I figure when Mal and Cobb are in limbo, it is about 2 hours, 44 minutes real time.

From 5 minutes equals 1 hour of dreaming, we get that dreaming is a factor of 20 longer. And from 10 hours being 7 days on the first level, 6 months on the second level, and 10 years on the 3rd level, we are told that the same factor of of 20 is applied at each level. 6 months is roughly 20*7 days (actually 26 weeks) and we get that 10 years is 20 times 6 months. The actual time with the factor of 20 on each level is:

Real time of 10 hours is:

Level 1: 8.3 days (1 week is actually 7 days, duh.)

Level 2: 166 days (6 months is actually about 182 days)

Level 3: 3333 days, 9.25 years, 9 years, 4 months (I know, not quite 10 years)

Level 4: 185 years

We are never told the calculation to limbo, but I figure it must be counted as level 4 based on Saito's aging vs time on the plane, and same for Mal and Cobb.

So 50 years as a level 4 would be 2.73 hours, which would be 2 hours, 44 minutes. Also I know 8.3 days is not 7 days, and 165 days is 5.5 months, and 9 years 4 months is not 10 years, but I know it would be dumb in the movie if instead of quickly pointing out that it will be 7 days on level 1, 6 months, level 2 and and 10 years level 3, instead said we will be at level 1 for 8 days and hours, and 166 days at level 2, and 9 years and 4 months at level 3, it would sound dumb.

From 5 minutes equals 1 hour of dreaming, we get that dreaming is a factor of 20 longer. And from 10 hours being 7 days on the first level, 6 months on the second level, and 10 years on the 3rd level, we are told that the same factor of of 20 is applied at each level. 6 months is roughly 20*7 days (actually 26 weeks) and we get that 10 years is 20 times 6 months. The actual time with the factor of 20 on each level is:

Real time of 10 hours is:

Level 1: 8.3 days (1 week is actually 7 days, duh.)

Level 2: 166 days (6 months is actually about 182 days)

Level 3: 3333 days, 9.25 years, 9 years, 4 months (I know, not quite 10 years)

Level 4: 185 years

We are never told the calculation to limbo, but I figure it must be counted as level 4 based on Saito's aging vs time on the plane, and same for Mal and Cobb.

So 50 years as a level 4 would be 2.73 hours, which would be 2 hours, 44 minutes. Also I know 8.3 days is not 7 days, and 165 days is 5.5 months, and 9 years 4 months is not 10 years, but I know it would be dumb in the movie if instead of quickly pointing out that it will be 7 days on level 1, 6 months, level 2 and and 10 years level 3, instead said we will be at level 1 for 8 days and hours, and 166 days at level 2, and 9 years and 4 months at level 3, it would sound dumb.