Planetary Scale Calculator
I struggled to find Eris-inclusive planetary scale calculators on the web, so here is my own. Dwarf planets in general were oddly missing from most calculators I found. This will give you the scaled values of the sun, all eight planets, seven largest moons, and some favorite trans-Neptunian objects.
Instructions
There are two ways to use this calculator. To find basic planet sizes, find something round and measure it in centimeters. Decide what you'd like that object to represent and enter its measurements in the box below. Or if you'd like to make a solar system scale over a certain distance, enter that distance in meters.Results
| Object | Scaled Diameter (cm) | Scaled Distance from Sun (meters) | |
|---|---|---|---|
| Sun | 1091.68 | ||
| Mercury | 3.83 | 454.47 | |
| Venus | 9.5 | 849.23 | Softball (8.9 cm) |
| Earth | 10 | 1174.05 | |
| Moon (Earth) | 2.86 | ||
| Mars | 5.32 | 1788.86 | |
| Ceres | 0.74 | 3246.74 | |
| Jupiter | 108.48 | 6109.03 | |
| Ganymede (Moon of Jupiter) | 4.13 | ||
| Callisto (Moon of Jupiter) | 3.78 | ||
| Europa (Moon of Jupiter) | 2.45 | US Quarter (2.4 cm) | |
| Io (Moon of Jupiter) | 2.86 | ||
| Saturn | 91.4 | 11197.03 | |
| Rings of Saturn | 214.68 | ||
| Titan (Moon of Saturn) | 4.04 | ||
| Uranus | 39.81 | 22531.57 | |
| Neptune | 38.65 | 35302.57 | |
| Triton (Moon of Neptune) | 2.12 | US Nickle (2.1 cm) | |
| Pluto | 1.86 | 46353.63 | US Dime (1.8 cm) |
| Eris | 1.83 | 80128.71 | US Dime (1.8 cm) |
| Haumea (polar) | 1.65 | US Dime (1.8 cm) | |
| Haumea (equator) | 0.84 | ||
| Makemake | 1.12 | 53759.22 | M&M (1.1 cm) |
| Gonggong | 0.97 | 103594.41 | |
| Quaoar | 0.88 | 51012.4 | |
| Sedna | 0.78 | 593313.45 |
Notes, Recommendations, and Fun Facts
- There are over 200 moons in our solar system and many, many trans-Neptunian objects. I did not mean to leave anyone out, so if you'd like to recommend a favorite, email me (spacefem at spacefem dot com)
- Source for the sizes on this page: https://en.wikipedia.org/wiki/List_of_Solar_System_objects_by_size
- You may notice that the distances get to be absolutely nuts, really fast. This is not a calculation error. Many sources agree with me that objects in space are extremely far apart. If you'd like to make a scale model with accurate distances, pick tiny values.
- A city block is about 100 meters.
- Use a 3cm sun, and you will be able to fit all eight planets on the block, including Neptune.
- Use a standard game marble (1.3cm) for the sun, and you can fit our dear Eris on the block
- Of course in both these scenarios, all other planets must shrink to less than 1mm and can't even be represented by the head of a pin
- But set it up anyway.
- Then tell all the kids to go home and think about their lives.
- Eris and Pluto are very close to the same size. Set Eris to at least 5cm if you want to see even 1mm difference between the two.
- Set Eris to .114 cm (barely over a mm) to hold a fun Eris 5K run with your athletic friends! That would be the distance from Eris to the sun. Jupiter will be a whopping 6.7 cm at that scale and the sun is 68cm - not quite to hula hoop size but definitely noticable.
- 1 mile = 1.61 km. I love the metric system best of all but if you want Americans to feel like they're going a "walkable distance", use 4mm for the Earth and then the Sun-Neptune distance is under a mile.
- I've added some of my favorite round objects as an example field - here are their dimensions in centimeters:
- M&M 1.1
- Marble 1.3
- Dime 1.8
- US Penny 1.9
- Nickle 2.1
- Quarter 2.4
- Hockey puck 7.6
- Softball 8.9
- Volleyball 21
- Soccer Ball 22
- Basketball 24.2