rental property calculators generate different assessment results - very confusing

Hello,

I’m learning how to assess single family rental properties with the intent for long-term buy and hold. Despite my efforts to keep all the input data consistent, I’m getting different rates of return from various rental calculators. I’m not sure which one is the most realistic.

BP Rental Property Calculator 

Rental Calculator: https://www.calculator.net/rental-property-calculator.html

Wealth Optimizer: https://www.rpmengage.com/wealth-optimizer

 Zillow: https://www.zillow.com/rental-manager/resources/rental-prope...

In addition to the ones listed above, I’ve also downloaded Excel spreadsheets from a couple of other sources. I'm unable to get consistent results for me to assess accuracy... 

If you are an expert in using rental property calculators and can help me discern which one might be the most accurate, please let me know. I would be very happy to schedule a Zoom meeting and compensate you for your time spent mentoring me on this subject.

Thanks,

Kevin