Critical Velocities
Body:
Gravity: m/s2
Escape: km/s
Altitude: km
Orbit: km/s
Engine Calculator
Payload tonnes
Engine tonnes
Fuel tonnes
Exhaust-Velocity km/s
Efficiency %

Delta-V km/s ln(Start-Mass/Dry-Mass) × Exhaust-Velocity
Activator g Fuel-Mass × (16 / 18)
Hydrogen g Fuel-Mass - Reaction-Mass
Kinetic Energy Joules Propellant-Mass × Exhaust-Velocity2
Reaction Energy Joules Reaction-Mass × Energy-Density × Efficiency

Based on the Tsiolkovsky (Циолковский / Tsee-ohl-KOV-skee) rocket equation, basic physics formula plus some wacky assumptions to produce plausible exhaust velocity values for speculative engine types.

Note that the NASA space shuttle weighed about 75 tonnes dry with up to 30 tonnes of cargo (source) and used H2-O2 engines with an exhaust velocity between 2.5 km/s for the booster rockets and 4.4 km/s for the main engine (source).