What is a GB and how many MB are in a GB: A Mobile Data Guide

If you’re on the hunt for a new phone plan, then you’ve probably come across plans that are called something like “15GB” or “10GB,” and if you’ve looked into the fine print of unlimited data plans, you also would’ve seen something like “comes with 35GB of premium/high-speed data.” Without any knowledge of what a GB is, or how many MB make up a GB, it would be hard to understand what those plans offer and how you can use them. This guide will walk you through everything you need to know about data: What is a GB, how many MB in a GB, and how to measure data use.  

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What is a GB and a MB?  

A gigabyte (GB) and a megabyte (MB) are units of digital storage measurement. A MB is smaller than a GB and is often used to measure data usage by lighter apps like messenger, email, or your browser.  

How many MB are in a GB?  

There are 1,024 MB in a GB, but that number usually gets rounded down to 1,000. So, it takes approximately 1,000MB to use up one 1GB. You can use this chart on how much data common activities on your phone uses to help you determine just how much data you actually need:  

GB for mobile data/internet: What does it mean? 

A GB can get confusing because it refers both to the available data on a physical hard drive on a device and the available mobile data/internet usage set by a service plan.  

When looking over phone plans, GB is mentioned frequently, as it’s the unit of measurement of what most phone plans offer: data. Limited data plans will come with – you guessed it – a limited amount of data, such as 5GB, 10GB, or 15GB. All that means is that once you use up your limited amount, you don’t have any more data for the remainder of the billing cycle (unless you pay to top up). Unlimited data plans will also, in most cases, come with a limit of their premium or high-speed data. It may say something like 35GB of high-speed data in the fine print, which would mean that after that limit is reached, your data will still be available but at slower speeds for the remainder of the billing cycle.  

How does mobile data get measured? 

Simply put, your mobile data gets used up every time you perform an action on your phone that requires internet access. That would include streaming music, scrolling social media feeds, checking email, posting and watching videos, and more. You can check how much data gets used up by specific apps through your phone’s settings, but in general, streaming videos will take up the most data and depending on how much time you’re spending on social media apps, those could also be heavy data users.  

How to reduce data usage  

According to Ericsson, the average mobile data use in the U.S for 2024 was 22 GB a month. If you’re looking to reduce your data usage so you can save with a cheaper phone plan, here are some quick tips you can implement: 

1. Set apps to update only on Wi-Fi.  
   Check your settings and make sure that all apps are set to only update if you’re connected to Wi-Fi, so they’re not using up data without you even knowing about it.  

1. Turn on data saver mode for social media apps.  
   In each app’s settings (Instagram, Facebook, TikTok), you can enable a “Data Saver” mode, which will optimize the feed, so it uses up less data (lower quality of videos, turns off auto-play, etc.)  

1. Disable auto-download on messaging apps.  
   On messaging apps like WhatsApp, Telegram, etc., you can disable “auto-download” of photos, videos, voice messages unless on Wi-Fi. This protects you from using up mobile data to download any media files that are sent to you on these messaging apps.  

1. Download Content over Wi-Fi in advance.  
   Download media like songs, videos (YouTube), or movies/TV shows over Wi-Fi, so you can still access and enjoy them while on-the-go without using your data. 

Phone storage GB: What does it mean?  

When picking out a phone, you’re often presented with different storage options: 128GB, 256GB, 1TB, etc. These are indicative of how much physical space you would have on that phone – without Cloud storage – to store files, apps, media (pictures and videos), and any other downloaded content. Keep in mind that a video (especially if it’s recorded at high quality, like 4K) is going to be larger than a downloaded file like a PDF or a picture.  

How does phone storage get measured?  

Storage on a phone gets used up by the different apps and media files that are directly saved on your phone (not in an assigned Cloud storage). Note that the operating system itself also takes up storage, so when you buy a 128GB phone, you don’t start with 128GB of free space. The operating system and system data can take up to 20GB, so you’d be starting with 108GB.  

Here is a general guide to how many of each file type can be downloaded using the different storage options: 

Bytes Chart  

Megabytes and gigabytes are not the only units of digital storage measurement. To see where the other measurements fit, follow this simple chart.

 *A "bit" (short for "binary digit") is the smallest unity of digital information, and is the foundation of all digital communication and computing.