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. Its Auto-iQ feature allows it to detect what size of jar you're using, which changes what presets you can select. Like most full-size blenders from this brand, it can't hot blend and has a very sharp blade design that makes it tricky to clean by hand.
Our Verdict
The Ninja BL642 is okay for multi-purpose use. It's outstanding for crushing ice and easy to use to make smooth dips and spreads like nut butter. It comes with three personal jars that are well-suited for single-serves smoothies. However, it struggles to smoothly blend fibrous ingredients in its main jar, so big batches of smoothies or soup have a grainy texture. It can't hot blend, and it's hard to clean by hand.
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Personal jars make fantastic smoothies.
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Great build quality.
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Can't hot blend.
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Difficult to clean by hand.
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Not good for big batches of fibrous ingredients.
The Ninja BL642 is excellent for single-serve smoothies. It comes with three personal jars with to-go lids that you can use as travel cups after blending a smoothie. It makes a smooth blend with common smoothie ingredients like fruit and leafy greens, although some blenders do it faster. The jars and lids are also dishwasher-safe for easy clean-up.
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Personal jars make fantastic smoothies.
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Great build quality.
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Difficult to clean by hand.
It's good for multiple servings of smoothies. The main jar has a 72-ounce capacity, which is great if you're serving a crowd. However, in the main jar, it struggles to smoothly blend fibrous fruit and vegetables like leafy greens, even after several minutes of blending. It's fantastic for crushing ice, though, so if you want to make blended margaritas and other drinks with ice and liquid, that won't be as much of an issue.
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Makes snow-like crushed ice.
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Great build quality.
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Main jar has a large capacity.
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Difficult to clean by hand.
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Not good for big batches of fibrous ingredients.
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.
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Makes snow-like crushed ice.
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Great build quality.
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Difficult to clean by hand.
You can't use the Ninja BL642 to blend hot ingredients, so it's not ideal for making soup. The main jar has a big capacity that can fit a recipe in one batch. However, even if you use room temperature ingredients, it struggles to make a completely smooth puree with fibrous vegetables like broccoli in its main jar.
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Great build quality.
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Can't hot blend.
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Difficult to clean by hand.
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Not good for big batches of fibrous ingredients.
The Ninja BL642 is decent for professional use. It's well-built and fairly versatile since it's very well-suited for crushing ice and decently easy to use for nut butter. It smoothly blends small batches of fibrous fruits and vegetables in recipes like smoothies but doesn't perform as well with bigger batches. It can't hot blend and doesn't have a wide range of speed settings or a 2-part lid.
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Makes snow-like crushed ice.
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Great build quality.
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Main jar has a large capacity.
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Can't hot blend.
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Difficult to clean by hand.
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Not good for big batches of fibrous ingredients.
- Multi-Purpose
- Smoothies (Single Serving)
- Smoothies (Multiple Servings)
- Ice Crushing
- Soups
- Professional Use
- Updated Sep 24, 2024: We've updated the results to more accurately reflect the blender's performance. The score for Fibrous Ingredients (Small Batches) processing changed from 9.5 to 8.5 because of the blending time. The score for Fibrous Ingredients (Full Capacity) processing changed from 6.5 to 6.0 because of the very long blending time, and the texture score changed from 6.0 to 7.0.
- Updated Feb 15, 2023: Updated text to match Test Bench 1.0.
- Updated Aug 25, 2022: The score for 'Fibrous Ingredients (Full Capacity)' changed from 5.6 to 7.2 because a longer blending time results in a better texture. The 'Texture' score changed from 5 to 6 and the 'Processing' score from 8 to 6.5 because of the extra time required.
- Updated Jul 28, 2022: Converted to Test Bench 1.0.
- Updated Apr 16, 2021: Review published.
- Updated Apr 13, 2021: Early access published.
- Updated Apr 13, 2021: Our testers have started testing this product.
- Updated Apr 08, 2021: The product has arrived in our lab, and our testers will start evaluating it soon.
