Electrical
GFCI outlet installation cost
A GFCI wired through its LOAD terminals protects every outlet after it on the circuit — so ten outlets across a bathroom, kitchen, garage and outdoors are 5 devices, not ten, and about $552 fitted. The two terminals are the whole job: LINE from the panel, LOAD to the rest, and wired backwards it works and protects nothing. And for every house with two-prong outlets and no ground, a GFCI is the legal fix that costs $25 of parts rather than a rewire.
Written and edited by Pablo Ruiz Quintero
Last reviewed 2026-09-23 · Nothing you type leaves your browser
GFCI outlet installation calculator
Count circuits, not outlets
One GFCI at the first outlet on a circuit protects every outlet after it. The number you need is the number of circuits — and that is not the number the shop sells you.
Every receptacle. A bathroom usually sits on one 20 A circuit, so one GFCI at the first outlet does the whole room — and often the second bathroom on the same run.
Every countertop receptacle and anything within six feet of the sink. Code wants two small-appliance circuits here, so it is normally two GFCIs, not one per outlet.
All of them, since the 2020 code — including the ceiling one the door opener plugs into. Usually one circuit.
Every outdoor receptacle, in a weather-resistant, in-use cover. Often on the garage or a bathroom circuit already, in which case it may already be protected.
All receptacles in unfinished space. The sump pump outlet is the one people try to leave off, and the code has closed that door.
Within six feet of the sink, and the laundry circuit itself under the current code. One circuit, one device.
Not required, but a GFCI is also the legal way to replace a two-prong outlet that has no ground, which makes it the answer to most old-house wiring questions.
Circuits, if you know them
Leave blank and the usual count for each area is assumed. Two bathrooms on one breaker are one circuit and one GFCI.
Usually 1.
Usually 2.
Usually 1.
Usually 1.
It has to be the first on the run. Tracing it is the part worth paying for.
Grounded three-prong outlets already.
At the first outlet, which resets at the wall.
Trip charge plus minutes per device.
Used only to pick a regional labour rate. It stays in your browser.
10 outlets on 5 circuits
5 GFCIs
$827 · 5 protected behind them · one per outlet would be $842
5 devices protect 10 outlets
A GFCI wired through its LOAD terminals protects everything after it on the same circuit. The other 5 outlets are ordinary receptacles with a sticker — which is the arithmetic the shop does not do for you.
The two terminals
LINE from the panel. LOAD to the rest.
Swap them and the GFCI usually still powers its own face, protects nothing behind it, and often refuses to reset. That is how a wired-backwards GFCI hides for years. After fitting, press TEST and check that the downstream outlets go dead — not just the GFCI itself.
By circuit, one per outlet, or from the panel
The same outlets, three ways.
What to buy
- 5 GFCI receptacles, 5 ordinary behind them
A 15 or 20 A GFCI receptacle. The dearer ones are tamper-resistant, weather-resistant or self-testing, and the last is worth having. A standard receptacle for the protected outlets downstream — plus the little sticker that says GFCI PROTECTED, which the code asks for.$127 - Fitting them, and tracing which outlet is first
Tracing is what an electrician does in minutes with a tester, and it costs almost as much per circuit as a spare GFCI would.$540 - Trip charge
The same for one circuit as for all of them. Do the whole house in one visit.$160
What it costs
National average. 5 GFCI receptacles protecting 10 outlets on 5 circuits, in one visit. Not included: new circuits or cable runs, a panel that has no spare space, or aluminium wiring.
If the panel itself is the problem — no spare breaker space, or a service that cannot take another circuit — that is a different job, and the wire that feeds any new run is sized here.
Worth knowing
- 10 outlets need protecting and they sit on 5 circuits, so the number of GFCIs is 5, not 10. A GFCI wired through its LOAD terminals protects every outlet after it on the same run; the other 5 are ordinary receptacles with a sticker. Here the saving is only $15, and honestly so: nobody knows which outlet is first, and tracing each circuit costs almost what a spare GFCI does. Know the first outlet and it is $290.
- Nobody knows which outlet is first on the run, and it has to be the first one — a GFCI protects downstream, never upstream. An electrician traces it in a few minutes with a tester; on your own it is the breaker off, and working out which outlets go dead in which order. It is the one part of this that is genuinely easier to pay for.
- The LINE and LOAD terminals are the entire job. LINE takes the feed from the panel; LOAD feeds the outlets you want protected. Swap them and the GFCI will usually still power its own face, protect nothing behind it, and in many models refuse to reset — which is how a wired-backwards GFCI hides for years. Test the downstream outlets with the button after fitting, not just the GFCI itself.
