MEASUREMENT
The Erection Hardness Scale. Four grades, one honest signal.
Short answer: the Erection Hardness Score (EHS) is a simple 1 to 4 scale used by doctors and researchers. Grade 1 means larger but not hard, grade 2 hard but not enough for penetration, grade 3 hard enough but not fully rigid, and grade 4 fully hard and rigid. Grades 3 to 4 are considered functional; consistent scores of 2 or below suggest erectile dysfunction.
The four grades
Grade 1: penis is larger but not hard. Grade 2: hard but not hard enough for penetration. Grade 3: hard enough for penetration but not completely hard. Grade 4: completely hard and fully rigid. Some versions add grade 0 for no enlargement at all.
Where it comes from
The scale was validated by Mulhall and colleagues (Journal of Sexual Medicine, 2007) and is widely used in clinical trials of ED treatments. Its strength is simplicity: one question, answered right after the event, with good correlation to longer questionnaires.
EHS vs IIEF-5
The IIEF-5 (SHIM) is a five-question survey covering the past six months, scored from 5 to 25, and is the standard ED screening tool. EHS measures a single erection. They're complementary: IIEF-5 gives the big picture, EHS lets you track night-to-night variation.
Why grade 3 vs 4 matters
Studies show men and partners report notably higher satisfaction at grade 4 than grade 3, even though both allow penetration. A slide from 4 to 3 over months is often the first change men notice, sometimes years before outright ED, which makes it a useful early signal for vascular health.
Using it to track yourself
Rate morning erections and sexual erections separately. Log the score alongside sleep, alcohol, stress and exercise. Over a few weeks, patterns appear: a lower score after drinking, a higher one after good sleep. Bring the trend to a doctor if your average drops.
WHAT YOU GET
Built for signal, not noise.
Grades 1 to 4
Grade 4 is fully rigid, 3 to 4 is functional.
Clinically validated
Used in trials of ED treatments since 2007.
Built for tracking
One quick rating makes trends visible.
READ NEXT
Keep going.
QUESTIONS
What people ask before signing up.
What is a normal erection hardness score?
Grades 3 and 4 are considered normal and functional. Grade 4 is fully rigid.
Does EHS grade 3 mean I have ED?
Not necessarily. Grade 3 allows penetration. A consistent shift from 4 to 3 is worth watching but isn't a diagnosis.
What's the difference between EHS and IIEF-5?
EHS rates a single erection on a 1 to 4 scale. IIEF-5 is a five-question survey of the last six months.
Can I use the erection hardness scale at home?
Yes. It's designed for self-rating, and tracking it over time gives the most useful information.
EARLY ACCESS
A score is useful. A trend is better.
Owain tracks morning and sexual erection quality daily. Free on iPhone.
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