SOS: How to build in the function in Excel Worksheet

Dear All,

I’m really a novice in creating certain functions in Excel worksheet. I am thinking of creating a scale fee formula in Excel worksheet but I have no idea how to start off.

The scale fee structure is as follows:

Amount Scale of Fees
For the first $ 150,000 1.0%
For the next $ 850,000 0.7%
For the next $ 2,500,000 0.6%
For the next $ 2,000,000 0.5%
For the next $ 2,500,000 0.4%

Should I key in any variable amount, the fee would be calculated automatically inside the Excel worksheet. For instance, for the amount of $2,700,000, the fee would be at $ 17,650 if calculated manually.

Therefore, how should I build in this function in the Excel worksheet? Many thanks in advance.