The fundamental difference
A fixed router is mains-powered, stays in one place and is built to serve a building. A MiFi is battery-powered, fits in a pocket and is built to serve you and a handful of devices wherever you happen to be. Everything else follows from that one distinction.
Because a fixed router does not have to worry about battery life, it can run its radios at full power continuously, include multiple Ethernet ports, drive external antennas and keep dozens of clients connected. A MiFi must budget every milliwatt against runtime, so its Wi-Fi radio is deliberately modest and its antennas are internal.
This means the comparison is rarely about which device is better. It is about whether you need coverage and capacity in a fixed location, or connectivity that travels.
Coverage and device count
A typical MiFi is specified for a small group of devices and a coverage radius that suits a room, a car or a hotel desk. Push it beyond that and performance falls away quickly, not because the mobile connection is saturated but because the Wi-Fi radio and processor are small.
A fixed router with dual-band Wi-Fi comfortably handles a household of phones, laptops, smart televisions and cameras, and gives you wired ports for the devices that should never be on Wi-Fi in the first place — desktop computers, network video recorders and printers.
If your device count is heading past about ten, or your building is larger than a compact flat, the fixed router is the only sensible answer, and you may also want mesh nodes to extend it.
- One or two people, moving between locations — MiFi.
- A household or an office in one building — fixed router.
- Need Ethernet ports for a desktop, printer or NVR — fixed router.
- Need an external antenna to fix a weak signal — fixed router (check it has antenna connectors).
- Need a cheap emergency backup line — MiFi with a second-network SIM.
The antenna question
This is the point that decides many purchases. Most fixed 4G and 5G routers include external antenna connectors, which means a weak signal can be fixed later with an outdoor antenna rather than a new device. Very few MiFi units offer this, and those that do usually need a fiddly adapter for a tiny connector.
If you are in an area where signal is marginal — and that describes a great many addresses once you leave the metro centres — buying a device without antenna connectors closes off your cheapest future upgrade path.
Check the specification for the connector type as well as the port count. SMA, TS9 and CRC9 are all common and are not interchangeable without an adapter.
Technician’s tip
If you are undecided and your signal is anything less than strong, buy the fixed router with antenna ports. It is the option that leaves you somewhere to go if conditions turn out worse than expected.
Power, outages and cost of ownership
A MiFi has its own battery, so it keeps working during a power cut with no additional equipment. That is a real advantage and is why many households keep one charged as a backup even when they have a fixed router as the main connection.
A fixed router needs mains power, but a small DC UPS sized for router loads keeps it running for hours at a very modest cost. Routers draw very little power, so you do not need a large inverter to keep the internet alive through an outage.
On running costs, both consume the same mobile data, so the difference is entirely in hardware. The common and sensible pattern is a fixed router as the primary connection and an inexpensive MiFi on a different network as the fallback.