Dildo sizes explained: which length and girth to choose

For a first dildo, choose about 15 to 19 cm in total length with a diameter of 3 to 4.5 cm; that suits almost everyone and leaves room to grow. Girth decides comfort far more than length, so when you want more, go up in diameter by about half a centimetre at a time. XL and XXL dildos, from 26 cm long or over 5.5 cm across, are for people who already know their size.

Below is a size table with real measurements from our dildos, followed by insertable length, girth, measuring, suction cups, harnesses and materials.

Dildo sizes at a glance

Manufacturers use these labels loosely: the Lovetoy XXL 10.5 inch measures 27 by 6.5 cm, which is our XL row. Read the centimetres, not the name.

Total length versus insertable length

The length in a product title is usually the total length, from the tip to the bottom of the base. The suction cup, the flared base and, on realistic models, the testicles never go in. The insertable length is what counts.

The Legend Tigrax is 17.5 cm in total but 12.5 cm insertable. The XISE Armand L is a 26 cm dildo with 18 cm insertable, while the Master Series ribbed dildo has no testicles and gives you 17.2 of its 18.5 cm.

Girth: diameter and circumference

Girth is how thick a dildo is, given as a diameter (the width across) or a circumference (the distance around). Multiply the diameter by 3.14 to convert: 4 cm across is about 12.5 cm around, 5 cm about 15.7 cm and 7 cm about 22 cm. A small step in diameter is a big step in feeling, because the stretch grows all the way around.

How to measure

Take a toy you already enjoy. Measure the insertable part from the tip to where the base or testicles start, and the widest point with a ruler across it, or wrap a strip of paper around it for the circumference. Then change one thing at a time: a bit longer or a bit thicker, not both. No toy yet? Start in the small or medium row.

The best dildos by size

• Best small dildo: Fun Factory Limba Flex S. About 12 by 3 cm in silicone, with a bendable core that holds the angle you set.
• Best slim first dildo: Chisa Raw Recruit M. 15 by 3 cm in silicone, gently curved, with a flat base that fits a harness.
• Best compact realistic dildo: Legend Tigrax. Liquid silicone, 4.3 cm across and heavy for its size, so it stays put.
• Best medium all-rounder: SilexD Model 2, 7.5 inch. 19 by 4.6 cm in dual density platinum silicone, suction cup and harness compatible.
• Best for length without girth: SilexD Angel 8 inch. 15 cm insertable at just under 4 cm across.
• Best textured medium dildo: Master Series ribbed dildo. Ribbed along the whole shaft, 4.6 cm at the widest.
• Best large step up: SilexD Model 1, 9 inch. 17 cm insertable at 5 cm across, soft silicone over a firm core.
• Best 26 cm dildo: Baile Sliding Skin 26 cm. 19 cm insertable, 5.5 cm across, with an outer skin that slides over the core.
• Best thick dual density XL: XISE Armand L. 5.2 cm across, with a firm core under a softer layer.
• Best first XL in silicone: Lovetoy XXL 10.5 inch. 27 by 6.5 cm in dual layer platinum silicone, harness compatible.
• Best for girth over length: Lovetoy King Size Nature. Only 24.5 cm long but 7.7 cm across.
• Best XXL for experienced players: SilexD 15 inch. 38 by 7 cm with an extra strong suction cup.
• Best bendable monster dildo: Lovetoy XXL 16 inch. About 40 cm long with a metal frame inside that holds any position.

Dildos compared

Figures are the manufacturers' own; where a value is not stated, check the product page.

XL and XXL dildos

An XXL dildo is mostly a girth toy. Even with the 38 cm SilexD, most people use about a third of the length; the rest is for grip and the view. A monster dildo is also heavy, so a strong suction cup or a firm hand on the base matters. Prefer a wild shape? See fantasy and novelty dildos.

Suction cups and harness fit

A suction cup needs a smooth, non-porous surface such as tile or glass, and both should be clean and dry. Press it down firmly and test it before you put weight on it; heavy dildos hold best on a wall or floor tile.

For a strap-on, the base must be flat or flared and wider than the shaft, so it sits in the harness ring without slipping through. Several SilexD, Lovetoy and Master Series models are harness compatible. Compare the base with your ring and see our strap-on dildos and strap-ons and pegging sections.

Materials: silicone, dual density and the rest

Silicone is non-porous, odourless and lasts for years; most platinum silicone dildos can be boiled.

Dual density means a firm core under a softer outer layer, so the dildo keeps its shape while the surface gives like skin, which makes larger sizes easier to take. Our guide to liquid silicone and dual density dildos explains more.

PVC, TPE and sliding skin are softer and cheaper but porous: keep them as a personal toy or use a condom, and store them apart from silicone. Many realistic dildos and suction cup dildos use these materials.

Going up a size safely

• Warm up with fingers or a smaller toy, and be properly aroused first.
• Use plenty of lube and add more as you go.
• Go slowly, breathe out as you push and let the body relax instead of forcing it.
• Increase diameter in small steps and stay at each size for a few sessions.
• Stop at sharp pain, numbness or bleeding.
• For anal play, only use a flared base and read anal play for beginners first.

Still choosing your first one? Our guide to choosing a dildo covers shapes and uses.

Lube and cleaning

Use a water-based lubricant with silicone, PVC and TPE; silicone lube can damage silicone toys. For anal play, a thicker anal lube lasts longer. Wash before and after use with warm water and mild soap or a toy cleaner, dry completely and store each toy separately, out of the sun.

Frequently asked questions