diff --git a/README.md b/README.md
index 5bfb003..f201912 100644
--- a/README.md
+++ b/README.md
@@ -12,6 +12,28 @@ For example. This was taken at 20:05 on 15th of December 2022:
 
 This is goes great with Conky and it allows you to display this on your desktop. As the past grows larger and times keeps ebbing away, this tool allows you to track this.
 
+## Usage
+```
+$ ./timepercentage.linux-amd64 --help
+Usage of ./timepercentage.linux-amd64:
+  -custom
+    	Display a custom range
+  -custom-start string
+    	Start of the custom range
+  -custom-stop string
+    	Start of the custom range
+  -day
+    	Display progress of the day. (default true)
+  -year
+    	Display progress of this year. (default true)
+```
+
+By default the tool prints the progress of the day and the year. A custom and optional date range can be specified by using the `custom`, `custom-start`, and `custom-stop` program flags. For example:
+```
+$ ./timepercentage.linux-amd64 --day=false --year=false --custom=true --custom-start="1990-01-01T12:00:00+01:00" --custom-stop="2030-01-01T12:00:00+01:00"
+▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▒░░░░░░░ 84.8765436%
+```
+The start and stop times have to be specified in the [RFC3339](https://www.rfc-editor.org/rfc/rfc3339) format.
 
 ## Building
-Checking out this repo and running `go build` should do this for you.
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+Checking out this repo and running `go build` should do this for you. Or run `build.sh` to build for other platforms.
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