Hi, yes its possible to create a formula on the report - the following thread has a sample formula which you can edit as per your requirement: https://success.salesforce.com/answers?id=90630000000gxiDAAQ May 8, 2014
Is there a way to add custom formula fields in Salesforce?
This feature is sadly (and unbelievably too) not available in Salesforce. Following is a idea post for this feature, you may want to vote it. This will omit the need of adding custom formula fields for the sake of reports. As of now, custom fields are the way out.
How to create a formula with my date fields in reports?
In report builder there was one option to add formula field but to create a formula with my date fields is not possible. Show activity on this post. In reports, it is not possible to create a formula in reports which calculate date/date time difference. Currently having a field on object seems to be the only alternative.
How to categorize Records in a Salesforce report?
You can create something called ‘Bucket’ field in Salesforce. With Bucket fields you can categorize the records in the report itself and on the fly. You don’t need to create a custom field on the object for this.
How do I add a summary formula to a column?
Click the arrow next to Columns and click Add Summary Formula. In Search fields type and select Won [1], ensure Sum [2] is selected and click Insert [3]. Place the cursor in the formula after SUM and enter /.
Manpreet
Yes. Formula are not available in tabular reports but available for other report types. Formula can be only in number, currency and percent format.
Aman
Before adding a summary formula to your report, be sure to group report data.
Follow Along with Trail Together
Want to follow along with an instructor as you work through this step? Take a look at this video, part of the Trail Together series on Trailhead Live.
Summarize Your Data in a Whole New Way
Summary formulas are a great way to calculate additional totals based on the numerical values in your report. In addition to the standard summaries that we used in a previous step, you can add up to five summary formulas to summary and matrix reports to create calculated summaries of your numerical fields.
Verify Step
You’ll be completing this project in your own hands-on org. Click Launch to get started, or click the name of your org to choose a different one.
Can you create a bucket field in Salesforce?
You can create something called ‘Bucket’ field in Salesforce. With Bucket fields you can categorize the records in the report itself and on the fly. You don’t need to create a custom field on the object for this. For example, let say that if you are creating a report on Opportunity and want to categorize the opportunities in the buckets of ‘small’, ...
Can you create buckets in a report?
You can create a bucket field in the report and categorize opportunity records on the fly in report itself. And then once you have created the bucket field, you can also use this in a formula field in the report.