For whole live lobsters, the usual rule is about 7–8 minutes for the first 1–1.25 lb, then roughly 2–3 extra minutes for each additional pound once the water has returned to a strong boil.

Quick Scoop

Here are reliable boiling times for hard-shell lobsters (per lobster, in vigorously boiling, salted water, timing starts once the water returns to a boil):

  • 1 lb lobster: 7–8 minutes.
  • 1.25 lb lobster: 8–10 minutes.
  • 1.5 lb lobster: 9–12 minutes.
  • 1.75 lb lobster: 12–13 minutes.
  • 2 lb lobster: 11–15 minutes.
  • 2.5 lb lobster: about 18–20 minutes.
  • 3 lb lobster: about 22–25 minutes.
  • 5 lb lobster: about 30–40 minutes (check early to avoid overcooking).

A simple way to think about it: boil about 8 minutes for a 1 lb lobster and add about 2–3 minutes per extra pound.

How to tell it’s done

Time is a guide, but doneness is about the meat:

  • Shell is bright red, antennae pull off easily.
  • Meat in the thick part of the tail is opaque white, not translucent.
  • Internal temperature in the tail is around 135–140°F (57–60°C) if you use a thermometer.

Let the lobster rest a few minutes after cooking so the juices redistribute in the shell before cracking in. Information gathered from public forums or data available on the internet and portrayed here.