Garrett ACE 400i Metal Detector Review

The Garrett brand has earned itself quite the reputation among metal detectors. The ACE model line, in particular, has proven to be quite a handy little detector. With the Garrett Ace 400i, the company has claimed to have produced the “king of ACEs”.

The reviews of the product have been quite positive, so let’s see if this metal detector has really merited this considerable title. This is a well-known product because it’s reliable and affordable with a good reputation.

Garrett 400i metal detector
  • Total Weight : 2.6kg or 5.8 pounds
  • Batteries: 4 AA 20+ Hour Battery Life
  • New Iron Audio: allows user to hear discriminated iron
  • New Digital Target ID: 0 to 99 scale offers target information
  • New Adjustable Frequency
  • New! Includes Pulse-Width Modulation audio: sharper, more responsive audio

Design and Appearance of the Garrett ACE 400i

In terms of the design, the Garrett ACE 400i looks a lot like the other ACE models with the exception of a cross-shaped coil. This metal detector consists of a shaft, a PRO Performance 8.5″ x 11” DD coil, and a 400i control box. The shaft ends in a comfortable arm rest that comes equipped with an adjustable Velcro strap. There is also a coil cover available which can be snapped on with ease.

This model is also armed with the Garrett Clearsound Easy Stow Headphones with an inline volume switch. The 400i comes out of the box in three separate parts with the coil, the straight shaft, and the s-shaft separate from one another. You will need no other tools than the ones provided with the metal detector to put it together.

With your arm in the armrest, it is very easy to man the buttons. You are able to easily adjust the controls with just the movement of your thumb alone. The digital display allows you to keep careful track of all of the functions of the metal detector.

In addition to the comfort factor, the other advantage with the ACE 400i is the weight. Weighing in at just 1.32 kg, you are definitely not going to get tired carrying this detector around. But, it is not recommended for kids, see the best metal detectors for kids here. It also has an adjustable length of 1.06 meters to 1.29 meters.

This is the ideal machine to take with you if you are planning on spending a considerable amount of time out in the field.

Buttons and Modes of the Garrett ACE 400i

Garrett-ACE-400iThe Garrett ACE 400i comes furnished with six different buttons. These are the Power/Iron Audio, Pinpoint, Frequency Adjustment, Discrimination, Sensitivity, and Mode. These are accompanied by a LED display on top. The LED display shows the Mode Indicator, Target ID Legend, Digital Target ID, Target ID Cursor, Lower Scale, Depth Indicator, Sensitivity Setting, and battery level indicator.

The metal detector can be powered by simply pressing the Power button for one second and then releasing it.

Using the Mode buttons, you can scroll through five different modes. These are:

  • Zero-discrimination: detects all types of metal
  • Jewellery: designed to find necklaces, rings, and bracelets while rejecting iron-based objects
  • Custom: to be programmed by the user with settings being saved. Start with discrimination pattern and then use DISCRIM along with Accept/Reject to customize the mode.
  • Relics: avoids iron while picking up objects with lower conductivity such as bronze, lead, and brass.
  • Coins: programmed to find most types of monies while rejecting foil and iron. Certain unnecessary objects such aluminium cans may be detected.

The Sensitivity buttons can be used to either increase or decrease the sensitivity of the metal detector. There are eight sensitivity levels present.

The Discrimination button is used in conjunction with the Accept/Reject button to ensure that trash is rejected.

The Power button also doubles as the Iron Audio button. By pressing this button, you are able to hear discriminated iron.

The Pinpoint button is used to help narrow the location of a possible object. It is pressed over the suspected location of a target.

Features and Performance of Garrett ACE 400i


The Garrett ACE 400i comes packed with a lot of new features for the ardent explorer. The first feature is the Iron Audio which allows the user to hear the normally silenced discriminated iron. This way, you will not be digging for undesirable objects. Even better, the mid-tone range can actually be altered. This way, different iron objects will produce different sounds allowing the user to distinguish between them. The iron resolution is stated to be at least twice as powerful as the ACE 250.

