How much disk space do heroku plans have?

You don't want to be uploading anything to Heroku, it has an ephemeral file system which is reset on restarts/deploys. Anything uploaded should be uploaded to a permanent file store like Amazon S3

https://devcenter.heroku.com/articles/dynos#ephemeral-filesystem

From How much disk space on the Dyno can I use? of the heroku help site:

Issue

You need to store temporary files on the Dyno

Resolution

Application processes have full access to the available, unused space on the mounted /app disc, allowing your application to write gigabytes of temporary data files. To find approximately how much space is available for your current Dyno type, run the CLI command heroku run "df -h" --size=standard-1x -a APP_NAME, and check the value for the volume mounted at /app.

Different Dyno types might have different size discs, so it's important that you check with the correct Dyno size

Please note:

Due to the Dynos ephemeral filesystem, any files written to the disc will be permanently destroyed when the Dyno is restarted or cycled. To ensure your files persist between restarts, we recommend using a third party file storage service.

The important part here is that it is not the same value for every plans and is possibly subject to changes with time:

Different Dyno types might have different size discs, so it's important that you check with the correct Dyno size

The correct answer is that it would appear you have 620 GB.

According to this answer: https://stackoverflow.com/a/16938926/3973137