Madi Koetting/Taste of Home (Madi Koetting/Taste of Home)What’s one thing 40+ ounce water bottles, like Yeti or Hydro Flask, and coffee mugs all have in common? They don’t fit in most car cup holders, resulting in rattling bottles on the car floor or spilled coffee. Fed up with not having a spot to fit my large-capacity water bottles and cute travel mugs, I came across the answer: A car cup holder expander. Spoiler: Road trips are so. much. better. thanks to this genius find.What Is a Car Cup Holder Expander?Well, it’s exactly what it sounds like. A car cup holder expander makes room for large water bottles and coffee tumblers that don’t fit in regular car cup holders. Boasting an adjustable base that expands to fit cup holders between 2.6 and 3.8 inches, it offers just the right amount of room to fit every type of bottle or mug. Simply twist the cup holder extender until it’s secure and you’ve got the perfect spot for coffee mugs and lofty water bottles. Reviewers also note it works in golf cart cup holders, riding mowers and tractors, too.Before testing this product, I used to hold my Hydro Flask or travel mug in my hands while riding in the passenger seat. Or worse, I would throw my larger-than-life water bottle on the passenger seat while driving. Now, that problem is a thing of the past with this road trip game-changer.AdvertisementAdvertisementPro tip: If your car’s cup holders are more than 2.75 inches deep, the brand recommends the long base version. VIA MERCHANT Swigzy Car Cup Holder Expander $26.99 at Amazon$26.99 at EtsyHow to Use a Car Cup Holder ExpanderReady for the easiest setup ever? The car cup holder expander arrives in three pieces that easily fit together. Simply attach the adjustable base to the cup holder with the included screw. Then pop in the circular padding into the cup holder and it’s ready to work its magic.The twistable base adjusts to your car cup holder’s size in no time. Just pop it in and twist it until it’s snug and secure. As simple as it sounds, the car cup holder extender never fails to impress me. I especially love the silicone tabs around the holder’s edges to keep bottles from rattling around. And the side slot, which is ideal for cups with handles, is a total plus if you prefer taking your favorite coffee mug to the office and can’t go anywhere without your Stanley tumbler.The Best Amazon User ReviewsWhen an Amazon product has more than 10,000 ratings with an average of 4.6 stars, it’s usually a keeper—as is the case with this problem-solving car cup holder expander. Here’s what other reviews love about the car cup holder expander:AdvertisementAdvertisementVerified Amazon reviewer J. Patton says, “I bought my first Swigzy August 2025. It’s sturdy and still in perfect condition, so I’m back eight months later for a second one for me, plus another for gifting. Two fit perfectly in my front seat cupholders (2021 Toyota Highlander Hybrid), can hold 2 40-oz water bottles. They’re super simple to assemble, and tall enough that large drinks won’t tip. I also like supporting small businesses when possible!Another verified reviewer, Matthew N., says this of his Swigzy, “Worth every penny. Very well made product. I love how I can now have larger water containers in my Crosstrek cupholder. It has genius design that kind of screws into cupholder so it doesn’t move around. It also makes the water bottle sit up higher which I like. One of my best Amazon purchases.”Scroll through the Amazon reviews, and you’ll see that car owners of various makes and models are happy with their Swigzy purchases. But it’s not just for cars! Verified reviewer Texas Gator Bait raves about its usefulness on riding lawn equipment: “I purchased the Swigzy Car Cup Holder Expander Adapter to use on my zero-turn mower and my John Deere tractor, and it works great. The expanding base fits securely in the factory cup holders and stays firmly in place, even with vibration and rough terrain. It easily holds larger insulated bottles and tumblers that would not normally fit. The build quality feels durable and well made. Very practical accessory and definitely worth the purchase.”Where to Buy VIA MERCHANT Swigzy Car Cup Holder Expander $26.99 at AmazonAdvertisementAdvertisement$26.99 at EtsyWith road trip season in full swing, there’s no better time to snag this car cup holder, which it goes for $27 on Amazon and Etsy. Trust me, I’m relieved to have this genius product every time I hop in the car with my awkwardly-shaped travel coffee mug or Hydro Flask water bottle!FAQWhat is a cup expander?A car cup holder expander provides more room for large water bottles or travel mugs that won’t fit in standard car cup holders. Most available models are made of plastic and rubber so that they are durable and will stay put during use.Does a 24 oz Hydro Flask fit in a car cup holder?Yes, a 24-ounce Hydro Flask should fit in a standard car cup holder.What size mason jar fits in a cup holder?Any 24-ounce mason jar should fit in a car’s cup holder, but anything larger may need a car cup holder expander.Does a Yeti 26 oz fit in a car cup holder?No, a 26-ounce Yeti Rambler water bottle does not fit in standard car cup holders and may need an expander to fit. But, some storage compartments in car doors may accommodate a bottle of this size.Why You Should Trust UsMadi Koetting is a pioneer of Taste of Home‘s social media and editorial team with hands-on experience testing and reviewing top products for brands including Reader’s Digest, The Everygirl, Stylecaster, Family Handyman and more. During her time with these publications, she has reviewed thousands of products in the lifestyle sphere. Given her extensive experience, she is an excellent candidate to review the Swigzy car cup holder expander.AdvertisementAdvertisementAlexandra Mantella, Content Updates Editor at Taste of Home, updated and contributed research to this piece. She has over five years of experience in product testing, research and commerce writing. Previously, she served as a commerce content update editor at Bob Vila.