There is no single ‘good’ ROAS. A good ROAS can vary by campaign, industry, or even marketing goals. There are even some cases where a lower ROAS might not be a bad thing. However, in general, a ROAS of 4:1 or higher indicates a successful campaign.
For More Information Please Refer: https://adespresso.com/blog/roas-how-to-maximize-return-on-ad-spend/