If a cable delivers your full plan and Wi-Fi delivers a fraction of it, your ISP is fine. The fault is inside the house, and there are only four candidates.
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If an Ethernet cable delivers your full plan and Wi-Fi does not, the internet is not your problem and neither is your modem. Four things cause this, and they are easy to separate: you are on the wrong band, the channel is congested, the router cannot go faster, or you are too far away. Work through them in that order — the first two are free.
First, confirm the gap
Test on a cable plugged into the router, then test on Wi-Fi standing next to the router, then test on Wi-Fi in the room where it feels slow. Three numbers. If the cable is fast and Wi-Fi beside the router is also fast, your problem is distance and only the third number is low — skip to the last section. If Wi-Fi is slow even standing next to the router, read on in order.
Cause 1: your device is on 2.4 GHz
This is the most common cause and the least suspected. 2.4 GHz travels further, so phones and laptops cling to it, and it is dramatically slower than 5 GHz — a Wi-Fi 6 router typically rates 2.4 GHz at a few hundred megabits against well over a gigabit on 5 GHz. On a gigabit plan a device stuck on 2.4 GHz can read 100 Mbps while the cable next to it reads 940.
Check which band you are actually on in your phone's Wi-Fi details or the router app. If it is 2.4 GHz while you are standing next to the router, the band steering is not working well — moving a few feet, reconnecting, or temporarily pausing the 2.4 GHz radio will confirm the diagnosis in under a minute.
Cause
How to confirm it
Cost to fix
Device on 2.4 GHz
Check the band in your Wi-Fi details next to the router
Free — reconnect, or adjust band steering
Congested channel
Fast in the morning, slow at 9 p.m.; many neighboring networks
Free — change channel
Router cannot go faster
Wi-Fi slow next to the router on 5 GHz, cable fast
A new router
Distance and walls
Fast next to the router, slow only in far rooms
A node, an extender or a wired access point
The four causes, how to confirm each, and what it costs to fix.
Scroll the table sideways to see every column.
Cause 2: the channel is busy
Wi-Fi is a shared medium — only one radio in earshot transmits at a time on a channel, and earshot includes your neighbors. In a dense street or an apartment building the 2.4 GHz band is effectively full and parts of 5 GHz are contested too. The signature is time of day: fine when the street is asleep, poor in the evening.
The fix is free. Move to a quieter 5 GHz channel, or onto 6 GHz if your hardware has it, and stop using 2.4 GHz for anything that matters. Our interference guide covers the channel work, and Wi-Fi slow at night is the same symptom seen from the other end.
This usually backfires
Do not buy a faster plan to fix this
You have already proved the plan is delivering, because the cable test was fast. Upgrading it raises a ceiling you are not touching, and the Wi-Fi bottleneck will be exactly where it was. The same logic applies to a modem — it passed the cable test too. Will a new router be faster separates the cases where hardware helps from the cases where it does not.
Cause 3: the router is the ceiling
If you are on 5 GHz, standing beside the router, on a quiet channel, and still getting a fraction of your plan, the router is the limit. Two common versions of this: the Wi-Fi radios are from an older generation and cannot reach modern speeds, or the router has gigabit ports and you are paying for more than a gigabit.
That second one is worth checking explicitly, because it is invisible — multi-gig ports explained covers where the cap actually sits. If the router is an ISP-supplied gateway, you can usually replace it and stop paying the rental at the same time: replacing your ISP's router has the math, and how often to replace your router covers whether yours is simply past it.
Cause 4: distance and walls
If Wi-Fi is fast beside the router and slow two rooms away, nothing is broken — that is physics. Keenetic publishes what obstacles cost: a 15 cm interior wall takes 15-20 dB at 2.4 GHz, a 30 cm bearing wall takes 20-25 dB and leaves roughly a tenth of the open-space distance, and higher frequencies suffer more, which is why the fast band disappears first in far rooms.
The fix is a radio closer to the problem, not a stronger one. One weak room: an extender with an Ethernet port or a wired access point. Several weak rooms or a whole floor: a mesh system. Either way, measure first — the room-by-room method tells you how many rooms actually fail, which decides which category you are shopping in. And move the router out of the cabinet before you spend anything: router placement is free and frequently enough.
Two other things worth ruling out
One device, not the network. If only the laptop is slow and phones are fine, the fault is that laptop's adapter or driver, not your Wi-Fi.
