I was looking to get some help with my federal quarterly estimates this September.

* My W2 income is 36k/year
* My 1099 income (started 2 months ago) is around $1000/month

How do I calculate my quarterly estimated payment for this coming quarter? I've searched online but I'm still confused about the income tax part of the equation, mainly because I have the W2 income on the side and I'm not sure how that factors in. 

Any help would be appreciated.