Newtons to dynes: one force in two measurement systems
What this conversion does
The dyne is the CGS unit of force: the push required to accelerate one gram at one centimetre per second squared. Nothing in that definition is exotic, and the numbers it yields are often easier to read than the SI ones — the surface tension of water is 72 dynes per centimetre, a quantity nobody wants to quote as 0.072 newtons per metre without reaching for a calculator. Multiplying a newton value by 100000 moves it onto that scale exactly, with no rounding step at all.
How CGS relates to the system in use today
CGS stands for centimetre, gram, second, and it was the working system in physics laboratories for most of the nineteenth century. Its unit of force is the dyne, and the bridge to the newton is a pure power of ten because only prefixes changed: the metre is a hundred centimetres and the kilogram is a thousand grams, so the force unit comes out a hundred thousand times smaller. No arbitrary metal cylinder is involved, which is precisely why the factor is so clean.
Newton to dyne conversion table
Small forces, where the dyne is the natural size. Surface tension, electrophoresis and single-molecule work all live in this range, and the newton column is mostly a run of decimal places.
| Newton (N) | Dyne (dyn) |
|---|---|
| 1 | 100000 |
| 10 | 1000000 |
| 100 | 10000000 |
| 500 | 50000000 |
| 1000 | 100000000 |
| 9806.65 | 980665000 |
| 10000 | 1000000000 |
Why the factor is a round hundred thousand
A newton accelerates a kilogram by a metre per second squared. Rewrite the kilogram as a thousand grams and the metre as a hundred centimetres, and that same expression becomes a hundred thousand gram-centimetres per second squared, which is a hundred thousand dynes. The clean factor is not a coincidence or a convention; it falls straight out of the two prefix changes, and that is why it can be written with five zeroes instead of a long decimal.
Where the dyne still earns its place
Two fields never gave it up. Surface tension is quoted in dynes per centimetre because the numbers land between 20 and 80, a range a person can hold in their head. Electrophoresis and optical tweezer work use dynes and piconewtons for much the same reason: the forces involved sit far below one newton, and a unit that turns them into small integers beats one that turns them into long decimals.
Frequently asked questions
What is a dyne in terms of newtons?
One dyne is 0.00001 newtons, or ten micronewtons. Going the other way, a single newton is 100000 dynes. The relation is exact in both directions, with no repeating decimal and no approximation, which is unusual among the force units on this site.
Why is there a separate CGS system at all?
Because nineteenth-century physics was done at bench scale, where grams and centimetres are the natural sizes. CGS produced a coherent set of electrical and magnetic units that many physicists found handier than the metre-kilogram-second alternatives, and some of its units, the dyne and the erg among them, are still in print.
Where would I actually meet a dyne?
In a surface tension table, in an electrophoresis protocol, or in an older paper on colloid chemistry. A water meniscus pulls with about 72 dynes for every centimetre of contact line, and a soap film pulls with roughly a third of that. Blood viscosity measured in a capillary viscometer is also traditionally reported in dyne units.
Does the conversion lose accuracy at very small forces?
No, and this is the one conversion in the category that cannot lose accuracy at all, because multiplying by a power of ten only moves the decimal point. A force of 0.0000001 newtons becomes 0.01 dynes exactly. Nothing is rounded on the way through.
Is the dyne used in engineering as well as physics?
Rarely. Structural and mechanical work left the CGS system behind long ago, and a load expressed in dynes would be an unwieldy number for anything a person can see. Engineering settled on newtons and their multiples, while the dyne stayed where it started, on the laboratory bench and in the scientific paper.