A VPN or filtering service. Both add overhead and can halve throughput on a device while the cable test beside it looks perfect.
If the slowness also comes with dropouts rather than just low numbers, Wi-Fi keeps dropping is the better page, and why is my Wi-Fi so slow is the general diagnosis if the cable test was not fast after all.
How we picked
We do not run a test lab. Rankings here are built from the manufacturers' published specifications, measurements taken by independent outlets that do have labs, and the structural reasoning on this site about what a given house or job actually needs. Every product was checked as currently sold before it was included. Where a figure appears it is attributed and linked in Sources; where we have no basis for a claim, it is left out. Our methodology sets out exactly what we will and will not assert.
Quick picks
Ranked by our published scoring rubric (fixes band limits, fixes congestion, fixes distance, value). Tap any row to jump to the full write-up, or go straight to the retailer from the right-hand column. How we score.
#
Product
Best for
Score
Price
1
Illustrative
TP-Link Archer BE550Tri-band Wi-Fi 7 with 6 GHz, 320 MHz channels and 2.5 Gbps ports, measured over 3 Gbps on 6 GHz at close range. The fix when the cable is fast and the Wi-Fi next to the router is not.
TP-Link Archer AX55AX3000 with OFDMA, measured at 823.7 Mbps at 15 ft and still usable at 70 ft in TechGearLab's testing. Enough for any plan at or below a gigabit.
TP-Link Deco BE63Tri-band Wi-Fi 7 rated to about 7,600 sq ft as a two-pack with a dedicated 6 GHz backhaul band. The right purchase when distance rather than the router is the cause.
Scroll the table sideways on a narrow screen. Scores are our editorial assessment from published specifications and independent testing by named outlets — not our own lab results. What we do and do not test.
The picks in full
Illustrative
#1 · When the router is the ceiling
TP-Link Archer BE550
TP-Link · Midrange
The most future-proof router for the money: full Wi-Fi 7 with multi-link operation, 320 MHz channels and 4K-QAM, plus 2.5 Gbps ports throughout.
Key specifications
Standard
Wi-Fi 7, tri-band (includes 6 GHz)
Features
Multi-link operation, 320 MHz channels, 4K-QAM
Measured
Over 3 Gbps on 6 GHz at close range in testing
Wired
2.5 Gbps ports; full gigabit-plus over wired in testing
Score 8.9/10
Fixes band limits9.5
Fixes congestion9.0
Fixes distance7.5
Value9.0
What it gets right
+Gets you the genuinely useful Wi-Fi 7 features — multi-link operation and 320 MHz channels — rather than the badge on dual-band hardware
+2.5 Gbps ports mean it will not cap a fiber or multi-gig cable plan
+Independent testing measured over 3 Gbps on the 6 GHz band at close range
+Vertical tower design takes less shelf space than the antenna-covered alternatives
What to watch for
−6 GHz range is short, so the headline number only applies within a room or two
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Common questions
Why is my internet fast but my Wi-Fi slow?+−
Because the fault is inside the house. Four causes account for nearly all of it: your device is connected on the slower 2.4 GHz band, the channel is congested by neighboring networks, the router's own radios or gigabit ports cap you, or you are simply too far away through too many walls. The first two cost nothing to fix.
Why is my phone's Wi-Fi slow when Ethernet is fast?+−
Most often the phone is on 2.4 GHz. That band reaches further so devices cling to it, and it is several times slower than 5 GHz — enough that a phone can read 100 Mbps while a cable in the same room reads over 900. Check the band in your Wi-Fi details while standing next to the router.
Will a new router fix slow Wi-Fi if my internet is fast?+−
Only if the router is the ceiling. Test on 5 GHz standing next to it on a quiet channel: if that is still a fraction of your plan, a new router helps. If it is fast there and slow two rooms away, a new router in the same position covers the same floor and will not help — you need another radio closer to the problem.
Is it normal for Wi-Fi to be slower than Ethernet?+−
Yes. Ethernet is a dedicated path; Wi-Fi is shared airtime with overheads, retries and competition from neighbors. Expect Wi-Fi to come in below your wired figure even in a good setup. What is not normal is a fraction — if Wi-Fi beside the router is well under half the wired result, something on this page applies.
Illustrative