- Outdoor receptacles need a weather-resistant GFCI and an in-use cover — the bubble that closes over a plugged-in cord. The cover is about $22, it is required, and it is the item most often missing when the house is inspected.
- Every location here is one the code requires GFCI protection in. That matters twice: it is what a home inspector lists, and it is what an insurer asks about after a fault. The trip charge is the same for one circuit as for all of them, so do the whole list in one visit.
On this page — 4 sections
Count circuits, not outlets
The short version
- One GFCI protects everything downstream on its circuit. Ten outlets on five circuits is five devices.
- LINE from the panel, LOAD to the rest. Backwards, it works and protects nothing.
- A GFCI is the legal fix for two-prong outlets with no ground, with the label from the box.
- The trip charge is the job. $160 of a $234 bathroom.
Walk into a shop with a list of ten outlets that need GFCI protection and you will walk out with ten GFCIs. It is a reasonable-looking purchase and it is roughly twice what the wiring needs.
A GFCI has two pairs of terminals. LINE takes the feed from the panel. LOAD feeds onward to the next outlet — and everything on the LOAD side, all the way to the end of the circuit, is protected by that one device. The bathroom with six outlets on one breaker needs one GFCI at the first outlet and five ordinary receptacles with a sticker.
So the number that decides the bill is how many circuits those outlets sit on. A bathroom is usually one; a kitchen countertop is usually two; the garage, the outdoors and the basement are often one each and sometimes one between them.
| Location | Outlets | Circuits | GFCIs |
|---|---|---|---|
| Bathroom | 2 | 1 | 1 |
| Kitchen countertop | 5 | 2 | 2 |
| Garage | 2 | 1 | 1 |
| Outdoors | 1 | 1 | 1 |
| A typical house | 10 | 5 | 5 |
The shop sells the second column. The wiring needs the last one.
National Fire Protection Association, NEC 210.8 — Ground-fault circuit-interrupter protection for personnel, and 406.4(D) — replacement receptacles (2023) · checked 2026-09-23
It has to be the first outlet — and that is the part worth paying for
Protection runs downstream only. Put the GFCI at the third outlet on the run and the first two are exactly as unprotected as before, with a device on the wall that says otherwise.
Finding the first outlet is the one genuinely skilled minute in the job. An electrician does it with a tester and the breaker; on your own it is switching the breaker and working out which outlets die in which order — and being wrong is invisible until it matters.
It also changes the arithmetic honestly. When nobody knows which outlet is first, tracing each circuit costs about what a spare GFCI would — so the saving from counting circuits shrinks to almost nothing. Know the first outlet, and it comes back.
| Know the first outlet | Nobody knows | |
|---|---|---|
| The same 10 outlets, 5 circuits | $552 | $827 |
| Against one GFCI per outlet | $842 | $842 |
| What counting circuits saves | $290 | $15 |
| From the panel instead | $947 | $947 |
| Where a trip resets | At the wall | At the wall |
5
Devices for 10 outlets
One per circuit
$552
Fitted, first outlets known
$827 when traced
$160
The trip charge
The same for one or all
$25
A bathroom yourself
Two-prong, no ground, done legally
MaterialsEstimator, GFCI receptacle and breaker price survey · checked 2026-09-23
No ground? This is the legal fix
Every house wired before the early sixties has two-prong outlets and no ground wire behind them. Rewiring is the thorough answer and it is a whole-house price. The code offers a cheaper one, and it is not a loophole.
An ungrounded receptacle may be replaced with a GFCI — or with an ordinary three-prong receptacle downstream of one — provided it carries the No Equipment Ground label that comes in the box. The GFCI does not create a ground. It makes the outlet safe without one, by tripping the moment current goes anywhere it should not.
What it does not do is give a surge protector a path to ground, which is the honest limitation and the reason the label exists: it tells the next person exactly what they have.
On the day
- Breaker off, and test the outlet dead before touching a wire — with a tester, not by assumption.
- Identify the feed. If there is only one cable in the box, that is it. If there are two, the one that is live with everything else disconnected is the feed.
- LINE terminals take the feed. LOAD terminals take the cable onward. The strips of tape over LOAD in a new box are there to make you think about it.
- Press TEST after the breaker is back on, and check the downstream outlets go dead too — not just the GFCI.
