Erection quality

The Erection Hardness Scale (EHS): How to Rate Your Own Erections

August 4, 2026 · 9 min read

The Erection Hardness Score (EHS) is a four-point scale used in sexual medicine to rate how firm an erection is: grade 1 means the penis is larger but not hard, grade 2 means hard but not hard enough for penetration, grade 3 means hard enough for penetration but not completely rigid, and grade 4 means completely hard and fully rigid. It was validated as a research measure by Mulhall and colleagues in a 2007 paper in the Journal of Sexual Medicine, and it has survived because it is short enough to actually use. One question, four answers. That is the whole instrument.

Below: how to place yourself on it, what one score is worth (less than you might hope), and what a series over months is worth (considerably more).

The four grades, described so you can place yourself

The wording below stays close to the scale as it is used in research; the added notes are there to make self-scoring less ambiguous, not to redefine the grades.

Grade 1 — larger, but not hard

The penis enlarges and fills somewhat, but there is no rigidity. Squeezed lightly, it gives way completely. This is tumescence without firmness.

Grade 2 — hard, but not hard enough for penetration

There is clear firmness. The penis holds some of its own weight but bends or buckles under light pressure, and penetration is not realistic. Men often describe this as “most of the way there and then it stalls.”

Grade 3 — hard enough for penetration, but not fully rigid

Penetration is possible. The erection works, but it is not at its maximum. There is still some give when you press, and it may need ongoing stimulation to hold. Many men spend a fair number of their sexual encounters here without thinking anything of it.

Grade 4 — completely hard and fully rigid

Full rigidity. The penis is firm all the way through, holds its own angle without help, and does not buckle under pressure. This is the ceiling of the scale — there is no grade 5, and no version of “harder than fully hard.”

Some versions of the scale add a grade 0: no enlargement at all. If that is where you are, the rest of this article is not the right tool. Talk to a doctor.

A note on honest scoring. The most common self-scoring error is grade inflation: rating a 3 as a 4 because the encounter went fine. The scale asks about rigidity, not about whether sex worked or how it felt. Score the physical state, not the evening.

What one score tells you: almost nothing

Erection firmness is not a stable trait. It moves with sleep, alcohol, stress, the time of day, how long it has been, how relaxed you are with the person you are with, and a dozen things you will never isolate. A single grade 3 after a five-hour night and two beers is not data about your body. It is data about that Tuesday.

Most content on this topic gets this wrong in both directions — the reassuring version (“everyone has off days, ignore it”) and the alarming version (“a grade 3 is an early warning sign”). Both read one data point as if it meant something. Measures with this much day-to-day variation only become readable as a series.

Why a series over months is worth something

The reason to write it down is unglamorous: memory is bad at slow change. If your typical erection quality drifts from a grade 4 to a grade 3 over eight months, you will almost certainly not notice it happening. You will notice it one day as a conclusion — “this has gotten worse” — without any idea when it started or by how much. That conclusion arrives with no evidence attached, which makes it both hard to act on and easy to catastrophize.

A log addresses exactly that one problem. It does not make anything better by itself. It makes change visible.

Practical version, if you want to do it:

Score the same situation. Partnered sex, solo, or on waking — pick one and stay with it. Mixing contexts makes the series unreadable.
Score soon after, not at the end of the week. Retrospective ratings drift toward whatever mood you are in when you write them.
Expect scatter. A series of 4, 3, 4, 4, 3, 4 is not a downward trend. It is a normal month.
Read months, not weeks. Look at whether the average of the last four weeks differs from the average three months ago. Anything shorter is noise.

This is the reasoning behind the hardness self-rating in the PhalluShape progress log, which sits next to the length measurement rather than replacing it: firmness and size are separate things that happen to be tracked the same way. If your interest is on the size side, the percentile calculator and our piece on what the average actually is are the more useful starting points — for context, Veale and colleagues put the mean erect length at 5.17 inches (13.12 cm) in their 2015 BJU International review, a pooled analysis of 17 studies, though the erect-length figure itself rests on a much smaller subset of those men than the review’s 15,521 total.

Morning erections: a signal, not a diagnosis

Nighttime erections are not sexual. Sleep-lab research going back decades has found that healthy men have several erection episodes per night, tied to REM sleep. Morning wood is usually just the last of those, still present because you woke during or shortly after a REM phase.

That is why their absence on any given morning means so little. Whether you notice one depends on which sleep stage your alarm caught you in, how fragmented your night was, and whether you woke up gradually or abruptly. Men who sleep badly notice fewer of them for reasons that have nothing to do with their erectile function.

What is worth paying attention to is a sustained change: nighttime erections that were reliably there and have been consistently absent for weeks or months. Because these erections happen without arousal, their disappearance can point toward a physical rather than a psychological cause — which is genuinely useful information, but it is information for a doctor to interpret, not a conclusion you can reach at home. Take it as a reason to make an appointment, not as a self-diagnosis.

