To determine what plan you can resize your Linode to, you need to first understand your current usage. The three biggest factors of your usage are generally RAM, CPU, and disk space.

Ram Usage

To determine your RAM usage, you'll need to run a program to collect usage data over time in order to get the best perspective. There are some commands that can be run to view your current memory usage, but usage may change at various times. Some of these commands that can be used to check memory usage include:

free -m
cat /proc/meminfo
vmstat -s
top
htop

CPU usage

To check your CPU usage, you'll want to review your CPU graph over the past month, and see if you're utilizing all of the cores that your plan has been allotted. When you look at the graph, it will show you usage based off of how many CPU cores your Linode has access too. 100% utilization being displayed is noting that 100% of 1 CPU on your Linode is being used. For example, if you had 8 cores of CPU available on your Linode, each core represents 100% CPU. This means that you could use up to 800% CPU. Keep in mind that if you are always using all of your CPU, it's likely time to upgrade to the next plan.

Disk Usage

To check the amount of data that you have, log into your Linode via SSH or Lish and run the following from the command line:

df -h

This command will tell you how much space is being used and how much is available. You can then resize your disk to a smaller size, as long as it has enough room to accommodate the amount of data you have on it.

How to resize your plan

If you've determined that your RAM, CPU, and disk space can fit into a smaller plan, you can then resize it. The following guide has step by step instructions on how to do so.

https://www.linode.com/docs/platform/disk-images/resizing-a-linode/