• ## 21.3 Estimating the percentage of business use

This section is relevant only to the first method described in section 21.1.

End of attention

You calculate the percentage of business use of a car using the following formula:

 A B X 100

Where:

A = your estimate of business kilometres travelled by the car during the FBT year (or part-year, as the case may be).

B = the total kilometres actually travelled by the car during the same period.

The business use percentage and your estimate of the business kilometres must be entered into your business records by the due date for lodging your annual FBT return or, where you are not required to lodge a return, by 21 May.

### Estimating the business kilometres travelled in a logbook year

When estimating the business kilometres travelled in a logbook year:

• a logbook recording details of business journeys undertaken in the car must be kept for a continuous period of at least 12 weeks, as well as odometer records of total kilometres travelled during that period

• odometer records of the total kilometres travelled during the year must be kept

• you must estimate the number of business kilometres travelled during the full FBT year (or part-year if appropriate). The estimate must take into account all relevant matters, including the logbook records, odometer records, any other records you keep, and any variations in the pattern of business use throughout the year, for example, holidays or seasonal factors.

### Estimating the business kilometres travelled in a year that is not a logbook year

When estimating the business kilometres travelled in a year that is not a logbook year:

• you must keep odometer records of the total kilometres travelled during the year (or part-year if appropriate)

• you must estimate the number of business kilometres travelled during the full FBT year (or part-year if appropriate). The estimate must take into account all relevant matters, including the logbook records from the logbook year, odometer records for the current year, any other records you keep, and any variations in the pattern of business use throughout the year, for example, holidays or seasonal factors.

### Replacement cars

If you have replaced a car during the year, the replacement car may be treated as though it were the replaced car for the purposes of complying with the requirements outlined in section 21.5.

If you kept logbooks and odometer records during the year, or in a previous year, for the purpose of estimating a business percentage for the replaced car, that percentage may be transferred to the new car if it remains appropriate.

The transfer of a business percentage in this way is conditional on you recording in your business records the make, model and registration number of both cars and the date on which the replacement was made. These entries must be made on or before 21 May (or such later date as is agreed on for lodging the annual return). Odometer records kept for the cars during the replacement year must show details of the odometer readings of both the replaced car and the new car on the replacement date.