Partial 1031 Exchange- HELP!

[Eric Schwager]

I'm trying to compare a full cash out vs a partial exchange. I have a good idea on what my taxes would look like with full cash out, but not sure about the partial exchange. Need help to approximate the tax hit on partial. Here are some approximate numbers.

Original Purchase Price-$205K

Depreciation taken- $36K

Commissions on sale- $18K

Current Mortgage- $157K

Selling for $300K

Purchasing $125K at 70% LTV= New mortgage of $87,500 ($37,500 DOWN)

Assume 0% tax bracket ($36K or less taxable income)

Also, use 15% tax bracket.

My understanding would be boot on cash out and boot on mortgage difference.

Not sure how to figure approximate using either 0% or 15% tax bracket