I have a Enterprise org and my storage usage is more than that given to us. What is the soft limit in Salesforce for the storage limit to create the records when the data usage is full in the org or is their any formula with the help of which we can identify our soft limit for storage after the full utilization is done in the org.
100% is the soft limit, the hard limit is a little trickier to pin down. This other question, at 170%, is the highest I've ever heard.
Instead of asking how much you can bend the limits, I'd recommend starting to plan how you can get your org under the storage limit (or purchase more storage from Salesforce).
Salesforce is being nice, and not immediately cutting your org off. Don't abuse that or take it for granted. Take the time to get your org under control, or it will come back to bite you (in the form of sudden failure that will probably take days to resolve).
As you've correctly identified, it does depend on what edition of Salesforce you're using, but this is what's given to us from the docs:
For data storage, Contact Manager, Group, Professional, Enterprise, Performance, and Unlimited Editions are allocated the greater of 1 GB or a per-user limit. For example, a Professional Edition org with 10 users receives 1 GB, because 10 users multiplied by 20 MB per user is 200 MB, which is less than the 1 GB minimum. A Professional Edition org with 100 users receives more than the 1 GB minimum, because 100 users multiplied by 20 MB per user is 2,000 MB.
I believe data storage is calculated asynchronously, so your org's storage usage isn’t updated immediately if you import a large number of records, for example.
Additionally, Salesforce has a grace area above 100%, somewhere between 125-150% for most orgs & editions.