Fish Finder Screen Size: The Ideal Screen Size (2024 Guide)

When you’re looking to buy a fish finder, choosing the right fish finder screen size is one of the biggest decisions you’re going to have to make. After all, if you can’t see what the unit is trying to show you, it’s pretty useless, right? But a bigger display means spending a lot more, so where is the balance?

I have used finders with tiny screens and it’s not easy, it actually becomes more of a frustrating tool than a useful one as you can’t really see what it’s trying to show you.

Here is a guide to picking the right fish finder screen size for your finder so you don’t have to live through the frustrations of squinting at a tiny screen or burn a hole in your wallet by buying a big one either.

Scroll down to see what I have whipped up to help save you both time and money.

What are the common screen sizes for fish finders?

Fish Finder Screen
Fish Finder Display

Before we dive into more details, let’s first look at what the market has to offer us in terms of fish finder screens so we know what options we have.

The fish finder basics tell us that sizes range between around 4 inches up to 12 inches, and this is across all the major manufacturers including Garmin, Lowrance, and Humminbird.

This is quite a big range as a 4-inch display would be considered on the smaller side and a 12-inch display a larger screen. But what does 4-inches actually mean?

How are fish finder screens measured?

The actual fish finder screen size is measured along the diagonal not from side to side. This means that if a fish finder’s screen is labeled as 7 inches, it will be 7 inches from the bottom left corner to the top right corner or the bottom right corner to the top left corner of the screen.

If it was 7 inches side to side, it would be a lot bigger than 7 inches along the diagonal.

What are the benefits and drawbacks of different screen sizes?

Fishfinders on a Table
Fishfinders on a Table

Different display sizes, big or small, all come with some positives and some negatives too, mainly relating to battery life, depth of usability, and price.

How does screen size affect battery life?

I’m sure you will have already worked out that a smaller screen will use less battery than a larger one, as more battery power is required to light up a larger area on a bigger display.

To answer how it affects battery life, we first have to work out what battery life means. 

  • Some models will run off a rechargeable battery within the unit.
  • Others you’ll have wired to the battery on your boat which is being recharged by the engine/solar panels.
  • Some units, if you’re say kayak fishing, will be wired to a battery that isn’t being recharged.

If your battery is being recharged while you’re fishing on your vessel, it’ll be less hassle to deal with as you don’t need to worry about your unit’s display size using up your battery life, as it’s being constantly charged.


If you’re running it off a battery that isn’t being recharged like with portable models, then be sure not to choose too big a display as the last thing you need is the battery dying while you’re trying to catch fish.

How does screen size affect usability?

This is a question many anglers contend with when fishing for a fish finder or fish finder GPS combo as.

All an angler want’s is a fish finder they can afford but still use effectively. 

The technology used in fish finders work by imaging sonar (sound navigation and ranging) meaning a transducer sends sound waves that are reflected by everything in the water column including any drop offs, river or weed beds, small or big fish, debris, or underwater structure, then collected, and put on an imaging display for you to see.


If the screen is too small, all the images your device will create including fish ID, water depth, big fish, fish of the same size, and different sizes are stuffed into a narrow slice rather than across a large screen.

This does make the data a little harder to read and understand when compared to looking at a big screen with brighter returns. It may be hard to see a thicker band of yellow color, like a hard bottom indicator for example, if there is no room for detail.

If you’re good at reading a fish finder, you can manage with a 4-inch display, but it would always be easier on a 7 or 10-inch display in comparison especially if it has a split screen mode.

How does screen size affect the price of fish finders?

The fact is, the bigger a fish finder screen the more expensive it will be.

This is because a unit with a bigger screen requires more materials to make, and modern fish finders with bigger screens tend to have more features such as traditional sonar with a CHIRP sonar cone, down beam, side scan, GPS, customizable color palette, and more.

This is why the concept around finding the right finder for you often comes down to picking a fish finder with a big enough screen that is still within your budget.

What is the best screen size for boats?

Fishfinder Mounted on a Boat
Fishfinder Mounted on a Boat

If you’re interested in finding a fish finder for your vessel, you don’t have to worry about things like battery life or portability when thinking about screen size.

The finder and transducer will be mounted to your boat and the battery will be recharged by the engine. There are different types of transducer and mounting can differ depending on your transducer. If you have no idea which type of transducer is best suited for your boat, click here.

The best screen size for any vessel in my opinion is the largest one within your budget that can be mounted onto your center console or dashboard.

Lowrance, Garmin, and Humminbird make all their models’ screens in various sizes, so you’ll be able to get the features you want with a screen size that works for you.


I’d say nothing smaller than a 7-inch screen size for a boat is ideal.

What is the best screen size for portable fish finders?

Portable finders are traditional sonar units designed to fit in your pocket, so you don’t want the screen size to be too big or too small that you can’t see the fish on the traditional sonar readings.

Also, a big screen will drain the rechargeable battery.


The smallest screen size you should consider is 4 inches and maybe go up to 5 inches at the most so the units aren’t a bit too heavy to carry around with the transducer and don’t run out of battery too quickly.

What is the best screen size for a kayak?

Kayaks are a little tricky as they are not boats, but you will go a similar distance to fish in a kayak or to similar sites, at least, that you would in any other watercraft.

This means you want the same sonar technology as you would in a boat that shows you the depth, fish, and more.

The main difference between a kayak and a boat is that, unlike a boat, your kayak doesn’t have an engine to recharge the battery that will run your fish finder.

Battery Life

But, you will have a marine battery running it, not a rechargeable one, so you’ll have more battery life to play with compared to a portable model.

This means you need to pick a screen size that you can still see the depth and fish on like spotted bass in the form of small ovals while ensuring it’s not too big to drain the battery. A screen size of 5 – 8 inches is what you need.

Fish Finder Size Comparison

How Big Is Your Fish Finder?

From Visually.

The point of this section is to give you an idea of fish finders’ display sizes compared to device display sizes you are familiar with, like iPhones, iPads and laptops.

A standard laptop display is 13 inches, a standard Ipad display is 9.7 inches, and a standard iphone 7 display is 4.7 inches.

If you imagine the fish finders, the smallest display you’ll get is around the size of an Iphone, a medium sized one is a little smaller than an Ipad, and even the largest fish finder will be smaller than a laptop.

Display Size vs Using The Split Screen Feature

Depending on the model of the fish finder you choose, like the Lowrance HDS, you might be able to split the screen to see your sonar image on one side, and say your GPS on the other while you’re fishing.

Which is a useful feature as you can find productive sites by seeing your location and what’s underwater at the same time.


The bigger the screen the better when it comes to splitting.

When the screen splits, it takes the image you’re seeing from being a thicker band to a very slim one, making it harder to read your location and see fish at the same time.

To help you visualize, here’s a video on how a split screen setup can be customized

HDS Live Split Screen and Customisable Buttons

Are plotter & sonar images reliable on smaller displays?

Yes, plotter and sonar images are just as reliable no matter what size screen you’re looking at the image on. The fish finder is certainly not going to show you things that aren’t there.

The challenge comes with seeing the details. On a larger screen you will notice more while on a smaller one, the details will be harder to see.

Sounding Out

Thanks very much for reading my article, I trust you enjoyed it and found it useful.

Picking the right screen size for your fish finder is very important to being able to use it effectively but at the same time you have to balance it with affordability, and I hope this article has helped.

Please share the article with your fishing friends as we all need help with this kind of tricky topic. You might also want to learn about fish finder fish arches or transducer cone angles.

Thanks again for reading and check out some of our other articles around fish finders, from Garmin to Lowrance, or if you want to check out the best fish finders on the market right now, click here.

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