Troubleshooting

My concern is  I only rent %40 of the house sq footage - basically one room. But the issue is there is no way indicating how many percent I am renting - I don’t want to pay capital gain in the future as this is my primary residence and since it is a small sq ft is rented - it is exempted from capital gain. On Turbo tax there is no way of showing the percentage and I don’t want to have problem in the future. In the past my accountant could separate personal and rental expense so it was easier to provide the rental property percentage…