Earn up to 10% back on every purchase with SMOKEA® Rewards - it's free to join!

Bong Downstem Sizes: How to Measure Your Pipe

RSS
 A clear glass bong with a downstem beside a pool.

Downstems are an essential bong accessory. They're the straight tube that reaches down into the belly of your water pipe and gives you that all-important airflow to filter and cool your smoke. Almost every water pipe comes with a removable downstem. Unfortunately, they can also break, even if it's not a glass downstem. No need to fear! If you've got a new bong or a recently broken older one, here's our step-by-step guide for how to measure a replacement downstem to get the perfect new bong bowl piece for a smoother hit.

Step 1: Gather Your Supplies

This step is easy — you don't need many supplies. The most important piece to have is, obviously, your bong.

Next, grab a ruler or measuring tape. If you don't have either of those, get a pencil and a penny. (Try your couch cushions for these.) Bong downstem sizes are fairly straightforward: the most common are 10mm, 14mm, and 18mm. Your pencil and coin are key parts of how to measure a downstem.

Step 2: Check Your Joint

Two pennies sitting on top of each other.

A penny is almost exactly 19mm in diameter. You're going to use your coin to figure out your joint size.

Start with the female ground joint of your bong. If you can barely get a side of the penny into the joint, it's 10mm (or if you can't slide a pencil into it). If the penny fits in about ¼ of the way, it's a 14mm joint. If it fits about halfway, it's an 18mm joint.

Need to measure a bong downstem's size for a male joint? Similar sizing applies. If your joint covers a small fraction of the penny, it's 10mm. If it covers about ¾ of the penny, it's 14mm. If it covers almost all of the penny, it's 18mm.


Step 3: Find the Length of Your Bong Downstem

Learning how to measure a downstem includes the length. This is where your pencil comes in.

Insert the pencil into the female ground joint of your bong so the tip hovers about ½” above the bottom. Ideally, it would hit the water should the pipe be full. Make a mark on the side of the pencil where it exits the joint.

Now, to measure your bong's downstem size, measure from the tip of the pencil to that mark. Keep in mind that downstem measurements typically don't include the length of the glass ground joint. These joints are usually one inch long, so you'll want to subtract that from the measurement you took from your pencil to get the perfect length.

Don't have a ruler? Remember that pennies are 19mm wide. Count how many pennies fit from the tip of the pencil to your mark and multiply by 19 to get an approximate measurement (remember to subtract 1 inch or 25 mm).

If you have a 10mm joint and can't fit a pencil inside, other options include the ink reservoir of a pen, or you can maybe tape some toothpicks together in a pinch.

That's it, now you know how to measure a downstem!

Choose Your New Downstem from SMOKEA®

Now that you've found your perfect bong downstem size, find your new favorite piece from SMOKEA® and enhance your smoking experience! We have a wide variety of materials so you can find the right downstem for your bong.. Join our Rewards Program to save big and shop now!

