Model planets as spheres, spheroids, or ellipsoids. Switch units and track precision with ease today. Export tables to CSV or PDF for reports anytime.
Use semi-axes (a, b, c) as radii from the center, not full diameters.
These examples use common reference values (approximate) and the oblate spheroid model where relevant.
| Body | Model | Inputs (km) | Volume (km^3) | Earth Volumes |
|---|---|---|---|---|
| Earth | Oblate spheroid | a=6378.137, c=6356.752 | ≈ 1.08321e12 | 1.000 |
| Mars | Sphere | r=3389.5 | ≈ 1.6318e11 | ≈ 0.151 |
| Jupiter | Oblate spheroid | a=71492, c=66854 | ≈ 1.4313e15 | ≈ 1321 |
For high-precision work, use updated radii and consistent reference frames.
Planetary volume sets the scale for average density, pressure, and bulk composition when paired with mass. Because volume scales with the cube of size, small radius updates can shift volume noticeably. This calculator reports m^3 and km^3, plus an Earth-volume ratio for immediate perspective.
Most worlds are not perfect spheres. Rotation and tides create flattening, so an oblate spheroid can outperform a mean-radius sphere for many planets. For asymmetric targets, a triaxial ellipsoid approximates three principal semi-axes. A better model reduces systematic error before any advanced mapping.
The spherical option uses V = (4/3)πr^3 and is ideal for first-pass work and many small moons. If you only know diameter, enter half as r. Keep units consistent; the calculator converts the selected length unit internally before computing.
For rotating planets, equatorial radius a exceeds polar radius c. The spheroid volume V = (4/3)πa^2c captures flattening directly and is widely used in geodesy and planetary datasets. Earth has a≈6378 km and c≈6357 km, giving about 1.08321×10^12 km^3. Gas giants show even larger equator-to-pole contrasts.
When dimensions differ along three directions, V = (4/3)πabc provides a compact approximation used for irregular moons and many asteroids. Enter a, b, and c as semi-axes (center-to-surface), not full lengths. The equivalent-radius output converts that volume into an intuitive spherical radius.
If you supply mass, the calculator returns average density ρ = m/V in kg/m^3. This helps distinguish rock, ice, and gas-rich bodies and can flag inconsistent inputs quickly. Remember it is a bulk mean value; layered interiors can share the same average density. Prefer mass and radii from the same reference source.
The optional uncertainty field applies a simple percentage to the final volume for reporting ranges. As a rule of thumb, a 1% radius uncertainty produces roughly 3% spherical volume uncertainty. For spheroids and ellipsoids, sensitivity distributes across the axes and their measurement quality.
CSV export supports spreadsheets and automated pipelines, while PDF provides a compact record for lab notes and technical memos. Always report the selected model and input radii/axes, because conventions differ between mean, equatorial, and volumetric radii. The Earth-volume ratio helps compare bodies quickly across very different size scales.
Use mean radius for quick spherical estimates. Use equatorial and polar radii for rotating planets where flattening matters. The spheroid model usually improves accuracy for Earth, Jupiter, and Saturn.
They are semi-axes: center-to-surface distances along three principal directions. Do not enter full diameters. If you have full axis lengths, divide each by two before input.
SI work often requires m^3, while planetary science commonly uses km^3 for readability. The values are consistent because 1 km^3 equals 10^9 m^3.
It divides your computed volume in km^3 by an approximate Earth reference volume of 1.08321×10^12 km^3. This produces a dimensionless ratio useful for comparisons.
Yes. Provide mass and the calculator computes ρ = m/V in kg/m^3. This is an average bulk density, not a surface or core density, and it depends on input quality.
It is the radius of a sphere having the same computed volume. It helps compare different models using one intuitive size parameter, even if the original shape is spheroidal or ellipsoidal.
Enter a percentage to display a simple +/- volume range. It is a reporting aid, not a full error propagation. For rigorous uncertainty, propagate axis uncertainties through the chosen volume formula.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.