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Guide to Sex Toy Measurement
Education hubNo pressureNo wrong size
Education hub · Measurement
A guide, not a sales page
Understanding size, without the guesswork.
A photograph gives you no reliable sense of scale. Something that looks manageable on a screen can feel very different in practice, and the reverse is just as true.
The six measurements → Or put a number in context →
Unsure about a specific product? Ask us and we will check it for you.
Why it matters
Toys come in a far wider range than bodies naturally encounter.
Knowing the numbers before you buy tells you whether something is a comfortable starting point, an interesting challenge, or something to work toward over months.
Size also affects things people forget to think about: how portable it is, how easy it is to store discreetly, and how it actually feels in use rather than how impressive it looks in a listing.
Always check the stated measurements on the product page. This guide turns those numbers into something you can picture.
The terms
Six measurements, defined.
Two of them are the ones that actually matter, and they are the two most often left off a listing.
LengthOverall length, top to bottom, including any base or handle. Useful for storage, less useful for anything else.
WidthThe longest distance from one side through the centre to the other. On a round piece this is the diameter. On an asymmetrical one it is the maximum width.
HeightFor pieces with a base, the vertical measurement. Where height is listed, length means the longest horizontal measurement and width the shorter one.
Insertable lengthOne of the two that matter. The maximum length that can enter the body. On a stroker, the depth of the internal canal.
Insertable widthThe other one that matters. The maximum width that can enter the body, or the internal width on a stroker. This is what you feel.
GirthThe distance around the widest insertable part. Often missing from listings, and easy to work out yourself.
If girth is missing
Work it out in one step.
Many listings give width but not girth. They are the same measurement expressed differently.
Girth = width × 3.14
A piece 1.5 inches (3.8 cm) wide has a girth of about 4.7 inches (12 cm).
Longer pieces do tend to be wider, but not always. Long and slim exists, and so does short and thick. If you only look at one number, make it insertable width, because girth follows from it and it is what determines comfort.
Putting a number in context
Compare it to something you can picture.
Numbers on a screen mean very little. These do not.
ReferenceSomething you already have a sense of
Length
Average flaccid penisVeale et al., 2015
3.6 in · 9.2 cm
Average erect penisVeale et al., 2015
5.2 in · 13.1 cm
A soft drink can375 ml
5.0 in · 12.7 cm
A commonly chosen dildoTypical mid range size
7.0 in · 17.8 cm
A large dildoNearly three cans stacked
14 in · 35.6 cm
Penis figures are from Veale et al., BJU International, 2015, a systematic review of over fifteen thousand men and the largest available. Averages are context, not a target. Nothing on this page is prescriptive.
If you are starting out
Smaller and more flexible is the supportive choice.
You can always go larger once you know what feels good. Going the other way is a wasted purchase and often a bad experience.
Beginner friendly sizing
- Insertable length: 7 inches or 17.8 cm and under.
- Insertable width: 1.2 inches or 3 cm and under.
- Girth: 3.8 inches or 9.6 cm and under, which follows from the width above.
- Flexibility: a softer silicone with some give feels considerably smaller than a firm one at the same measurement, because it moves with you.
Softer silicone only. Anything sold as realistic feel is usually TPE or TPR, which is porous and cannot be sanitised. Our standard excludes it.
Common questions
Answered plainly.
Which measurement should I actually look at?
Insertable width, first and always. Girth follows from it, and it is what determines comfort. Insertable length matters second. Overall length tells you about storage rather than experience.
Is bigger better?
No. Going too large is by far the more common regret in this category, and it is the reason a great many pieces end up unused in a drawer. There is no correct size, only the one that suits your body and your experience so far.
Does firmness change how big it feels?
Considerably. A softer silicone with give feels smaller than a firm one at identical measurements, and glass or steel feel larger again because they have no give at all. Two pieces with the same numbers can be completely different experiences.
What if the product I received does not match the listing?
Tell us. We publish the measurements we are given and we would rather correct them than defend them. Email us and we will check the piece and update the listing.
How do I measure something I already own?
A soft tape measure around the widest insertable part gives you girth directly. If you only have a ruler, measure the width across the widest point and multiply by 3.14.
Can you check a specific product for me?
Yes. Email hello@schoolofsexualwellness.com with the product name and we will measure it and tell you. There is no wrong question.
This page is education rather than medical advice. Products are for personal wellness and pleasure, are not medical devices, and are not intended to diagnose, treat, cure or prevent any condition.
Start where you are comfortable
There is no correct size.
Only the one that suits your body and where you are today. Smaller and more flexible is always a reasonable place to begin.
Shop the range → Or ask us to check a size →
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