Optical fiber

Fiber Reach by Type

Pick the fiber type (OM1–OM5 multimode, OS1/OS2 singlemode) and the speed and I show the maximum distance supported by IEEE 802.3, with the limiting factor (attenuation or modal bandwidth).

redzilla.cl — fiber

Max distance

—

IEEE standard

—

802.3

Limiting factor

—

Distance —

Standard —

Distances from the IEEE 802.3 standard (worst case, full channel). Better transceivers or runs with fewer connectors/splices can reach farther; always validate with a loss budget.

The same fiber at each speed

Speed	Distance	Standard

Reference table · IEEE reach (m)

Fiber	1G	10G	25G	40G	100G

MMF = multimode (850 nm) · SMF = singlemode (LR/LX). — = not a standard for that speed.

How to read it · limiting factor and modal bandwidth

1. On multimode (OM1–OM5) the 850 nm laser enters through many modes that arrive out of step (modal dispersion). The limit is set by modal bandwidth (MHz·km): more BW, more distance. That is why OM3 (2000 MHz·km) reaches farther than OM2 (500) at 10G.

2. On singlemode (OS1/OS2) there is a single mode: no modal dispersion. The limit is the link attenuation (loss budget). That is why the LR/LX/LR4 standards reach 10 km (and more with ER/ZR variants).

3. OM5 shares reach with OM4 on a single 850 nm channel; its advantage is SWDM4 (several wavelengths per fiber), outside the scope of this table.

4. Combinations marked — are not standard (e.g. OM1/OM2 at 25/40/100G): use OM3/OM4 or singlemode.

Runs locally in your browser · no sign-up · nothing leaves your browser

How it works

The tool matches the fiber type (OM1, OM2, OM3, OM4 and OM5 multimode; OS1/OS2 single-mode) with the link speed (1G, 10G, 25G, 40G or 100G) and returns the maximum distance defined by the IEEE 802.3 standard for that combination: for example 10GBASE-SR over OM4 reaches 400 m and 10GBASE-LR over single-mode reaches 10 km. If the combination does not exist as a standard (OM1 at 25G, for instance), it says so and suggests moving up to OM3/OM4 or to single-mode fiber.

It also shows the limiting factor. In multimode fiber the 850 nm laser travels through several modes that arrive out of step, so the limit is set by the modal bandwidth (from 200 MHz·km on OM1 to 4700 MHz·km on OM4/OM5). In single-mode fiber there is only one mode and the limit becomes the link attenuation, which is why LR/LX standards reach 10 km. Values are worst-case per the standard: a channel with few connectors may go somewhat farther, but you should validate it with a loss budget.

Example: how far does 10G go over OM3 and over OM4?

Select OM3 and the 10G speed: the applicable standard is 10GBASE-SR and the IEEE reach is 300 m.
Switch to OM4 keeping 10G: with 4700 MHz·km of modal bandwidth the reach rises to 400 m.
If the run exceeds those values, the table shows the way out: OS1/OS2 with 10GBASE-LR reaches 10,000 m (10 km).

Frequently asked questions

How many meters does OM4 fiber support at 10G, 40G and 100G?

Per IEEE 802.3, OM4 supports 400 m at 10G (10GBASE-SR), 150 m at 40G (40GBASE-SR4) and 100 m at 100G (100GBASE-SR4). These are worst-case standard values; in practice they also depend on the connector and splice loss of the link.

What happens if I use OM1 or OM2 at 25G or 40G?

There is no IEEE standard defined for those combinations: the modal bandwidth of OM1 (200 MHz·km) and OM2 (500 MHz·km) is too low. Even if the link comes up, the error rate is not guaranteed. For 25G and above you need OM3, OM4 or single-mode fiber.

What is the difference between multimode and single-mode fiber in terms of reach?

In multimode fiber (50 or 62.5 µm core) light travels through several modes that disperse, so reach stays between 33 and 550 m depending on fiber and speed. In single-mode fiber (9 µm core) there is a single mode, no modal dispersion, and LR/LX standards reach 10 km; the limit becomes link attenuation.

Does OM5 reach farther than OM4?

On a single 850 nm channel it does not: OM5 shares reach with OM4 (400 m at 10G, 100 m at 25G). Its advantage shows up with SWDM4, which transmits several wavelengths over the same fiber to reduce the number of strands at 40G/100G, not to increase distance.

Was this tool useful?

Disclaimer

We take great care to keep every tool accurate and review it thoroughly; even so, we can't guarantee it is free of errors or take responsibility for how the results are used. We recommend double-checking anything critical.

Found an error? Let us know →