- Updated Apr 03, 2021: We've purchased the product and are waiting for it to arrive in our lab.
- Updated Mar 27, 2021: The product has won our suggestion poll, so we'll buy and test it soon.
Differences Between Sizes And Variants
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. 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.
| Model Number | Details |
| 640 | Two personal jars (2x 24oz) |
| 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, and we'll update our review.
Compared To Other Blenders
The Ninja BL642 is a full-size blender with a 72-ounce main jar and personal jars for smoothies. It performs similarly to the Ninja Professional Plus Blender DUO with Auto-iQ, but the BL642 model comes with three personal jars (rather than one) and has a slightly different selection of blending programs. That said, other Ninja blenders like the Ninja Mega Kitchen System and Ninja Foodi Power Pitcher System make a smoother blend with fibrous ingredients. It also doesn't come with any additional accessories, unlike the Kitchen System, which comes with personal jars and a food processor, or the Foodi, which includes a dough blade.
If you're still looking for a blender, try our lists of the best Ninja blenders, the best blenders for smoothies, and the best blenders.
The Ninja Blender Duo with Auto-iQ BL642 is better than the Ninja Detect Duo Power Blender Pro. The BL642 makes a smoother blend with fibrous ingredients, which is important for silky smoothies, and it's easier to use for thicker recipes like nut butter. It's also quieter when it's running.
The Ninja Blender Duo with Auto-iQ BL642 and the Ninja Professional Plus Blender DUO with Auto-iQ are similar blenders. The BL642 comes with a 72-ounce pitcher and three personal jars for single-serve smoothies, and the DUO comes with the same 72-ounce pitcher and only one personal jar. The DUO is quieter and makes a smoother blend with big batches of fibrous ingredients. Otherwise, they perform about the same.
The KitchenAid K400 is better than the Ninja Blender Duo with Auto-iQ BL642. The KitchenAid makes a smoother blend with fibrous ingredients like kale, especially when you're working with bigger batches, and it can hot blend. It's also easier to clean. On the other hand, the Ninja comes with personal jars and to-go lids for single-serve drinks like smoothies. It's also quieter when it's running.
The Ninja DUO and the Ninja Blender Duo with Auto-iQ BL642 are full-size blenders with personal jars for smoothies and have different strengths. The DUO makes a smoother blend with fibrous ingredients and has a juicer attachment. On the other hand, the BL642 is much quieter when running and also makes well-blended single-serve smoothies if you use its personal jars.
The Ninja Blender Duo with Auto-iQ BL642 and the Ninja Professional Plus Kitchen System with Auto-iQ perform very similarly but come with different jars. The Duo comes with a 72-ounce main jar with two or three personal jars, while the Kitchen System comes with a similar main jar, two personal jars, and a separate bowl and blade for food processing.
The Ninja Blender Duo with Auto-iQ BL642 and the Ninja Professional Plus Blender with Auto-iQ have a similar design and a similar performance in their 72-ounce main jars. However, the BL642 is better for making single-serve smoothies because it comes with three personal jars that you can use to make a well-blended smoothie with fibrous ingredients like kale. It's also somewhat quieter when it's running.
The Vitamix A3500 is better for most purposes than the Ninja Blender Duo with Auto-iQ BL642. The Vitamix has a significantly better build quality. It's better at processing fibrous ingredients and making nut butter. You can also use it to hot blend, and it's easier to clean by hand. However, the Ninja comes with smaller blending jars with resealable lids for making single-serve drinks like smoothies.
The Vitamix 5200 and the Ninja Blender Duo with Auto-iQ BL642 have different strengths, and you may prefer either one, depending on your needs. You can use the Vitamix blender for hot blending. Its main jar comes with a tamper and a two-part lid and has a significantly better build quality. In addition to its main jar, the Ninja has three differently-sized personal jars with matching to-go lids. It also makes crushed ice with a better texture.