What moves erection hardness in ordinary life

The honest framing here is associative. The factors below are consistently linked to erection quality in observational research; that is not the same as proving that changing one of them will change your score, and the size of any individual effect is unknown.

Sleep. Short sleep is one of the few variables where men reliably report a same-week difference in their own logs. In a 2011 JAMA paper, Leproult and Van Cauter restricted 10 young men to five hours of sleep for one week and found measurable physiological changes after just one week — ten men is a very small study, and the outcome was not erection firmness.

Alcohol. The acute effect is well documented and most men have observed it directly. Heavier long-term use is separately associated with worse erectile function in population studies.

Smoking. Erections depend on blood flow, and smoking is one of the strongest modifiable factors associated with erectile difficulty in the epidemiological literature. In the Massachusetts Male Aging Study (Feldman et al., 1994, 1,290 men aged 40 to 70), 52 percent reported some degree of erectile difficulty, and smoking was among the factors associated with the more severe categories.

Movement and body weight. Both are associated with erectile function in observational data, through the same vascular and metabolic pathways. Causation is genuinely tangled here — men who move more differ from men who move less in many other ways too.

Stress and mental load. Hard to quantify and therefore under-represented in the numbers, but it shows up clearly in individual logs: bad weeks at work often produce a visible dip. It is also the factor most likely to create a self-reinforcing loop, where one disappointing evening shapes the anxiety that shapes the next one.

The pelvic floor connection

The pelvic floor muscles are involved in maintaining an erection — they contribute to trapping blood in the erectile tissue once an erection has formed. This is one of the few areas in this field with a randomised trial behind it, rather than none. A 2004 randomized controlled trial by Dorey and colleagues in the British Journal of General Practice randomised 55 men to either pelvic floor muscle exercises or lifestyle advice alone, and reported better erectile function in the exercise group. It is a small trial, and improvement was measured by self-report — but it is a real trial, which is more than most claims in this space can offer.

If your logged scores are drifting and you want something concrete to do, that is where we would point you first: pelvic floor exercises for men, which explains how to locate the muscles and what a sane weekly load looks like.

When self-assessment is no longer enough

Logging is a tool for noticing. It is not a substitute for a diagnosis, and there are situations where you should stop tracking and make an appointment:

A sustained decline. Your typical score has dropped by a grade and stayed there for two to three months.
A sudden change. Firmness that changed abruptly rather than gradually.
Nighttime and morning erections that have consistently stopped.
Any pain, curvature that is new or worsening, or an erection that will not subside — the last one is a medical emergency; go to an emergency room.

There is one more reason to take a persistent change seriously, and it has nothing to do with sex. A 2014 systematic review by Gandaglia and colleagues in European Urology summarized a large body of evidence linking erectile difficulty with cardiovascular disease, with erectile symptoms frequently appearing before cardiac symptoms. The vessels involved in erection are narrower than the coronary arteries, so vascular problems can show up there first. That is a reason not to quietly wait it out: a persistent change in erection quality is worth a conversation with a doctor or urologist even if sex is not your main concern.

What the scale is actually for

The Erection Hardness Score will not tell you whether you are normal — it was never built to answer that, and the honest answer to “how hard should an erection be” is that firmness varies widely within one man, let alone between men. What it does is turn a vague, anxious impression into a number you can compare with last month’s. That is a small thing. It is also most of what a self-assessment can legitimately offer, and considerably more than guessing.

Questions

What is the Erection Hardness Score (EHS)?

The Erection Hardness Score is a four-point scale used in sexual medicine to rate erection firmness. Grade 1 means the penis is larger but not hard. Grade 2 means hard but not hard enough for penetration. Grade 3 means hard enough for penetration but not completely rigid. Grade 4 means completely hard and fully rigid. It was validated as a research measure by Mulhall and colleagues in 2007.

How hard should an erection be?

There is no single correct answer, because erection firmness varies within the same man from day to day. The scale was built to track change, not to define a normal value, so a single grade 3 evening after a short night or a few drinks says almost nothing on its own.

Does not getting morning wood mean something is wrong?

Not on its own. Sleep-lab research going back decades has found that healthy men have several erections per night, tied to REM sleep, but whether you notice one on waking depends on which sleep stage you woke up in. A single morning without one means very little. A change that holds for several weeks or months is worth mentioning to a doctor.

Is the Erection Hardness Score accurate if I score myself?

It is a self-report scale by design, so it is only as accurate as you are honest. The single score is rough. Its value comes from repetition: scoring yourself the same way for two or three months turns a vague impression into a series you can actually read, which is something no single measurement can do.

Sources

Mulhall et al. 2007, Journal of Sexual Medicine — Validation of the Erection Hardness Score
Feldman et al. 1994, Journal of Urology — Massachusetts Male Aging Study
Leproult & Van Cauter 2011, JAMA — Effect of sleep restriction in young men
Dorey et al. 2004, British Journal of General Practice — Randomised controlled trial of pelvic floor muscle exercises
Gandaglia et al. 2014, European Urology — Systematic review of erectile dysfunction and cardiovascular disease
Veale et al. 2015, BJU International

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