Previous Post Next Post

  • SMOKEA Blog
 
  • Product Reviews
  • Site Reviews
10/10/2025
Anonymous
United States
All of the big high thca carts are as good as glo, iykyk, and this is spot on with the terps and pinch. Better than almost all ofbthe dispensary carts I’ve bought. Worth every penny
Big High 1g THCA Vape Cartridge - Gorilla Glue
10/09/2025
Tanner
United States
My tolerance is not very high so I would only took half of one. But man these really hit after a long day. Taste is pretty good too
TRĒ House Delta 8 High Potency Gummies - Blue Raspberry
10/07/2025
Victor M.
United States
This vape is great ! It has a sweet pungent taste and hits pretty hard. Will definitely try more of this brand.
Torch 5g THCA Live Rosin Disposable Vape - Mango Meringue
10/07/2025
Victor M.
United States
I ordered one of these on 10/01/25 and received my order in less than a week. The effects of this vape are strong and very well worth it for the price. The flavor is great as well. With hints of fruits and sweet after taste. Will definitely be buying some more of this brand.
Dome Wrecker 5g Liquid Diamonds Blend Vape - Rainbow Runtz
10/07/2025
Anonymous
United States
Excellent, Definitely Dispensary Grade!! 👍👍
Modern Herb Co THCA Live Resin Uncut Cartridge - Golden Goat
10/06/2025
Robert S.
United States
Very easy transaction from start to finish great price for the product quick shipping would definitely recommend to family and friends
Headway 12" Lazy Boy Acrylic Bong
10/05/2025
Rob
United States
I found these is Florida, I put my in a water bottle and sip on it, I must be a light weight because if I drink a full one I’m done for. They tastes good and go down smooth and great feeling.
Delta Beverages Delta 9 Live Resin Cannabis Water - Blood Orange
10/05/2025
Rob
United States
Went on a side by side ride. Just chilling in the back seat. Drank one and started feeling awesome! The Su was going down I plan on buying more. I was thinking 10mg isn’t much. But it’s pretty gravy for me
Torch THC Seltzer - Mango Pineapple
10/05/2025
Rob
United States
Perfect for doing right before bed. And smells just like grape which is awesome. Throw it in one of those hidden vape batteries and just looks and smell like a vape from a smoke shop. Plus will help you sleep, if they weren’t sold out I would buy more.
TRĒ House 1g Live Resin HHC Cartridge - Grape Ape
10/03/2025
John G.
United States
Dependable trapdoor to my happy place at a painless fee.
TRĒ House Delta 9 Gummies - Blue Raspberry
10/03/2025
John G.
United States
Dependable trapdoor to my happy place at a painless fee.
TRĒ House Delta 9 Gummies - Blue Raspberry
10/03/2025
shawn b.
United States
the torch brand is pretty good. I bought 2 different torch tanks both were great me and dad enjoyed them very much. not to strong , but not to weak. just rite! Would buy this brand and product again. and im very picky!
Torch 1g THCA Live Resin Blend Cartridge - Moonwalk Haze
10/03/2025
Shawn N.
United States
Always good when I deal with smokea
SMOKEA 1 1/4 Premium Hemp Rolling Papers
10/02/2025
Veneranda D.
United States
I’m going to review the overall process of ordering from this site… Easy process to order, updates on delivery and quick! The product is great and exactly what we’ve been looking for. We had one a year ago that shattered on ceramic tiles. We were unable to find this in any stores we’ve visited. So...I’m going to review the overall process of ordering from this site… Easy process to order, updates on delivery and quick! The product is great and exactly what we’ve been looking for. We had one a year ago that shattered on ceramic tiles. We were unable to find this in any stores we’ve visited. So glad you guys had it!
Blazing Blue Glass Honeycomb Screen Chillum Pipe
10/02/2025
Anonymous
United States
Everything went smooth. Quality product!
GRAV Frit Spoon
10/01/2025
Thomas D.
United States
love at first sight
Human Grade 6" Hourglass Sidecar Bubbler
10/01/2025
Anonymous
United States
It's my favorite piece todate
Headway Big Boy 24"-72" (2ft - 6ft) Acrylic Bong
10/01/2025
Ezra M.
United States
Nice and short, easy to use.
SeshGear Shorty Color Beaker Bong
10/01/2025
Kristen F.
United States
It was exactly what I was looking for
SMOKEA Silicone Dab Straw
09/30/2025
Ashley R.
United States
Excellent pull, easy clean, great looks
Human Grade 10mm Horn Bowl
09/30/2025
Anonymous
United States
They burn very well. Seems to be made a very good quality. Good product
SMOKEA 1 1/4 Premium Hemp Rolling Papers
09/30/2025
Brian p.
United States
Great flavor and awesome uz
Torch High Potency THC Seltzer - Raspberry Lemonade
09/26/2025
ES
United States
Well I enjoyed this one , it was a great strain for me
Death Row Records 3.5g THCA Flower - Animal Cookies
09/26/2025
Kimberly J.
United States
It’s the perfect size tray and I love the magnetic lid!!
TRĒ House Small Metal Rolling Tray
09/25/2025
Bob Y.
United States
Tokes pretty smooth and it’s easy to clean. Great quality pipe
Big Pipe 3.5" MCH Microcooler Metal Pipe
09/25/2025
Diane L.
United States
Overall I'm happy with it! Just be careful 🧐 to not add too much water if you don't want bong water with your hit!
Headway 10" Straight Acrylic Bong
09/25/2025
Geo
United States
My favorite, exceptional taste and aroma with a very happy effect!
Lost Jane 1g Exotic THCA Flower - Pink Cherry Gelato
09/25/2025
Geo
United States
Very nice taste with a mild aroma with lots of laughter, really enjoyed myself!
Lost Jane 1g Exotic THCA Flower - Kiwi Kush Berry
09/25/2025
Geo
United States
Great taste and aroma with a nice peaceful easy feeling!
Lost Jane 1g Exotic THCA Flower - Turbo Lemon Cake
09/25/2025
Geo
United States
Works great!
SMOKEA Metallic Steamroller Pipe
REVIEWS