- Sticker every protected outlet behind it: GFCI PROTECTED, and NO EQUIPMENT GROUND where there is none.
- Outdoors: weather-resistant device, in-use cover. Both required, both forgotten.
- More than two cables, aluminium wiring, or a feed you cannot identify — stop, and ring somebody.
What goes wrong
01Buying one GFCI per outlet
Protection runs down the circuit. Ten outlets on five circuits need five devices; the other five are ordinary receptacles with a sticker.
Instead — Count the circuits with a tester and the breaker before going to the shop.
02Fitting it at the wrong outlet
A GFCI protects downstream only. At the third outlet on the run, the first two stay unprotected with a device on the wall saying otherwise.
Instead — Find the first outlet on each run. It is the one minute worth paying an electrician for.
03Wiring LINE and LOAD backwards
The device powers its own face, protects nothing behind it, and usually will not reset. Everything works and nothing is safe.
Instead — LINE from the feed, LOAD to the rest, then press TEST and confirm the downstream outlets go dead.
04Calling an electrician out for one outlet
The trip charge is about $160 and the minutes on the device are few. One outlet costs almost what the whole list does.
Instead — List every required location in the house and do them in one visit.
05Rewiring a house to fix two-prong outlets
The code allows a GFCI, labelled No Equipment Ground, to replace an ungrounded receptacle. It is legal, it is safe, and it is a fraction of a rewire.
Instead — Use the GFCI fix, and understand that it does not give surge protectors a ground.
06An ordinary GFCI outdoors, with a flat cover
It corrodes and nuisance-trips within a couple of winters, and a flat cover is not compliant with a cord plugged in.
Instead — Weather-resistant device and an in-use bubble cover. It is the item inspectors flag most.
07Replacing a GFCI that keeps tripping
It is usually tripping on a real fault downstream — a damp box, a failing appliance — and a new device trips on the same fault.
Instead — Trace what is downstream and find what is leaking before buying anything.
08Trusting an old GFCI that never trips
Pre-2015 devices can fail silently and keep passing power. Never tripping is not the same as working.
Instead — Press TEST monthly, and replace anything that does not click off — new devices self-test.
- 01List every location the code coversBathrooms, kitchen countertops, anything within six feet of a sink, garage, outdoors, unfinished basement and crawl space, laundry.
- 02Count the outlets in eachThat is the number the shop will sell you. It is not the number you need.
- 03Count the circuits insteadFlip breakers with a tester in the outlets. Two bathrooms that go dead together are one circuit and one GFCI.
- 04Find the first outlet on each runWith the breaker on, the GFCI must go where the feed arrives first — a GFCI protects downstream only. This is the step worth paying an electrician for.
- 05Wire LINE from the feed, LOAD to the restThen press TEST and check the downstream outlets go dead, not just the GFCI.
- 06Label what is downstreamThe GFCI PROTECTED stickers in the box go on the ordinary outlets behind it. Inspectors look for them.
- 07If there is no ground, use the other labelA GFCI can legally replace a two-prong outlet. The No Equipment Ground label goes on, and it does not create a ground — it makes the outlet safe without one.
Protecting from the panel needs breaker space, and a house that is out of it — or on a service that cannot take another circuit — has a bigger decision to make than where a GFCI goes.
If the panel is the problem- GFCI
- Ground-fault circuit interrupter. It compares the current going out on the hot with the current coming back on the neutral and trips in milliseconds if they differ — which means some of it is going through something else, possibly you.
- LINE and LOAD
- The two pairs of terminals on the back. LINE takes the feed from the panel; LOAD feeds the outlets downstream that the device protects. Swapping them is the classic error and it hides for years.
- Downstream
- Every outlet on the circuit after the GFCI, in the direction of current flow. All of it is protected by the one device, and all of it is an ordinary receptacle with a sticker.
- First outlet on the run
- The receptacle the feed reaches before any other on that circuit. It is the only place a GFCI protects the rest, and finding it is what the tracing charge is for.
- GFCI breaker
- The same protection installed in the panel, covering the whole circuit with one device. Dearer than a receptacle, and it resets at the panel rather than at the wall.
- Dual-function breaker
- GFCI and arc-fault protection in one breaker — what a new kitchen or laundry circuit is required to have anyway.
- No Equipment Ground
- The label that comes in the box, applied when a GFCI replaces a two-prong outlet that has no ground wire. It tells the next person that the outlet is protected but not grounded, which is legal and which matters for surge protectors.
