The Ninja Blender Duo with Auto-iQ is a full-size blender with a versatile performance. It comes with three differently-sized personal jars in addition to its 72-ounce main jar. You can use it to make fantastic smoothies, incredible almond butter, and snow-like crushed ice. Its Auto-iQ feature allows it to detect what size of jar you're using, which changes what presets you can select. It's amazingly easy to clean either by hand or in your dishwasher, but unfortunately, it can't hot blend.
The Ninja BL642 is good for multi-purpose use. It has a great build quality and a very versatile performance. You can use it to make fantastic almond butter, incredible smoothies, and snow-like crushed ice. The large-capacity main jar and three personal jars are all very easy to clean. However, you can't use it to blend hot ingredients.
The Ninja BL642 is amazing for smoothies and protein shakes. Using the 32-ounce jar, it easily processes leafy greens like kale and produces an outstanding smoothie. It can also make snow-like crushed ice, which is nice if you like to add it to your smoothies. However, if you use the main jar to make smoothies, the result is just okay.
The Ninja BL642 is incredible for crushing ice. It has a great, sturdy build quality, and you can use the main jar to make snow-like crushed ice.
The Ninja BL642 can't hot blend and isn't suitable for making soups.
The Ninja BL642 is fantastic for professional use. While it's entirely made of plastic, it has a great, sturdy build quality and its main jar has a large, 72-ounce capacity. You can use it to make smooth, spreadable almond butter, snow-like crushed ice, and incredible smoothies. It's really easy to clean, either by hand or in your dishwasher.
The Ninja Blender Duo with Auto-iQ BL642 is a bulky full-size blender. It's best stored on your kitchen counter or in a large cupboard, and you can also remove the main jar for easier storage.
The Ninja BL642 has an impressive build quality. While the motor base and transmission are made completely of plastic, they don't feel flimsy. It's easy to dock and undock jars from the base, and there are bright blue LED lights to indicate what presets are available for the jar you're using. The blender won't run unless it detects that a jar is properly docked. The jars are made of good-quality plastic, but unfortunately, the suction cups under the motor base don't seem to grip onto surfaces very well. The mirrored accents on the front of the blender are prone to fingertip smudges as well.
The Ninja BL642 comes with a large, 72-ounce capacity main jar, although it has a maximum fill line for liquids at 64 ounces. The jar is top-rack dishwasher-safe.
The Ninja BL642 comes with three differently-sized additional jars: 32 ounces, 24 ounces, and 18 ounces. Their maximum liquid capacities are 30 ounces, 22 ounces, and 16 ounces, respectively. There are two separate lines on each jar that indicate the total capacity and the maximum liquid capacity. There are also measuring marks to help you add the right quantity of ingredients to your blends, but they don't go all the way up the sides of the jars. For example, the largest personal jar's total capacity is 32 ounces, but the measuring marks only go up to 28 ounces.
The Ninja BL642's main blade assembly is similar to that of other Ninja blenders, such as the Ninja Mega Kitchen System BL770. It's shaped like a column with six sharp blades that spiral around it. There's also a second blade assembly for the personal jars. Both are top-rack dishwasher-safe.
The Ninja BL642's lid is made of plastic and has to be properly aligned to clip into place. There's a small window-like spout that can be used for pouring, but it's not a two-part lid and isn't intended for adding ingredients while blending.
The power cord should be long enough to reach an outlet near your counter. There's a place to wrap the cord on the back of the blender for easier storage.
The Ninja BL642 comes with several preset speeds and modes. At maximum speed, it's quieter than the Ninja Mega Kitchen System BL770.
The Ninja BL642 is fantastic for making almond butter. It has no issue processing the nuts if you start with 'Pulse' mode to crush them, then run the blender on low speed for roughly two minutes. When the mixture starts to develop a good consistency, blend on high for a few more minutes to finish the process. The result is very smooth, spreadable almond butter.
The Ninja BL642 makes an incredible smoothie in its 32-ounce jar. After running the 'Ultra-Blend' preset twice, the result is a uniform, cold, silky smoothie with no bits of kale leftover.
