Dildo Size Guide - How to Get the Right Length and Width: A Visual Guide
Dildos come in every size from the petite beginner probe to the 12-inch powerhouses. Picking one that fits your body and your pleasure style can feel overwhelming, but don’t worry. Betty’s got you covered.
When it comes to size, four key measurements matter:
1. Length
2. Insertable Length
3. Width
4. Girth
These are 4 distinct measurements. Usually, the general rule of thumb is, the longer the dildo, the greater the width (and girth), but that's not always the case. You can have short, thick dildos, and very long skinny dildos.
1. DILDO LENGTH
When a manufacturer lists a dildo’s length, they’re talking about the total measurement from tip to base, everything included. That means if your dildo has balls, a flared base, or a suction cup, those features count toward the total length.
It’s important to know that not all of that length is usable, which brings us to…
2. INSERTABLE LENGTH
Insertable length tells you how much of the dildo can actually go inside your body. Since external features like balls or suction cups take up space, the insertable length is usually shorter than the total length.
For example, an 8-inch dildo with balls might only have 5 or 6 inches of insertable length.
Think of it like this:
Insertable Length = Total Length – Base/Attachments
If you’re using your dildo with a harness, a model without balls often provides more insertable length and better control. But if realism is your thing, go for the version with balls, it offers that lifelike look and feel.
3. DILDO WIDTH
Width (sometimes called diameter) is the measurement straight across the widest part of the dildo. This number gives you a sense of how full the toy will feel.
For reference, the average penis is about 1.5 inches wide, while a soda can is around 2.6 inches wide. So, if you’re browsing and notice a dildo approaching soda-can territory, be sure that’s the experience you want. It’ll be a stretch, literally.
4. DILDO GIRTH
Girth refers to the circumference or the distance around the dildo. It’s directly related to width: the wider the dildo, the larger the girth.
If you prefer visualizing, width is often easier to picture. But if you see a dildo listed as having a 6.5-inch girth, that translates to roughly a 2-inch width. (Yes, this is where your middle-school geometry finally pays off.)
How to Pick the Best Dildo for You
If you’re new to penetration or toys in general, start small — something close to average penis size (around 6 inches long and 1.5 inches wide). Once you know what feels good, you can explore bigger sizes, different shapes, or textured designs.
Ready to shop?
Want to dive deeper? Check out our Complete Guide to Dildo Materials for help choosing between silicone, glass, and more.
About the Author: Carolyn Eagle, the Pleasure Librarian, is the founder of Betty’s Toy Box and a certified sex educator who writes about pleasure, confidence, and sexual wellness with humor, honesty, and zero shame.