We are using create react app , we reduce the build size plugin,finally our project build size is 2.24 mb . but still my site take 3 to 5 sec.
How do reduce my build size?

This my build result:

File sizes after gzip:

  534.37 KB  build/static/js/34.75183bab.chunk.js
  353.29 KB  build/static/js/35.385449dc.chunk.js
  203.67 KB  build/static/js/36.e859badd.chunk.js
  71.32 KB   build/static/js/37.e235bf36.chunk.js
  62.37 KB   build/static/css/34.07a8fc6f.chunk.css
  38.53 KB   build/static/js/38.70b39141.chunk.js
  38.26 KB   build/static/css/main.d54e4d7b.chunk.css
  27.63 KB   build/static/js/3.3270243d.chunk.js
   ...etc 

The project was built assuming it is hosted at /.
You can control this with the homepage field in your package.json.

The build folder is ready to be deployed.
You may serve it with a static server:

  npm install -g serve
  serve -s build

Find out more about deployment here:

  bit.ly/CRA-deploy

[compress-create-react-app]:
Compressing build files...
    
Build compressed with gz
      The build size was reduced to 26% of its initial size, 6.26 MB was removed.
      2.24 MB instead of 8.50 MB
Build compressed with br
      The build size was reduced to 20% of its initial size, 6.81 MB was removed.
      1.69 MB instead of 8.50 MB
    ```