Quoting Karen Kwok for Reuters Breakingviews

Simon Willison Blog
Generative AI

Anthropic defines “run-rate revenue” in two parts. Use the last 28 days of sales ⁠from customers charged on a consumption basis and multiply it by 13. Then, multiply the monthly subscription take by 12, ​and add the two together. - Karen Kwok for Reuters Breakingviews, citing "a person familiar with the matter"