The husband filed a petition for modification of his final judgment of dissolution of marriage, seeking to reduce his alimony obligation. The trial court denied the petition, finding that the husband had faded to show a substantial change in circumstances.

The husband raises several points on appeal, only one of which has merit. He asserts that in paragraph three of the final order the trial court compared the husband’s current monthly expenses to the weekly expenses reflected on his financial affidavit of February 5, 1988. The result is that the court determined the husband’s expenses had voluntarily increased. A correct calculation would have reflected a substantial decrease. The wife concedes this mathematical error, but contends it is harmless error. We cannot agree. We are unable to determine to what extent this miscalculation influenced the trial court’s decision. We therefore reverse and remand for the trial court to redetermine its ultimate ruling, taking into consideration the husband’s correct expenses.

Reversed and remanded.