- In-use cover
- The bubble cover on an outdoor receptacle that closes over a plugged-in cord. Required, and the item most often missing at inspection.
- Weather-resistant
- A GFCI rated for outdoor boxes, marked WR. The ordinary one corrodes and nuisance-trips within a couple of winters.
- Tamper-resistant
- Shutters behind the slots that only open when both are pushed together. Required on nearly every receptacle in a dwelling under the current code.
- Self-test
- A GFCI that tests its own electronics periodically and shows a light if it has failed. Required on new devices since 2015, and the reason an old one that never trips is not necessarily working.
- Trip charge
- What an electrician charges for the visit, around $160. The minutes on a GFCI are few; the trip is the job, which is why the whole house goes in one visit.
Common questions
- How much does it cost to install a GFCI outlet?
- About $234 for an electrician to fit one in a bathroom — of which $160 is the trip charge and the device is about $21. Doing it yourself is the price of the device. The number that actually decides the bill is how many you need, and that is circuits, not outlets: ten outlets across a bathroom, kitchen, garage and outdoors are 5 GFCIs and about $552 fitted.
- Do I need a GFCI at every outlet?
- No, and this is the whole page. A GFCI wired through its LOAD terminals protects every outlet after it on the same circuit. The first outlet on the run gets the GFCI; the rest are ordinary receptacles with a GFCI PROTECTED sticker. A bathroom on one circuit needs one device however many outlets it has. Ten outlets on five circuits is five devices — and buying ten is $290 spent on protection you already have.
- Which outlet gets the GFCI?
- The first one the feed reaches on that circuit, because protection only runs downstream. With the breaker off and a tester, an electrician finds it in minutes; on your own it is switching the breaker and working out which outlets die in which order. If nobody knows, the tracing is the part genuinely worth paying for — it costs about what a spare GFCI does, per circuit.
- What happens if LINE and LOAD are wired backwards?
- The GFCI usually still powers its own face, protects nothing behind it, and in many models refuses to reset. It is the classic DIY mistake and it is invisible: everything works, nothing is protected. After fitting, press TEST and confirm the downstream outlets go dead, not just the GFCI itself.
- Where does the code require GFCI outlets?
- bathroom, kitchen countertop, garage, outdoors, unfinished basement or crawl space, laundry area — and anything within six feet of a sink. It is what a home inspector lists on a sale, and the trip charge is the same for one circuit as for all of them, so the whole list goes in one visit.
- Can I replace a two-prong outlet with a GFCI?
- Yes — it is the legal way to do it. The code allows an ungrounded receptacle to be replaced with a GFCI, or with a three-prong receptacle downstream of one, provided it carries the No Equipment Ground label from the box. It does not create a ground; it makes the outlet safe without one. For most pre-1960s houses this is the answer to the two-prong question, and it is $25 of parts for a bathroom.
- GFCI outlet or GFCI breaker?
- A breaker protects the whole circuit from the panel with one device — about $75 against $21 — and resets at the panel, which in a bathroom at night is a walk. On this house it is $947 from the panel against $827 at the outlets when nobody knows which outlet is first, and $552 when somebody does. Breakers win where the first outlet is hard to reach or where a new circuit needs arc-fault protection anyway.
- Why does my GFCI keep tripping?
- Usually because it is doing its job: a damp outdoor box, a failing appliance, a downstream outlet with moisture in it. Sometimes because it protects far more than anybody realised — a garage GFCI feeding the outdoor outlets and a shed. Trace what is downstream before replacing the device; a new one trips on the same fault.
- Can I install a GFCI myself?
- It is one of the few electrical jobs genuinely within reach. Breaker off, test dead, note which cable is the feed, LINE from it, LOAD to the rest, TEST button afterwards. It stops being a first job if there are more than two cables in the box, if the wiring is aluminium, or if you cannot identify the feed.
- What is the difference between a GFCI and an AFCI?
- A GFCI trips on current leaking to ground — the shock hazard. An AFCI trips on the signature of an arc — the fire hazard. Kitchens and laundries now need both, which is what a dual-function breaker provides. A GFCI receptacle does nothing about arcs.
- Do outdoor outlets need anything else?
- A weather-resistant GFCI, marked WR, and an in-use cover — the bubble that closes over a plugged-in cord. The cover is about $22, it is required, and it is the single item most often missing when a house is inspected.
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About the author
Pablo Ruiz Quintero — Editor
Editor of MaterialsEstimator. Decides which documents count as a source, what every default value is, and where the line sits between what the reader parses and what the engines compute.
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