This formula could have saved me from a $1,000,000 mistake...

Ever have multiple sums & subtotals in your model? Like this:

cost 1

cost 2

cost 3


subtotal 1

cost 4

cost 5

cost 6


subtotal 2


Grand Total =SUM(subtotal 1, subtotal 2)

I encounter it a lot in a Headcount schedule, for example:

salary 1

salary 2

salary 3


total salary

benefits 1

benefits 2

benefits 3


total benefits

bonus 1

bonus 2

bonus 3


total bonus


Grand Total Wages =SUM(total salary, total benefits, total bonus)


One time, I was helping a client build a headcount schedule.

We added "bonus expense" at the last minute.

And I FORGOT to update my "Grand Total" SUM formula at the bottom.

(basically, I left out the "total bonus" piece)

Which meant there was a $1,000,000 cost MISSING from our budget.


Fortunately, I caught it "soonish enough," (sort of...)

told the client, and thankfully didn't get fired.

(and sprinted to Google for a future solution)


You know what could have saved me?

🟢 =SUM(range)/2

Specifically — right below my "Grand Total" line.

So, more accurately:

🟢 =SUM(my entire headcount schedule)/2 𝙢𝙞𝙣𝙪𝙨 the Grand Total

(↑ should always equal $0)


This Excel 101 formula 𝐝𝐨𝐮𝐛𝐥𝐞-𝐜𝐡𝐞𝐜𝐤𝐬 𝐦𝐲 𝐆𝐫𝐚𝐧𝐝 𝐓𝐨𝐭𝐚𝐥.

So, in my example above...

When I added that Bonus Schedule at the last minute,

The =SUM(range)/2 formula would have told me —

"Yo! You forgot to update your Grand Total formula!"

And saved me from this mistake.


So, next time you're building a schedule like this, try it!

You just grab the whooooooooooole range, and divide by 2.

90% of all spreadsheets contain errors.

Remove one from yours.


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