Dildo size guide: what size dildo should you get?
Bigger isn’t always better. Here’s how dildo sizes compare to the real thing, and how to pick the one you’ll actually enjoy.
Dildo listings throw a lot of numbers at you, and the “7.5 inch” on the box rarely tells you how big it feels. The two numbers that matter are insertable length and width, and the easiest way to judge them is to compare them with an average penis.
How big is the average penis?
The best-known study, a 2015 review in BJU International that pooled measurements taken by health professionals, put the average erect penis at 13.1 cm (5.2 in) long with a girth of 11.7 cm (4.6 in) around. A larger 2023 meta-analysis of 55,761 men found an average erect length of 13.9 cm (5.5 in). So most real cocks are about 5 to 5.5 inches long and about 1.5 inches (3.7 cm) wide.
That’s worth knowing, because a “7 or 8 inch” dildo is already bigger than average, and an 8-inch dildo with a 2-inch width is a big step up from most partners.
How to read a dildo’s size
- Insertable length: how much can actually go in. It’s shorter than the total length once you take off the balls and base, often by 1 to 2 inches.
- Width (diameter): how wide it is across. This matters more than length for comfort, especially for anal.
- Girth (circumference): the distance around. Divide by 3.14 to get the width.
- Firmness: dual-density silicone has a soft outside and a firm core, so it feels more forgiving than its size suggests.
| Level | Width | Insertable length | Good for |
|---|---|---|---|
| Beginner | 2.5–3.2 cm (1–1.25 in) | 10–13 cm (4–5 in) | Your first toy, especially for anal |
| Average, real feel | 3.5–4 cm (1.4–1.6 in) | 13–16 cm (5–6.3 in) | Feels like a typical partner |
| Bigger | 4–5 cm (1.6–2 in) | 16–20 cm (6.3–8 in) | When average feels easy |
| Size queen | 5 cm+ (2 in+) | 20 cm+ (8 in+) | Experienced bottoms who train up to it |
Which size should you get?
- New to anal: start at the beginner width, or with a plug training kit, and size up slowly.
- Want it to feel like the real thing: pick an average width with a realistic shape, head and balls.
- Already comfortable: go up one step in width, not two. Width is what you’ll notice.
- Riding hands-free: choose a suction cup base, and remember the base adds height but not insertable length.
Sizing up safely
- Use plenty of water-based lube, and more than you think.
- Warm up with fingers or a smaller toy first.
- Go slowly, breathe out as you push, and stop if it hurts: pain is a signal, not a challenge.
- Only use toys with a flared base or suction cup for anal, so nothing can slip inside.
Tip: New to toys? Start with butt plugs for beginners and the lube guide, then come back for your first dildo.
Sources
Dildos
Good questions
What is the average dildo size?
Most realistic dildos sold are 7 to 8 inches long overall, which is bigger than the average erect penis of about 5.2 to 5.5 inches.
What size dildo should a beginner get?
Something about 1 to 1.25 inches wide with 4 to 5 inches insertable, or a plug training kit.
Does width or length matter more?
Width. It decides how full and how comfortable a toy feels, especially for anal.
How do I convert girth to width?
Divide the girth (circumference) by 3.14. A 4.6-inch girth is about 1.5 inches wide.
Is a 7.5 inch dildo big?
It’s bigger than average, but after the balls and base, the insertable length is usually closer to 6 inches.