Flaccid vs erect penis size. Why measurements differ

Many men notice a significant difference between their flaccid and erect penis size. This is completely normal and is influenced by anatomy, blood flow, temperature, and individual physiology.

Understanding this difference is important, particularly for men considering penis enlargement surgery or penis filler treatments.

Why Flaccid Size Varies So Much

The flaccid penis is highly responsive to external factors, including:

• Temperature

• Stress and anxiety

• Physical activity

• Blood circulation

This is why flaccid size can change throughout the day. Cold environments and stress can cause the penis to retract, while warmth and relaxation can increase flaccid hang.

Some men are “growers,” meaning their flaccid penis is smaller but expands significantly when erect. Others are “showers,” with less variation between states.

Erect Size Is More Consistent

Erect size is determined primarily by internal erectile tissue and blood flow. Unlike flaccid size, erect length and girth tend to remain consistent under similar conditions.

For this reason, urologists place greater emphasis on erect measurements when assessing anatomy and treatment suitability.

How Measurements Are Taken Clinically

At Moorgate Andrology:

• Flaccid measurements are taken before surgery or fillers

• Post-operative comparisons focus on flaccid length and girth

• Erect measurements may be discussed but are not always required

👉 Learn how measurements are taken:
https://knowledgebase.moorgateandrology.co.uk/measuring-your-penis-when-it-is-erect-length-girth

How Surgery and Fillers Affect Size

Penis enlargement surgery can increase:

• Flaccid length (ligament release)

• Permanent girth (fat transfer)

👉 https://moorgateandrology.co.uk/penis-enlargement-surgery/

Penis fillers increase:

• Girth (temporary, 12–24 months)

• Flaccid hang may appear improved due to reduced retraction

👉 https://moorgateandrology.co.uk/penis-fillers/

Erect length increase following surgery is usually modest, and fillers do not increase erect length.

Final Thoughts

Differences between flaccid and erect size are normal. If concerns persist, a medical consultation is the best way to determine whether treatment is appropriate or necessary.