This blender also makes a great smoothie in its 18-ounce jar, although it has a somewhat worse, thicker texture than the smoothie made in the 32-ounce jar. We haven't tested the 24-ounce jar, but expect it to perform similarly to the 32-ounce jar. Unfortunately though, if you use the main jar, the result is just okay. After running the 'Frozen Drinks Smoothies' preset, the smoothie was cold but very thick with noticeable bits of kale leftover.
The Ninja BL642 is fantastic for crushing ice. It makes truly snow-like crushed ice very quickly.
This blender has several preset modes and speeds. There are buttons for low, medium, and high speed, as well as one for pulse mode. The 'Auto-iQ' feature allows it to automatically detect what size jar you're using, which changes what preset modes are selectable. The 'Puree' preset is available with any jar, but the length of the blend changes depending on whether you're using the main jar or one of the personal ones. There are four different presets in all:
This blender is amazingly easy to clean. It's easy to rinse clean if you've been working with liquidy ingredients, and a quick blend with soap and warm water takes care of most stickier messes. The blade assembly is removable, which makes it easier and safer to clean out sticky food like almond butter, although you may need to occasionally use a brush to clean stubborn residue from the bottom of the jar. You should take care when cleaning the main jar by hand, though, as it has sharp edges around the rim where the lid fits into place. Luckily the main jar is also top-rack dishwasher-safe, along with all the lids, blade assemblies, and personal jars.
This blender has an 'Auto-iQ' feature that allows it to detect what size of jar you're using, which affects what presets you can select and the length of some presets. However, it doesn't have many other extra features, and you can't use it to blend hot ingredients.
There are a few variants of the Ninja Blender Duo with Auto-iQ available. We tested the BL642 model, and you can see its label here. Depending on the model number, this blender can come with several differently-sized personal jars. As we tested the model that comes with all three differently-sized personal jars, we expect our results to be valid for the other models as well. However, depending on which one you have, some of our tests may have been performed using a jar that isn't included with your blender.
|640||Two personal jars (2x 24 oz)|
|641||Two personal jars (32oz and 24oz)|
|642, 642W, 642W1||Three personal jars (32oz, 24oz, 18oz)|
|642Z||Three personal jars (32oz and 2x 24oz)|
If your model isn't listed here or you come across another variant, please let us know in the discussions so we can update our review.
The Ninja Blender Duo with Auto-iQ BL642 has a similar look and design as other full-size Ninja blenders, such as the Ninja Professional Plus Kitchen System with Auto-iQ and the Ninja Professional Plus Blender with Auto-iQ. It performs better for most uses than those blenders, though, and is particularly well-suited for making single-serves because of its three differently-sized personal jars. Using the 32-ounce jar, it makes a better smoothie than most blenders that we've tested. If you want to see more options, check out our lists of the best blenders for smoothies, the best blenders for crushing ice, and the best blenders for frozen drinks.
The Ninja Blender Duo with Auto-iQ BL642 is better for most uses than the Ninja Professional Plus Kitchen System with Auto-iQ. The Duo makes much better smoothies and produces smoother, more spreadable almond butter. It also comes with three personal jars, while the Professional Plus Kitchen System comes with two. However, the Kitchen System also includes a food processing attachment, although we don't currently test it.
The Vitamix Explorian E310 and the Ninja Blender Duo with Auto-iQ BL642 perform similarly for many purposes, and which you may prefer depends on your needs. Both models produce fantastic smoothies and incredible almond butter, but the Duo makes crushed ice with a better texture. It's also better suited for making single-serves because it comes with three personal jars in addition to the main jar. On the other hand, while the Vitamix doesn't have any additional jars, it's quieter and has a much better build quality. It can also hot blend, unlike the Ninja.
The Ninja Blender Duo with Auto-iQ BL642 is a better blender than the Ninja Professional Plus Blender with Auto-iQ. They have a similar appearance, but the Duo makes significantly better smoothies and almond butter. It also comes with three personal jars in addition to its main jar. On the other hand, the Professional Plus Blender is easier to clean.
The Ninja Blender Duo with Auto-iQ BL642 is a better blender than the Blendtec Designer 725. The Ninja makes significantly better smoothies, much better almond butter, and comes with more additional jars. On the other hand, the Blendtec has a much better build quality. Also, while neither can blend hot ingredients, the Blendtec has a Hot Soup preset meant to warm up cold ingredients.