Commute Cost Calculator

Most people know what they spend on gas. Few have added the tolls, parking, transit fares and the wear on the car, and fewer still have asked how much salary it takes to pay for all of it after tax.

What This Workbook Does

• A month-by-month log of commute days, round-trip miles, fuel, tolls, parking and transit, with total miles and fuel cost calculated for you.
• A per-mile running-cost figure for the car itself — tires, servicing, depreciation — set by you and kept separate from fuel.
• The value of a pre-tax commuter benefit, counted as the tax it saves rather than as free money.
• Annual cost, cost per commute day, cost as a share of gross salary, and the pre-tax salary needed to cover it.

The pre-tax figure is the after-tax annual cost divided by one minus your marginal rate, because a raise is taxed before it can pay a toll.

How to Use It

1. Set the three figures at the top: your gross salary, marginal tax rate and per-mile vehicle running cost.
2. Enter commute days and round-trip mileage for each month.
3. Enter the fuel price and the fuel economy you actually get, not the sticker figure.
4. Enter tolls, parking and transit as you actually pay them.
5. If you put money through a pre-tax commuter benefit, enter the amount used.
6. Read the pre-tax salary needed to cover the commute — the number to carry into a job comparison.

What It Will Not Do

Vehicle running cost is a per-mile estimate you choose. A generous figure suits a newer financed car and overstates the cost of an older paid-off one, so set it deliberately rather than leaving the default.