How much capacity does a specific bucket need?

I need to calculate how much capacity do I need for storing a data bucket with many documents

Take bucket(travel-sample) for example.

It shows the data on my couchbase web gui:

Bucket Name Item Count RAM/Quota Usage Data/Disk Usage
travel-sample 31569 74.3MB /100MB 48.6MB /77.2MB

Does that mean 31569 records need 48.6 MB capacity for storage?

Or there have any other issue need to be considered?

If I have 20K documents and may create about 5 indexes, the contents of the document are not big(2KB in txt).

Hello,

The Sizing guilde on the Official Documentation is very clear. Did you read it ? I think it covers pretty well this topic.

http://docs.couchbase.com/admin/admin/Concepts/bp-sizingGuidelines.html

Thanks, @heretyk

But I can not find the disk storage example, I want to know how much disk storage I need for storing many documents.

It mostly demonstrates the requirement of ram and other issues.