The other function is the Digital Target ID with a 0 to 99 scale. This allows the user to better identify the objects being picked up. There is also a higher frequency of 10 kHz, allowing objects with lower conductivity such as gold to also be detected. The frequency is also adjustable, meaning that there will less interference when using the ACE 400i. This model also comes equipped with a new Pulse-Width Modulation for more responsive audio.

The old features such as the pinpointing, coin depth, variety of modes, and sensitivity options are still as good as ever. Combined, these not only help you to find targets that you actually want, they also help to narrow down the location. All of these functions help to cut down the amount of time that it takes to find what you are looking for. The discrimination features reduce the likelihood of picking up non-metal items or other pieces of junk.

Pros and Cons of the Garrett ACE 400i


  • Incredible sensitivity
  • Greater distinction between iron objects
  • Fast recovery time
  • Great value for money
  • Good battery life
  • Lightweight
  • Comes with attachments


  • Audio volume cannot be adjusted on the machine – only on the headphones
  • The detector is less reliable around high mineralised soils

Is garrett ace 400 waterproof?

Yes and no, like any other tricky question. The coil is waterproof, while the box of the metal detector isn’t. It’s really good to make sure that water doesn’t get nearby the box to not risk and damage the electronic circuit.

Final Verdict
Everyone seems to agree the Garrett ACE 400i really can do no wrong. This detector really is an improvement on all of its predecessors. In addition to having great sensitivity, users are also now able to distinguish between different types of iron. One of the major advantages is the price – for all the advanced features that you get, it really is somewhat of a bargain.

Not to mention, you actually get additional attachments to go along with the metal detector. This is definitely a nice little surprise for the price you are paying. The complaints about this detector are far and few. In fact, you are pretty much scraping the barrel.

If you want a high-quality, dependable metal detector, the Garrett ACE 400i is definitely the one that you should be counting on. You will certainly not regret your decision.

I’m one of the founders of this blog. A 32 yr old from Lincolnshire & proud father of 3 beautiful children. My first metal detector was a garret ace 150 but I am currently using the Garrett ace 400i. My best find was a roman coin. Feel free to ask me any questions.

Click Here to Leave a Comment Below

ken - February 12, 2017

This detector is a very good machine it is better when you listen to the tones rather than looking at the id.If you only get one bell tone and not a double bell tone i would advise you
still dig i have had some deep coins using this method.

    Steve Race - March 2, 2017

    Thank you Ken for stopping by and contributing to the post.

    Muchas gracias amigo 🙂

    Peter Hughes - March 28, 2021

    I just bought a new coil for my ace250, a nel tornado, any chance it will work with the 400i

      Samantha Hughes - May 4, 2021

      I have the tornado nel and since putting it on I’ve pulled out an Elizabethan silver hammie half groat and a gold gilded button which was about30/40 cm down

    Dave Radford - September 3, 2021

    Hi Steve, I’m presently using a Garrett AT PRO, my issue is the weight of this machine which is 6.5lbs I’m using an easy swing harness which takes the weight but after swinging for 2 to 3 hours it’s tiring, the 400i is 5.8lbs I think ? So that’s not far off another lb less, I like the digital read out on the AT PRO and that it’s waterproof, is there a waterproof version of the 400i ? I know with the 400i the hood keeps the machine water proof and the coil etc is too. I’ve heard lots of good reports about the 400i is it as good as they say?

kenneth rawcliffe - March 2, 2017

You are very welcome steve

Mario - March 18, 2017

How do you think works on The Beach?

    Steve Race - April 17, 2017

    Hi Mario,

    Thanks for stopping by.

    The 400i is waterproof and is suitable for dry beach and careful fresh water detecting. It comes with a waterproof submersible searchcoil but the machine itself is not fully waterproof.

kenneth rawcliffe - April 17, 2017

You will need to keep reducing your sensitivity till the detector is more stable when detecting on wet sand then turn it back up when in the dry sand.


    Samantha Hughes - April 2, 2021

    Thank you for this advice. I. Completely new to detecting. I have the Garret Ace 400i and a 12″ tornado coil I bought as an Extr. I’ve been on the beach with both coils and in wet San it was constantly pinging

Yvonne - May 13, 2017

Thanks for the review – I’m looking at this model for use on the banks of the Thames in London, primarily because of the ability to screen out the huge amounts of iron and it is lightweight and waterproof. Is this the best choice for the terrain as the banks range from mud to puddles to wet sand and gravel?

