A few months ago, a16z released a blog post on how to value your startup. Here are a couple TL;DR takeaways:
Public markets provide the best basis for recalibrating private growth valuations because public markets tend to see the effects of decreased valuations first.
Downturns hit different sectors differently, making it important to look at relevant public companies to best gauge where you stand.
In order to estimate where you stand, the article also outlines 3 steps:
For simplicity, we've created a calculator here to figure out your own valuation.
 The a16z article users NTM (Next Twelve Months). We use LTM (Last Twelve Months) because it's easier data to fetch.
 If your revenue is small, this probably is not going to make a whole lot of sense.