Want to see your landline telephone power consumption? Enter your wattage, how many hours a day you run it and what you pay per kWh as your electricity rate, then hit Calculate to get the monthly cost and kWh used on your bill. Those same results also cover landline telephone electricity consumption.
Wondering what your landline telephone electricity consumption adds to the monthly bill? A typical cordless phone base sits plugged in around the clock, so even a tiny draw adds up over 24 hours a day, and this guide shows you how to turn watts into kilowatt-hours and dollars in a few seconds. You will also see why a simple corded home phone costs almost nothing to run, how power outages change the picture, and which habits trim your energy use at no cost.
Most people assume a phone is a negligible load, and that is mostly true. Still, a household with a cordless base, a couple of charging handsets and an answering machine keeps several small transformers warm all year. The power consumption of each piece is low, but it never switches off. That is why the telephone energy calculator approach below multiplies a small wattage by a very large number of hours, rather than treating the phone as free. A traditional landline set, the kind that hangs from the phone line alone, is the exception, and the landline phone versus landlines in general question comes up again further down. For comparison, see how much electricity does a projector use.
A traditional corded phone takes the small direct current it needs straight from the telephone line, so it has no plug-in power supply and adds nothing you pay for on your electricity bill. A cordless phone is different: the base plugs into the wall and keeps the handset recharging and listening for calls. Published product criteria put a cordless base at roughly two watts, with each additional handset adding a few tenths of a watt, so your own telephone wattage will usually sit between about 2 and 4 watts. Check the label under the base or the user manual for the exact wattage of your telephone, and look for an Energy Star rated model if you are shopping.
The calculator needs only three inputs, and each one maps to something you can look up in a minute:
The math behind any energy usage calculator is the same chain of three steps: convert watts to kilowatts, multiply by hours to get kilowatt hour figures, then multiply by your price. Written out, the daily energy is:
$$\text{kWh per day} = \frac{\text{Watts} \times \text{Hours used per day}}{1000}$$
and the money follows from it:
$$\text{Cost} = \text{kWh} \times \text{Rate per kWh}$$
Multiply the daily kWh by 30 for a month or by 365 for a year, then apply the same price to each. The result gives the cost per day, cost per month and cost per year that any telephone energy usage calculator displays. Because the rate is a straight multiplier, doubling either the wattage or the price doubles the answer, which makes sensitivity checks easy to do by hand.
Suppose your cordless base is rated at 2.6 W and two extra handset cradles add 0.3 W each, so the setup draws 3.2 W in total. It stays plugged in for 24 hours, and your utility charges $0.17 per kWh.
$$\text{kWh per day} = \frac{3.2 \times 24}{1000} = 0.0768 \text{ kWh}$$
That is 2.304 kWh per month (30 days) and 28.032 kWh per year, which costs $0.01 per day, $0.39 per month and $4.77 per year. The energy consumption of a cordless phone setup like this is real but modest.
| Electricity rate (per kWh) | Yearly kWh | Yearly cost |
|---|---|---|
| $0.12 | 28.032 | $3.36 |
| $0.17 | 28.032 | $4.77 |
| $0.28 | 28.032 | $7.85 |
The table keeps the 3.2 W load fixed and changes only the electricity rate, so you can see how much your local price matters compared with the phone itself. Even at the high end the whole telephone costs less than a single cup of coffee per year.
Energy cost is only half of the story people search for. The other half is whether landline phones keep working when the lights go out, which is why power outages matter here, and the honest answer depends on the kind of handset and network behind it. During a power outage a corded unit on a copper circuit usually keeps ringing, while many cordless models go silent at once.
The phone company powers the line from its own exchange, pushing a low direct current through copper wire pairs and copper wires to your handset. The microphone turns your voice into varying current, a small electromagnetic coil drives the earpiece, the ringer responds to a ringing signal, and the dial sends pulses or tones back. None of that needs your wall outlet, which is why traditional landlines earned a reputation for dependable service in emergencies. Even landlines from decades ago work this way, and a landline phone on that circuit survives most power outages. Those analog signals travel over wired circuits that the carrier keeps alive with its own battery banks.
A cordless base needs mains power to run its radio, so power outages take the whole system offline unless it has battery backup. A small standby battery can bridge a short blackout, and keeping one corded set in a drawer is the cheapest insurance. Be aware that VoIP and internet-based home service rely on a modem and router on your home internet connection, so they fail during outage events unless those devices have their own power supply, while cellular-based wireless bases with a built-in battery keep going.
Regulators including the FCC have allowed carriers to retire older copper infrastructure in many areas, replacing it with fibre or fixed-wireless service. If your provider moves you to a new network, your landline may quietly start depending on household electricity. Ask the carrier whether a backup battery is included, because that single change decides how reliable the line is during blackouts and every other emergency.
Marguerite Oyelaran is deciding whether to retire the cordless set in her hallway. The label under the base reads 2.9 W, and the two extra handset cradles in the kitchen and the guest room are each marked 0.4 W, so she enters 3.7 W as the power use. The base never leaves its outlet, so hours used per day stays at 24, and her latest statement lists $0.214 per kWh. For comparison, see how many watts does a landscape lighting use.
The telephone energy usage calculator returns 0.0888 kWh per day and 32.412 kWh per year, which is $6.94 annually. That is the electricity usage of a cordless phone she can now name in dollars, not a guess.
She then reruns it with 2.0 W, the figure in the ENERGY STAR telephone criteria for a cordless unit: 17.52 kWh and $3.75 per year. A new base would save $3.19 a year, which will not repay a purchase of any size, so she keeps the old one.
The one change worth making is the guest-room cradle, which is rarely used. Unplugging it removes 0.4 W, or 3.504 kWh, which is about $0.75 per year, and she moves it to a drawer next to the corded phone she keeps for outages.
Mobile phones draw more energy overall than landline phones or other landlines, largely because of the radio networks behind them rather than the handsets alone. Researchers who looked at the whole system found that a cell phone and its infrastructure used several times the power of a wired set per subscriber. The comparison below keeps to qualitative points where figures vary by model. Related: how much electricity does a joystick use.
| Feature | Corded phone | Cordless phone | Mobile phones |
|---|---|---|---|
| Wall power needed | No | Yes, for the base | Yes, for the charger |
| Signal type | Analog signals over copper | Radio link to a base | Cellular radio |
| During an outage | Usually works | Needs battery backup | Works until the battery drains |
For a typical home, the extra reliability of a corded set, which is simply more reliable in a storm, is worth far more than the few dollars it saves, and the power it draws is effectively zero.
There is not much to cut, but the energy efficiency habits below cost nothing and apply to every small plug-in device in the house:
An Energy Star mark tells you the product meets a published standby limit, and the same logic applies to any plug-in gadget. On a cordless phone, compare the label wattage against your current base, then re-run the numbers through the calculator to see whether the saving justifies buying anything new. Usually it does not, so wait until the old one fails.
A few details keep your estimate honest. Use the average wattage only when you cannot find a rating, and replace it with the real label value as soon as you can. Enter an exact price from your bill rather than a national average, since regional rates vary widely. If the handset is in active usage for an hour a day, the extra draw is tiny, so most of the usage figure comes from standby time. Round only at the end, because early rounding of the rate skews the yearly cost. Finally, remember that the best energy figure is the one you measure: a plug-in watt meter on the base for a day settles any doubt about energy usage.
If you want to lower your electricity spending, the phone is a poor target. The modem, the router, the answering machine and the cordless charger together may draw more than the telephone itself, so treat them as one group when you measure. Most landline phones and landlines still share that same small standby profile, and power outages are the only time it changes.