Summing across many tabs

cbridger 

Here's an example of a Pivot Table that takes data from a single year-long database and summarizes it by month. It's not exactly what you asked for, but it illustrates how one of Excel's more popular features (the Pivot Table) can be used with a single database to separate out the monthly data.

A common mistake of new Excel users--and an understandable mistake--is to think that it's all clearer if we tabulate matters on separate monthly sheets. But that actually makes it harder for Excel to do what it can do very well, which is to take a single database and extract monthly (or quarterly, etc) data for summary reports. We tend to mimic the paper-based method of record keeping, which made sense when recording data on big manual accounting sheets...but interferes with the computer's ability to extract meaningful summaries.

cbridger 

As a basic Excel user, you probably have created a design that could itself use some modifications to work more efficiently. I'm going to guess (not a wild guess) that each tab represents a month, and that each column for which you want to show the totals is something like "Expenses" and "Income" or "Deposits" and "Withdrawals"

Let me ask you if you already do totals on each column on each tab? If you do, are those totals all in the same cell on each respective tab?   If so, a straightforward way to get the totals is a formula like this (as shown in the attached sample sheet). For all twelve, you'd just extend that same system.

=Jan!A30+Feb!A30+Mar!A30

There are easier ways to do this, but for a basic Excel user, this may be the most straightforward.

An even better way would be to learn how to create a single database with all of those monthly transactions in a single table, on a single tab, and then use Excel features such as the Pivot Table to extract monthly data, including totals. This lets Excel do the heavy lifting.