    Steve Race - May 15, 2017

    Hi Yvonne,

    Yes, you are right this is one of the best models but keep in mind that the machine itself is not fully waterproof. And since you plan to use it in London where the humidity is pretty high and the weather is constantly changing, I suggest you use something better like Garrett AT Pro.

    It has better functionality and you could use it in water up to 3 meters so you won’t have a problem with it. Here’s my review on it

Kornel - July 6, 2017

Hi Steve,
Thanks for the nice blog. I am thinking to get the 400i as well. I would use it mainly for meteorite hunting. Is it good for that?

    Steve Race - July 28, 2017

    Hi Kornel,

    Meteorite hunting would be great with this model because you can distinguish different types of iron with it.

Gideon - July 28, 2017

Hi Steve
Will I be able to set the machine to detect all metal objects. Like when I’m on a beach somewhere , where people drop coins and jewellery all the time. I’m thinking off baying a Garret Ace 400I
Hope to hear soon from you

    Steve Race - July 28, 2017

    Hi Gideon,
    Garrett Ace 400i is a little more advanced for a novice, but I think you can get used to it pretty fast. This model is great when it comes to beach metal detecting, but please beware that it’s not fully waterproof, only the coil so you’ll have to make sure you don’t drop it in the water.
    You’ll have no problems with this model because it’s lightweight and it can find all sorts of jewelry on the beach.

peter collins - September 4, 2017

Hi Steve, what would be the best settings for the beach with this model please.

Regards Peter.

    Steve Race - September 6, 2017

    Hi Peter,
    When I’m on the sandy beach with my Garret 400i I’m usually going for the jewelry mode with sensitivity at maximum, because I got used to it and because I was lucky enough to find coins and some small rings in the past. It takes some practice to get used to it and to know how to make sense of the different frequencies but it will pay off once you get used to it.
    With what mode did you use it?

peter collins - September 7, 2017

Not been to the beach as yet, as i have only just bought the machine, i will report back when i have.


Alex - December 1, 2017

As an experienced 400i user I thought I would offer some guidance to beach hunting. As mentioned a few times the 400i works very well on dry sand above the tide line. Below the tide line is where you will struggle and I find the best settings are to set your custom mode to just the last four blocks ie 80 and upwards then reduce your sensitivity to 4 bars. Yes you will lose a fair amount of depth but you should be able to, as I do, still find lots of goodies.

    Steve - December 1, 2017

    Thank you Alex, that’s a great advice for our visitors!

Dave - January 6, 2018

I was told the 400i has only been out for 6 months?

    Steve - January 7, 2018

    Hi Dave, Garrett ace 400i is 2 years old and was released in 2016.

Julia - June 15, 2018

Hello Everybody!
Can i leave the coil protection cover on, while using the machine?
Thank you for the answer!
Bye from the netherlands

    Steve - June 15, 2018

    Hi Julia,
    Yes, that’s possible but it will affect the depth and the radius of your metal detector. I highly suggest you remove it while you do metal detecting. You can easily clean it, the coils are waterproof but I highly suggest you check that.

Mthabisi Ngwenya - October 4, 2018

Hello i want to buy a good gold detector. Can you help me with the right ones and at fair prices. Thank you in advance.

    Steve - October 8, 2018

    Hi Mthabisi, what range are you looking for your gold metal detector from starter, middle, professional?

Wayne knapton - October 14, 2018

Hi, I’ve never been metal detecting. Seriously thinking of getting this model and joining a club. I live in Dorset, England.


    Steve - November 1, 2018

    Get to action Wayne, this will be something that you’ll probably do for the rest of your life. Enjoying nature and spending some quality time with like-minded people, let me know how it goes!

Jeff - April 30, 2019

Hello Steve

I live in the Midlands, UK and was thinking about the Garrett 400i or the Fisher F44 which one would you recommend. I am new to metal detecting and want to search for old coins & jewellery.

