Open a spreadsheet such as Excel. If you don't have access to one, use the spreadsheet at Google Docs (docs.google.com). You'll need to create a free account and then sign in. Then from the "New" menu in the upper-left, choose "Spreadsheet."
Save the spreadsheet under a meaningful title. This example uses "One Week in Seattle." Don't forget to save frequently so you don't lose any information.
In row 1, enter the following headers for each column Description, Cost, Days, People, Days, and Totals.
In column A, under Description, enter the following categories. (You can add other categories as needed.)
Flight
Hotel
Meals
Entertainment
Transportation
Souvenirs
Misc.
Format the column and row headers as needed to make them easier to read. Then adjust the column widths to fit their contents. This example changes the fonts to bold and narrows some of the columns.
Estimate your daily cost. Under the Cost column, enter your estimated daily cost per person for each of the categories. Since hotels typically charge per night and not per person, put the nightly charge in the Hotel category. For flight, enter the airfare per person. If available, format this column as currency.
Put the number of vacation days in the Days column by each category. For our example, let's assume 7. Be sure to include the departure and arrival day. However, for the Flight category, use 1. For Hotel, put in the number of nights, which in our example, is 6.
Enter the number of travelers in the People column by each category. In our example, the number is 2. However, in the Hotel category, use 1, since the room charge is for 2 people.
Calculate the price by entering a formula in the Totals column multiplying the Cost by Days by People. For example, in the Flight category, enter the formula "=B2*C2*D2" into the Totals cell. Copy this formula to the other categories in the column.
Add any one-time expenses not covered in the categories. Put the name of the expense under the description and the cost under Totals, without any formulas. Our example uses "Salmon Show" under Description and "100" in the Totals column because that is the price for two people.
Skip a few blank cells after the last number in "Totals," in case you need to add last-minute expenses. Enter a formula such as "=SUM(E2:E12)" in the cell of that column. In this example, the total budget is $3,280.
