Maintenance procedure · Written to ASD-STE100 Issue 9 · Formatted to ANSI Z535

How to Identify an Ethernet Cable's Category

Read the print on a Cat5e, Cat6 or Cat6A cable and check whether the cable is the reason your connection is slow.
ApplicabilityTwisted-pair Ethernet patch cables with printed text on the jacket, of the kind used to wire a home or small-office network. Fiber-optic cable and bulk cable with no printed legend are not covered here.
Task time4 min to 4 min editorial estimate, not a measurement
PersonnelOne
Revisionv1 · 2026-08-04
BEFORE YOU BEGIN

Before you begin. This procedure is general reference information, not professional advice. Equipment varies by manufacturer, model, and year. Always follow the documentation supplied with your equipment — where it differs from this page, follow the manufacturer. Verify that you have the tools, the working conditions, and the ability to do this task safely. If anything is unclear, if the equipment is damaged, or if the task exceeds your experience, stop and use a qualified professional. You are responsible for your own safety and for the outcome. This site accepts no liability for any loss, damage, or injury arising from the use of this information.

Specifications marked unverified could not be traced to a manufacturer source. Do not rely on them — obtain the value from your equipment documentation.

Summary

Every Ethernet patch cable has its category printed along the length of the jacket, usually as CAT5E, CAT6 or CAT6A. This page shows you where to find that print and how to read it, so you can settle the cat5e vs cat6 question for the cable already in your hand, instead of guessing from its color or its price. It also shows you how to check the link speed your equipment is actually using, so you can compare what the cable is rated for against what your network needs. This page will not print an exact top speed or maximum length for every category: those figures sit inside a paywalled standard, ANSI/TIA-568, and a number this page cannot trace to a source it read is a number it will not guess. Where a figure is traced to the cable industry's own documentation, the page says so and names the source. If you are asking whether your ethernet cable is slowing you down, the more common answer in a home is that the router, the Wi-Fi, or the internet plan is the limit, not the cable in the wall — this page helps you rule the cable in or out.

Safety

NOTICE

DO NOT USE CABLE COLOR TO IDENTIFY THE CATEGORY.
Color is not part of the category standard, and it changes between manufacturers.

NOTICE

DO NOT CUT THE CABLE JACKET OR REMOVE THE CONNECTOR TO EXAMINE THE INTERNAL WIRES.
This action can damage the cable beyond use.

Necessary equipment

ItemNote
The Ethernet cable you want to identifyUse a cable with readable print on the jacket.
Bright light or flashlight optionalUse this light to read small or faint print.
Magnifying glass optionalUse this glass to read small or worn print.
Pen and paperRecord the category code before you compare it.

Find the category on the cable

Estimated 2 min

  1. Find the cable you want to identify.
    <1mReport a problem with step 1, Find the category on the cable
  2. Find the printed text along the length of the cable jacket.
    <1mReport a problem with step 2, Find the category on the cable
  3. Read the text for the letters CAT or the word CATEGORY.
    <1mReport a problem with step 3, Find the category on the cable
  4. Record the number and letter that follow the letters CAT.
    • Common codes are 5E, 6 and 6A.
    <1mReport a problem with step 4, Find the category on the cable
  5. If the first side of the cable has no print, examine the other side.
    <1mReport a problem with step 5, Find the category on the cable
  6. Use a bright light or a magnifying glass if the print is small.
    <1mReport a problem with step 6, Find the category on the cable

Compare the category to your connection

Estimated 1 min to 2 min

  1. Open the network settings on your computer, or open your router administration page.
    <1mReport a problem with step 1, Compare the category to your connection
  2. Find the link speed shown for the Ethernet connection.
    • The network settings show the link speed in Mbps or Gbps, for example 1 Gbps.
    <1mReport a problem with step 2, Compare the category to your connection
  3. Compare the link speed to the category you recorded.
    <1mReport a problem with step 3, Compare the category to your connection

Decide if the cable is the limit

Estimated under a minute

Category 6A cable maximum supported network speed
Manufacturer or standard verified
10 Gbps

Source: Category 6A Cables · tier 1 · accessed 2026-08-04

Category 6A cable maximum channel length rated for 10 Gigabit Ethernet
Manufacturer or standard verified
100 m

Source: Category 6A Cables · tier 1 · accessed 2026-08-04

Category 5e cable maximum supported network speed
Unverified — do not rely on this value
CONSULT THE CABLE MANUFACTURER OR ANSI/TIA-568

No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.

Category 6 cable maximum supported network speed
Unverified — do not rely on this value
CONSULT THE CABLE MANUFACTURER OR ANSI/TIA-568

No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.

