Fiber Optic Distance Chart — OM1–OM5 & OS2
Maximum standardized reach for every common ethernet application by fiber type. Values are IEEE 802.3 PMD specs except the SWDM rows, which are MSA (labeled in the basis column) — an optic can be sold to run farther, but these are the numbers a design can lean on. A dash means the application is not specified for that fiber.
Reach by application and fiber type
| Application | OM1 | OM2 | OM3 | OM4 | OM5 | OS2 (SM) | Basis |
|---|---|---|---|---|---|---|---|
| 1000BASE-SX (1G, 850 nm) | 275 m | 550 m | 550 m | 550 m | 550 m | — | IEEE 802.3z |
| 1000BASE-LX (1G, 1310 nm) | 550 m* | 550 m* | 550 m* | 550 m* | 550 m* | 5 km | IEEE 802.3z |
| 10GBASE-SR (850 nm) | 33 m | 82 m | 300 m | 400 m | 400 m | — | IEEE 802.3ae |
| 10GBASE-LR (1310 nm) | — | — | — | — | — | 10 km | IEEE 802.3ae |
| 10GBASE-ER (1550 nm) | — | — | — | — | — | 40 km | IEEE 802.3ae |
| 25GBASE-SR (850 nm) | — | — | 70 m | 100 m | 100 m | — | IEEE 802.3by |
| 40GBASE-SR4 (MPO parallel) | — | — | 100 m | 150 m | 150 m | — | IEEE 802.3ba |
| 40GBASE-LR4 (WDM) | — | — | — | — | — | 10 km | IEEE 802.3ba |
| 40G-SWDM4 (duplex LC) | — | — | 240 m | 350 m | 440 m | — | SWDM MSA (not IEEE) |
| 100GBASE-SR4 (MPO parallel) | — | — | 70 m | 100 m | 100 m | — | IEEE 802.3bm |
| 100G-SWDM4 (duplex LC) | — | — | 75 m | 100 m | 150 m | — | SWDM MSA (not IEEE) |
| 100GBASE-LR4 (WDM) | — | — | — | — | — | 10 km | IEEE 802.3ba |
| 400GBASE-SR8 (MPO-16 parallel) | — | — | 70 m | 100 m | 100 m | — | IEEE 802.3cm |
| 400GBASE-DR4 (parallel SM) | — | — | — | — | — | 500 m | IEEE 802.3bs |
| 400GBASE-FR4 (CWDM) | — | — | — | — | — | 2 km | IEEE 802.3cu |
| 400GBASE-LR8 (WDM) | — | — | — | — | — | 10 km | IEEE 802.3bs |
Reading the table for design
Two patterns do most of the work. First: within multimode, each speed generation cut reach roughly in half until OM3/OM4 restored it — which is why OM1/OM2 are effectively dead for anything above 1G. Second: single-mode reach is a property of the optics (LR 10 km, ER 40 km), not the fiber, so OS2 never becomes obsolete the way OM1 did. The rule that falls out: inside a room, multimode with cheap VCSEL optics; between rooms or buildings, or wherever there is any distance doubt, pull OS2 — the multimode vs singlemode comparison walks the trade-off, and the transceiver chart decodes the optic names in the application column.
Common questions
How far can OM4 fiber run 10 Gbps?
400 meters — the IEEE 802.3ae engineered value for 10GBASE-SR on OM4 (OM3 runs 300 m). Vendor tables sometimes quote 550 m on OM4; that is an engineered-link claim outside the standard. OM5 adds nothing at 10G — its 850 nm bandwidth matches OM4; the OM5 advantage only appears with SWDM optics.
What is the maximum distance for single-mode fiber?
It depends on the optics, not the glass: 10 km with LR transceivers, 40 km with ER, 80 km with ZR (a vendor convention), and effectively unlimited with amplified DWDM systems. For premises and campus work the practical answer is that OS2 with LR optics covers anything under 10 km — the fiber will never be the limit.
Is OM5 worth it over OM4?
Only if SWDM optics are in the plan. At every single-wavelength 850 nm application (10/25/40/100G-SR), OM5 specifies the same reach as OM4. Its wideband advantage appears with 40G/100G-SWDM4 duplex optics: 440 m vs 350 m at 40G, and 150 m vs 100 m at 100G. For a new plant expecting parallel-optics (SR4-style) growth, OM4 plus more fibers usually beats OM5.
Can 1000BASE-LX run on multimode?
Yes, to 550 m — but only with a mode-conditioning patch cord at each end, which offsets the laser launch to avoid exciting the fiber's center defect. It is a legacy bridge worth knowing when a 1310 nm optic must ride an old OM1/OM2 plant.
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