Straw Size Guide: Which Straw Fits Your Cup
By Klean Kanteen | Bottles, Cups, Mugs, Tumblers, Food | Published: 2026-10-18
Category: How-to Guides
Learn how to choose the right straw diameter and length for your Klean Kanteen tumbler or cup. Our guide covers compatibility, cleaning, and real-world use.
Quick answer
Match the straw diameter to your lid's drinking slot and choose a length that reaches the bottom of your cup without sticking out too far. For most Klean Kanteen tumblers and cups, an 8mm diameter straw works best.
Why straw diameter matters
A straw that's too thin may not stay in place or deliver enough flow for thick drinks like smoothies. One that's too thick can be uncomfortable or fail to fit through standard lid slots. Klean Kanteen's stainless steel straws use an 8mm diameter, which balances sipping ease with lid compatibility for their Tumblers and Steel Cups.
Length: getting the right reach
A straw that's too short won't reach the bottom of a tall tumbler, leaving you unable to finish your drink. One that's too long can be unstable or poke out awkwardly. Measure from the lid's drinking hole to the bottom of the cup, then add about 1–2 inches for comfort. Klean Kanteen straws come in lengths designed to fit their most popular cup sizes.
Cleaning and care considerations
Reusable straws need regular cleaning to prevent residue buildup. Stainless steel straws are dishwasher-safe, but the silicone flex tip should be removed and cleaned separately. A straw brush helps reach the interior. The removable tip also makes it easy to replace if worn.
How to choose the right straw for your cup
- Check your lid's drinking slot: Measure the width of the slot on your tumbler or cup lid. Klean Kanteen's 8mm straws fit most of their lids, but if you have a narrow slot, a smaller diameter may be needed. A straw that doesn't fit the slot can't be used—always measure first.
- Measure the cup height: Place a ruler inside your cup from the bottom to the rim. Subtract about 1–2 inches to account for the lid and drinking comfort. Compare this to the straw length listed for the product. A straw that's too short won't reach the bottom; one too long may tip over.
- Consider what you'll drink: For smoothies, thick juices, or iced coffee, a standard 8mm diameter provides good flow. For water or thin beverages, the same diameter works fine—there's no need for a narrower straw. Thicker drinks need a wider diameter, but 8mm handles most daily drinks well.
- Decide on quantity: If you have one cup and drink mostly at home, a single straw or two-pack is enough. For families or multiple cups, a six-pack saves money and ensures you always have a clean straw ready. Buying a pack reduces the chance of losing your only reusable straw.
- Check the material and tip: Klean Kanteen straws are stainless steel with a removable silicone flex tip. The tip protects your teeth and prevents the straw from scratching your cup. Make sure the tip is food-grade and BPA-free. A removable tip makes cleaning easier and extends the straw's life.
Product facts
- Steel Straw - 8mm: The Steel Straw (8mm) is made from 18/8 stainless steel with a removable silicone flex tip. The 8mm diameter fits most standard tumbler lids, and the silicone tip prevents clinking against teeth while keeping the straw cool to the touch.
Steel Straw - 8mm - Straw 2-Pack - Black - SALE: The Straw 2-Pack (Black) includes two reusable straws with a silicone flex tip. A two-pack gives you a backup for home or one straw for the office and one for on-the-go, reducing the chance of being caught without a reusable option.
Straw 2-Pack - Black - SALE - Straw 6-Pack: The Straw 6-Pack is made from certified 90% post-consumer recycled stainless steel. If you have multiple cups or share drinks with family, the six-pack ensures everyone has a straw without buying single-use plastic.