The Ninja Blender Duo with Auto-iQ BL642 is better than the NutriBullet Blender Combo for most purposes. The Ninja has a better build quality. It can make snow-like crushed ice and is much better suited for processing hard ingredients like nuts. All of its components are dishwasher-safe. On the other hand, you may prefer the NutriBullet model because it can hot blend. It's much easier to clean by hand and makes a much smoother blend with big batches of fibrous ingredients.
The Vitamix Explorian E310 is a better full-size blender than the Ninja Blender Duo with Auto-iQ BL642. The Vitamix is much better at processing ingredients like kale in its main jar. It's also easier to use for tough tasks like making nut butter. You can use it for hot blending, and it's easier to clean by hand. On the other hand, you may prefer the Ninja because it comes with personal jars for blending single-serve smoothies. Its main pitcher has a bigger capacity and is a little better for crushing ice.
The Ninja Blender Duo with Auto-iQ BL642 and the Oster Pro 1200 have different strengths. The Ninja is sturdier and quieter and comes with three personal jars for single-serves instead of one. However, the Oster does a better job of processing big batches of fibrous ingredients in its main jar. It can also hot blend, making it better for big batches of smoothies or pureed soup. It's easier to clean by hand, and its main jar is made of glass, which is less prone to scratching and discoloration.
The Braun TriForce Power Blender is better for most purposes than the Ninja Blender Duo with Auto-iQ BL642. The Braun has a better build quality and blending performance for most recipes, like processing small and big batches of fibrous ingredients and making nut butter. It can also hot blend. However, the Ninja comes with three personal jars for single-serve smoothies, instead of just one.
The Blendtec Designer 725 is better than the Ninja Blender Duo with Auto-iQ BL642 for most purposes. The Blendtec is sturdier, easier to clean, and makes a smoother blend with fibrous ingredients like leafy greens and fruit in its main jar. On the other hand, it only comes with one jar for single-serves, while the Ninja comes with at least two. The Ninja is also much better for making thicker blends like nut butter or hummus.
The Vitamix Explorian E520 is a better blender than the Ninja Blender Duo with Auto-iQ BL642. The Vitamix is studier, offers more speed settings, and is easier to clean by hand. It makes a smoother blend with fibrous ingredients like kale and it's easier to use for thick recipes like nut butter. It can also hot blend. On the other hand, the Ninja comes with personal jars that can blend small batches for something like a single-serve smoothie faster.
You may prefer either the Ninja Blender Duo with Auto-iQ BL642 or the Ninja Foodi Cold & Hot Blender, depending on what you're looking for. The Foodi can hot blend and heat ingredients. It makes a much smoother blend with fibrous ingredients like kale, so it's more suitable for recipes like soup. On the other hand, the Duo comes with three personal jars with resealable lids and makes a well-blended smoothie much faster.
The Ninja Blender Duo with Auto-iQ BL642 is better than the Ninja Foodi Power Pitcher SS201. The BL642 makes a smoother puree with fibrous ingredients like fruit and broccoli, especially when blending small batches, because it comes with personal jars. The Foodi doesn't come with any personal jars, but it comes with a dough blade in addition to its regular blade assembly.
The Ninja Blender Duo with Auto-iQ BL642 is better than the Ninja Foodi Power Pitcher System for most purposes. The BL642 comes with more personal jars for recipes like smoothies and protein shakes and does a better job of blending small batches of fibrous ingredients. It has a better build quality. However, the Foodi's 'Smoothie Bowl Maker' jar makes it very easy to use for thicker recipes like nut butter or dip.
The Vitamix A2300 is better than the Ninja Blender Duo with Auto-iQ BL642 for most purposes. The Vitamix is sturdier, is easier to clean, has more speed settings, and has a better blending performance for most recipes. However, the Ninja is a full-size blender with personal-sized jars included, and it's a little better at crushing ice.
