Estimate ideal rocket propellant mass for a target delta-v using the Tsiolkovsky rocket equation. Enter dry mass, effective specific impulse, required delta-v, and an additional propellant reserve. The calculator returns loaded propellant, ignition mass, and mass ratio for a single idealized stage, supporting quick feasibility checks before detailed trajectory and tank sizing.
Loaded propellant includes the selected reserve on top of the ideal rocket-equation requirement. Ignition mass equals dry mass plus loaded propellant; reserve propellant is shown separately.
This single-stage ideal model excludes gravity and drag losses unless they are already included in delta-v. Confirm that dry mass includes tanks, engines, payload, and unusable residuals as your project defines them.
For 1,000 kg dry mass, 3,000 m/s delta-v, 320 s specific impulse, and 5% reserve, the ideal mass ratio is about 2.6012. Ideal propellant is about 1,601.23 kg and loaded propellant is about 1,681.29 kg.
Include every mass that remains after usable propellant is depleted, including payload, structure, engines, tanks, and defined residuals.
Yes. Enter the total stage delta-v requirement, including applicable mission losses and allowances.
Not in one calculation. Apply the rocket equation to each stage with its appropriate carried mass and staging assumptions.
The rocket equation is exponential: increasing delta-v increases mass ratio multiplicatively rather than linearly.
Not necessarily. Include residuals in dry mass or reserve according to one consistent mass-accounting convention, without counting them twice.
| Input | Unit | Role |
|---|---|---|
| Dry mass | kg | Mass after usable propellant is depleted. |
| Required delta-v | m/s | Ideal velocity change required from this stage. |
| Specific impulse | s | Effective vacuum or mission-average Isp. |
| Propellant reserve | % | Extra propellant added after the ideal calculation. |