thank you very much for the answers @armagheddonsgw: Yes i mean the highest altitude my ship can potentially reach. I asked this question because of the contracts "test xx at xx altitude". I thought there should be a easy way to calculate how much boost i need to reach, for example 11 000 m. @Cerberus738: Thank you, but i focused on my question more at altitude on Kerbin. But i guess soon i will need the deltav for the travels in space. I already found a useable map for this problem, but so far i cant find a calculation for altitude on Kerbin. Thank you again. Seems i have to experiment and remind that i should stay always below 4500 m/s.