    Steve - May 3, 2019

    Hi Jeff, I can see that you did your homework and you already know what to pick. I think both of the metal detectors are a great fit, I’m a big fan of the 400i but I heard only good things about F44 as well. My advice would be to pick the one with the best price for now in your area and you’ll be set or you can use the link from my blog for the 400i for a discount.

Damo - May 20, 2019

I was thinking of getting a 400i metal detector so I can search for some gold. Some of the areas I would visit have mineralized rocks and soil which are also rich in magnetite. I’m not sure if this detector would be able to differentiate? I’m keen to hear your thoughts.

Thanks in advance,

Mark Ireland - January 1, 2020

Could the headphones not be used as I wear digital hearing aids and would make it uncomfortable wearing the headphones.
I’m keen to hear your thoughts,possibly a connection between the detector and my hearing aids.

Darrell Texmo - January 25, 2020

For those who think that the 400i is too loud without the headphones, you can quiet the unit down by placing a strip of duct or Gorrilla tape on the speaker vents on the underside of the control box. If too quiet, just remove one strip of tape. Works awesome. High tones and shallow finds to all the new detectorists. 🙂

San - October 28, 2020

Till how much depth does it works ?

Benjamin - December 3, 2020

Hi Steve,

Trying to find out what the shaft weights, due to a medical condition I would like to get some weight of. In the beginning of your article you wrote it has a total weight of 2,6 kg and further down you wrote1,32 kg …

I’m looking at buying the MDattack carbon shaft, with only 534 grams in weight. So I wonder how much weight I will gain.

Btw thanks for your nice reviews!

    Steve - December 26, 2020

    Hi Benjamin,
    Thanks for pointing that out, it’s my error. With the accessories, it’s at 2.6kg and without them it’s weight is at 1,32kg.
    Also, I think you bring up a very good subject, in case you want additional weight loss what I can suggest is that you may also replace the coil with a carbon fiber one, the only problem with that will be the budget (it’s expensive) and they are actually hard to find.

Anthony - April 6, 2021

On opening the box I was surprised to find how poorly it was packaged, after spending almost £400 I expected something better than the universal tabs and cable ties holding it in place. unfortunately the flimsy build quality doesnt give me much confidence either😔I’m genuinely worried it may break in a stiff wind. All in all so far I would expect to have paid £150 at Argos for it. I’ve not tried it out in the field yet, but to many people 1st impressions and presentation mean more than the manufacturer seem to care.

Tara - April 6, 2021

I’m new to this and still wondering which Garrett is going to be the best one to start with. I’m only 5ft and need to know if these will be suitable for my height 🤣

I’m really liking the sound of the Ace 400i but not sure if it’s going to be too advanced for me.

shaun wolstenholme - May 12, 2021

Hi my name is shaun c….an you tell me is the 400 model ok to use on a beach..meney thanks.

    Steve - July 15, 2021

    Hi Shaun, yes it is a good detector for the beach.

Ian - January 9, 2022

Hi. Just read your concise review. My son out of the blue bought me a garrett 200i. Whilst I am a novice, I’m not sure I’m at all happy about going about fields with a device designed primarily for children. I am considering selling it to buy the 400i. Am I wasting my time and stick with the 200 or would you recommend me getting the 400i?

    Steve - March 4, 2022

    Hi Ian, I think the 400i is more advanced and pricier due to that, I would recommend you try the 250 or 300 first if you want.

Mike - March 17, 2022

I need to find a platinum ring somewhere in my garden. It won’t be very deep but may have been trampled on while I have been looking for it. What detector would be best?

I have been thinking about buying one in any case – before we lost the ring – sp this feels like the obvious time.

Many thanks

    Steve - March 22, 2022

    Mike, I would suggest getting the Minelab CTX 3030 for the platinum ring, it’s not a cheap detector so maybe you can borrow it from someone nearby.

Erdöl Biramen - June 5, 2022

Should I go for ACE 400i or for ACE Apex if the price difference between them is just €82,-?

    Steve - June 15, 2022

    I’d recommend you go for the 400i if that difference is not a problem for you.

ale.pen - September 21, 2022

its a shame the Garrett 400i armrest dose not have a bit more adjustment other than that a nice machine i have starter doing metal detecting

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