The Ninja Mega Kitchen System is better than the Ninja Blender Duo with Auto-iQ BL642 for most uses. The Kitchen System makes a smoother blend with big batches of fibrous ingredients when you're making multiple servings of smoothies. It also comes with a food processing bowl. However, the BL642 comes with three personal jars for single-serve smoothies instead of two. Their to-go lids are resealable, so you might prefer that model if you plan to use the personal jars as travel cups.
The KitchenAid Diamond is better than the Ninja Blender Duo with Auto-iQ BL642. The KitchenAid makes a smoother blend with fibrous ingredients, whether working with small or big batches. It's also easier to use for thick blends like nut butter, and its blade design makes it easier to clean by hand. On the other hand, the Ninja comes with at least two personal jars for single-serve smoothies in addition to its 72-ounce pitcher. It also feels better built.
Test Results
It's a bulky full-size blender. It's best stored on your kitchen counter or in a large cupboard, but you can also remove the main jar for easier storage.
It's very well-built. 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.
The main jar has a big 72-ounce capacity. This model comes with three additional personal jars with different sizes.
The jars are made of plastic and are dishwasher-safe, along with the lids and blade assemblies.
The main blade assembly is similar to other Ninja blenders, like the Ninja Mega Kitchen System. 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 lid for the main jar is made of plastic and has to be properly aligned to clip into place. There's a small window-like spout that you can use for pouring, but it's not a two-part lid and isn't intended for adding ingredients while blending.
The power cord will 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.
- 72oz blender pitcher with lid
- Ninja BL642 motor base
- Stacked blade assembly
- 32oz jar
- 24oz jar
- 18oz jar
- Pro extractor blade assembly
- 3x to-go lids
- Manual
- Recipe book
It's fantastic for small batches of fibrous ingredients. It makes an almost completely smooth blend with fibrous ingredients like kale. However, you have to follow the 'Ultra-Blend' program with about 30 seconds of manual blending on high for the best results. Some blenders can achieve similar or better results faster.
This blender is okay at processing big batches of fibrous ingredients. If you fill the 72-ounce jar to its full capacity, it makes a somewhat grainy blend with ingredients like kale. It also takes nearly 10 minutes of blending to get the best possible results. Since it takes such a long time, it's easier to manually blend, beginning at a lower speed and ramping up to blend on high for most of the process. There's also a 'Frozen Drinks/Smoothies' blending program that works with the main jar, but you need to run it several times for the best results.
The Ninja BL642 is fantastic for crushing ice. It makes truly snow-like crushed ice very quickly.
The Ninja BL642 makes very smooth, spreadable nut butter, but it's not the easiest to use for that purpose. It takes a little under seven minutes of blending to fully process the ingredients, and you need to stop the machine partway through the process to remove the lid and scrape the sides of the jar. It takes a little longer than with the similar but slightly more powerful Ninja Mega Kitchen System but produces similar results.
It's not particularly loud for a blender. Like almost all blenders, though, it's not pleasant to stand next to for very long while it's running.
There isn't a huge difference between the lowest and fastest blending speeds, even compared to more budget-friendly blenders like the KitchenAid K150. It's a typical design for Ninja blenders, and means you can't slowly ramp up the speed or make small adjustments depending on the recipe.
It has a few manual blending modes and automatic blending programs. There are three speed presets and a pulse button that pulses as long as you're holding it down. The 'auto-iQ' blending programs automatically pulse and blend for a set amount of time before the blender stops automatically. Most of the blending programs are only available with either the main pitcher or the personal jars.
- Puree
- Frozen Drinks/Smoothies (main jar only)
- Nutri Ninja Blend (personal jars only)
- Nutri Ninja Ultra Blend (personal jars only)
It's not easy to clean, mostly because of the blade design. Like most full-size Ninja blenders, the blades are removable but are very sharp and have a spiral design, so it's easy to cut yourself. You have to be careful and use a brush to clean any residue off the blades. The lid's spout opening and the ridges around its seal can also need extra scrubbing.