# How do you calculate total Thrust and Specific Impulse for a rocket stage?

Given the stage has the following configuration:

Thrust
741.4 kN (Main)
47.1 kN (Vernier)
Specific impulse
297.999 s (Main)
288.999 s (Vernier)


How would I calculate the total thrust and specific impulse for the stage?

• Search for a recent question called "how does the rocket equation work when you have boosters", the answer gives the equation you need. Can't post link, on primitive device. Feb 15 '18 at 4:22
• You add the two thrust numbers together. Feb 15 '18 at 4:41
• @OrganicMarble I like the term "primitive device". I makes me think you are using a Timex Sinclair or a VT100 when in fact you are probably on something a hundred thousand times more powerful.
– uhoh
Feb 15 '18 at 6:05
• "I am endeavoring to construct a mnemonic memory circuit out of stone knives and bearskins" - Spock Feb 15 '18 at 11:15
• @OrganicMarble Ha! I was thinking of precisely the same thing! Although I would never have been able to come up with more than the last four words. Fascinating.
– uhoh
Feb 15 '18 at 15:00