  1. Consult the cable manufacturer for the rated speed of a Category 5E or a Category 6 cable.
    • The TIA-568 standard also gives the rated speed for each category.
    <1mReport a problem with step 1, Decide if the cable is the limit
  2. Remember that Category 6A is the exception on this page.
    • It alone reaches a speed of 10 Gigabit Ethernet, over a run of 100 meters.
    <1mReport a problem with step 2, Decide if the cable is the limit
  3. Replace the cable if the category is below what your equipment and your plan both need.
    <1mReport a problem with step 3, Decide if the cable is the limit
  4. Keep the cable if the link speed already matches your plan speed.
    <1mReport a problem with step 4, Decide if the cable is the limit

Terminology

This page uses one term for each item and holds it throughout, as ASD-STE100 requires. Equipment sellers and other guides use the names below for the same parts.

Cable category
Also called: cat rating, ethernet cable speed, cable says cat5, what kind of ethernet cable, cat5e vs cat6 vs cat6a
Category 5e (Cat5e)
Also called: cat 5e, cat5e cable, regular ethernet cable
Category 6 (Cat6)
Also called: cat 6, cat6 cable, gigabit ethernet cable
Category 6A (Cat6A)
Also called: cat 6a, cat6a cable, augmented category 6, 10 gig ethernet cable
Link speed
Also called: connection speed, network speed, negotiated speed

When to use a professional

Consult the cable manufacturer for the exact rated speed of a Category 5E or a Category 6 cable. Consult a network technician if the connection stays slow after you find the cable category is sufficient.

Common questions

What Ethernet cable do I need for gigabit internet?

Check the print on the cable you already have before you buy a new one — many already-installed Cat5e and Cat6 cables will carry a gigabit connection. This page shows you how to read that print and how to check the link speed your equipment reports. For the exact speed your particular cable supports, consult the cable manufacturer's documentation, because that figure depends on the cable's construction and length, not only its printed category.

Cat5e vs Cat6 vs Cat6A: what is the difference?

The number and letter after CAT is the cable's category, and a higher category is built to a tighter specification for signal quality. Category 6A is the only category on this page with a maximum speed traced to a source this page read: it supports 10 Gigabit Ethernet over a full 100-meter run, according to the cable manufacturer CommScope. For Category 5e and Category 6, consult the cable manufacturer or the ANSI/TIA-568 standard for the exact rated speed.

My cable says CAT5 without the E. Is that the same as Cat5e?

No. CAT5 is an earlier category than CAT5E. CAT5E replaced CAT5 with a tighter specification for crosstalk between the wire pairs. Treat a cable printed only CAT5, with no E, as the oldest cable on your network, and check its link speed if your connection is slow.

Does a higher category always mean a faster connection?

No. Your connection speed is also limited by your router, your modem, your network card and your internet plan. A Category 6A cable connected to older gigabit equipment still runs at gigabit speed, not 10 gigabit. Check the slowest part of the chain, not only the cable.

Is my Ethernet cable slowing me down?

Rarely, in a typical home. Compare the link speed shown in your network settings, from the steps on this page, to your internet plan speed. If the link speed already matches your plan, the cable is not the bottleneck, whatever its category.

Sources

Every specification on this page is traced to one of these sources. Tier 1 is a manufacturer document, a published standard, or a government safety authority. See Standards for the full tiering rule.

  1. Tier 1Category 6A CablesCommScope, Inc. · accessed 2026-08-04 · re-verification due 2027-01-31
  2. Tier 1Twisted Pair CablesCommScope, Inc. · accessed 2026-08-04 · re-verification due 2027-01-31

Revision history

Current version 1 · updated 2026-08-04 · next review due 2027-08-04

  1. v1 · 2026-08-04First draft. The only numeric performance specification this session could trace to a source it read is Category 6A's: CommScope's own Category 6A Cables product page, fetched live this session, states plainly that Cat 6A supports 10 Gigabit Ethernet channels up to 100 meters. CommScope's Category 6 and Category 5e product pages were fetched too and carry no comparable performance sentence, and the ANSI/TIA-568 standard that would give a general figure for every category is paywalled and was not read (brief rule 10 / independent creation). Rather than publish a remembered number for Category 5e or Category 6, both are routed to the cable manufacturer or ANSI/TIA-568 (brief rule 1). The page teaches the two things that are directly checkable without a paid standard: how to read the printed category off the cable jacket, and how to compare that category against the link speed the reader's own equipment reports, which is how a reader actually finds out whether the cable is the bottleneck. No hazard on this page concerns personal injury; both hazards are NOTICE-level and warn against using cable color as a substitute for the printed category and against cutting the cable open, neither of which is safety-critical.

Corrections to this page are listed in the public corrections log. Reports that are credible and not yet verified are listed in the public errata register, and an open one renders above the step it concerns.

Comments and corrections

Found an error? A correction with a manufacturer source is applied and logged publicly. You can also write to corrections@fixchecklist.com.

Every step above carries its own report control, which tags the report with that step so a correction reaches the right place. For anything about the procedure as a whole — the order of the sections, a step that is missing, something that did not match your equipment — use this: report something about this whole procedure.

The comment system is not connected yet. Comments are stored in GitHub Discussions through Giscus, outside this site, so that a redeploy cannot destroy them.