefer the 24 yellas;
And a purple 26 can always work great, especially when your patient is a neonate!
IV Gauge Size and Color Practice Quiz
Ready to test your knowledge on the IV gauge sizes and colors? Take our free IV gauge size and color quiz.