Sustainability is an important topic for digital humanities practitioners and funding agencies. As the recent NEH sponsored “Sustaining DH” series illustrates, strategies for sustainable development, dissemination, and preservation are critical if the “making” side of digital humanities are to persist. This paper details an ongoing attempt to develop a “sustainability index” for grant funded digital humanities projects. For the purposes of this paper, we define sustainability as the quality of being accessible/operable following a granting period. We focus on operability as our sustainability index is based on a qualitative analysis of projects that received NEH Digital Humanities Start-Up Grant funding from 2010-2017, specifically under the product type of “Web Resources” or “Computer Programs.” Based on our analysis, we aim to show which criteria increase the likelihood of a sustainable project as well as the criteria that inhibit a project from remaining sustainable.