Business, tax and funding
fixed price
In short and in plain language
A fixed price is a price for a job that you agree on in advance.
The price stays the same, even if the work takes more or less effort.
So you can plan your costs. This works as long as the job stays the same size.
Extra requests are usually charged on top.
Definition
A total price for a job that is agreed in advance and applies regardless of the actual effort. It makes costs predictable as long as the agreed scope stays the same. Extra requests are usually charged separately.