Are planet sizes and distances at the same scale?

Yes. The selected Earth model diameter determines one factor, applied to every diameter and mean distance. Earth is 12,756 km across in the planetary source, so a 10 mm model Earth gives 1,275.6 real km per model mm.

Are these current planet positions?

No. The model uses rounded mean orbital distances from NASA’s Planetary Fact Sheet, updated 18 March 2025. Diameters are equatorial for planets; the Sun diameter is twice its mean radius in NASA’s Sun Fact Sheet, updated 9 May 2024. The form does not calculate current positions, alignments or an orbital layout.

Are distances measured between the surfaces?

No. Distances are measured from the Sun’s centre to the planet’s centre, not as gaps between their surfaces. The model includes the Sun and eight planets, with no moon or dwarf-planet data.

Solar System Scale Model Calculator

Enter the model Earth diameter in millimetres. One common factor scales body diameters in mm and rounded mean distances from the Sun in metres, so the size and distance scales agree. At a 10 mm Earth diameter, the mean Earth distance from the Sun is about 117.27814 m.

Scale a collection

Solar system model

Choose the model Earth’s diameter in millimetres. The same linear factor scales all body diameters and mean distances from the Sun, so sizes and distances share one scale.

Model Earth diameter in mm

One model mm represents 1275.6 real km.

Body	Diameter (mm)	Mean distance from Sun (m)
Sun	1090.7808	0
Mercury	3.8248667	45.390405
Venus	9.488868	84.822828
Earth	10	117.27814
Mars	5.3245532	178.73942
Jupiter	112.09156	610.30103
Saturn	94.493572	1122.609
Uranus	40.073691	2247.5698
Neptune	38.827219	3539.5108

Planet diameters and rounded mean orbital distances: NASA NSSDCA Planetary Fact Sheet, updated 18 March 2025. The Sun uses twice the 695,700 km mean radius in the Sun Fact Sheet, updated 9 May 2024. Planet diameters are equatorial. This is a classroom scale model with approximate reference values, not current positions or an orbital layout. Distances are from the Sun’s centre, not gaps between surfaces.

Accuracy. Supplied recipe amounts use proportional arithmetic, displayed to eight significant digits. Solar model values are approximate NASA reference measurements scaled by one common linear factor.

Common questions

Are planet sizes and distances at the same scale?: Yes. The selected Earth model diameter determines one factor, applied to every diameter and mean distance. Earth is 12,756 km across in the planetary source, so a 10 mm model Earth gives 1,275.6 real km per model mm.
Are these current planet positions?: No. The model uses rounded mean orbital distances from NASA’s Planetary Fact Sheet, updated 18 March 2025. Diameters are equatorial for planets; the Sun diameter is twice its mean radius in NASA’s Sun Fact Sheet, updated 9 May 2024. The form does not calculate current positions, alignments or an orbital layout.
Are distances measured between the surfaces?: No. Distances are measured from the Sun’s centre to the planet’s centre, not as gaps between their surfaces. The model includes the Sun and eight planets, with no moon or dwarf-planet data.

Supplied recipe amounts use proportional arithmetic, displayed to eight significant digits. Solar model values are approximate NASA reference measurements scaled by one common linear factor.