If you want the protection of Avast or Bitdefender, but don’t want to pay for security software, then both programs have a respectable free tier. There’s not much to draw the two apart, as they both offer virus scanning and simple malware defense. Arguably, Avast Free is slightly better than Bitdefender Free, thanks to a brilliantly simple interface and a little less pushiness at the upsell to paid-for plans. Both work well, however, at protecting a single device against malware threats.