I tracked business miles but not personal miles.

I tracked my business miles but not my personal miles. I also don't have records of my odometer readings from the beginning and end of the year, and I don't believe I have any receipts that might show me. Is there any way I can still report my business miles for actual expenses and estimate how many personal miles I drove legally? The TurboTax app is asking for my total miles driven but I only have my business miles driven...I'd appreciate some help. Thank you!