To convert rods to astronomical units, multiply by 3.361812556e-11. That factor is the whole relationship: both units measure length, so the conversion is a proportion with no offset and no substance-specific constant.
Sixteen and a half feet, or a quarter of a chain; it survives in old deeds and fence estimating. Exactly 149,597,870,700 metres — the Earth–Sun distance, and the natural ruler for the solar system.
The mil and the millimetre are not the same thing and are out by a factor of about forty. A mil is one thousandth of an inch — 0.0254 mm — and a spec sheet that quotes film thickness in mils means the small unit. British drawings write the same size as "thou". The tables underneath give both a plain step-by-step lookup and a list of real quantities expressed in astronomical units, so you can sanity-check whether your answer is a plausible size.
The formula
rods- The amount you are converting, in rods
3.36181255553e-11- The exact number of astronomical units in one rod
astronomical units- The converted result
How it works, step by step
- Enter the value in rods.
- It is multiplied by 3.36181255553e-11, the exact factor between the two units.
- The answer is shown in astronomical units, with the reverse conversion beneath it.
- Check the reference table if you want a figure of comparable size.
Worked examples
An Olympic pool: 9.94 rd in astronomical units
Take an olympic pool, roughly 9.94 rd. The conversion is a single multiplication — 9.94 × 3.36181e-11 — giving 3.34164e-10 AU. Because the relationship is proportional, doubling the input doubles the answer to 6.68328e-10 AU.
The Eiffel Tower: 65.6 rd in astronomical units
The Eiffel Tower comes to about 65.6 rd. Multiplying by the factor: 65.6 × 3.36181e-11 = 2.20535e-09 AU. Dividing the answer back by 3.36181e-11 returns the figure you started with, which is the quickest way to check you have the factor the right way up.
How to read your score
Frequently asked questions
How many astronomical units are in one rod?
Exactly 3.36181255553e-11. Every figure on this page is that one number multiplied by your input, so the only rounding is at the display step.
What is the formula to convert rods to astronomical units?
astronomical units = rods × 3.36181255553e-11. Reversed, rods = astronomical units ÷ 3.36181255553e-11, which is the same as multiplying by 29,745,858,327.4.
Which is the bigger unit, the rod or the astronomical unit?
The astronomical unit. One rod is only 3.36181e-11 of a astronomical unit, so it takes 2.97459e+10 rods to make one astronomical unit.
What does this quantity actually measure?
Both units measure length. That is why a single factor is enough: there is no temperature offset and no material property involved, unlike conversions that cross between different quantities.
What is a rod?
Sixteen and a half feet, or a quarter of a chain; it survives in old deeds and fence estimating.
What is a astronomical unit?
Exactly 149,597,870,700 metres — the Earth–Sun distance, and the natural ruler for the solar system.
Why does my answer differ from another converter?
Almost always because the other tool rounded the factor before multiplying. This page keeps full double precision through the calculation and rounds only for display, and it prints the factor it used so you can see where any difference came from.
Rods to astronomical units reference tables
| Rods | Astronomical Units |
|---|---|
| 0.5 rd | 1.68091e-11 AU |
| 1 rd | 3.36181e-11 AU |
| 2 rd | 6.72363e-11 AU |
| 3 rd | 1.00854e-10 AU |
| 5 rd | 1.68091e-10 AU |
| 10 rd | 3.36181e-10 AU |
| 20 rd | 6.72363e-10 AU |
| 25 rd | 8.40453e-10 AU |
| 50 rd | 1.68091e-09 AU |
| 75 rd | 2.52136e-09 AU |
| 100 rd | 3.36181e-09 AU |
| 250 rd | 8.40453e-09 AU |
| 500 rd | 1.68091e-08 AU |
| 1000 rd | 3.36181e-08 AU |
| 5000 rd | 1.68091e-07 AU |
Exact factor: 1 rod = 3.36181255553e-11 astronomical units.
| Quantity | rd | AU |
|---|---|---|
| A credit card’s long edge | 0.01702 rd | 5.722e-13 AU |
| A door height | 0.404 rd | 1.358e-11 AU |
| An Olympic pool | 9.942 rd | 3.342e-10 AU |
| The Eiffel Tower | 65.62 rd | 2.206e-09 AU |
| A marathon | 8390 rd | 2.821e-07 AU |
| Earth’s diameter | 2.534e+06 rd | 8.518e-05 AU |
Published reference values, converted with the same factor this page uses.