Here is the short version. Flip one branch-circuit breaker at a time while the house is running. Write down everything that turns off. Make each label clear enough that a stranger could use it. Do not copy the old labels without testing them. A guess written down as a fact is how a breaker box ends up lying to you.

This is a mapping job, not an electrical repair job. Operate only the breaker handles from outside the panel. Never remove the panel cover or touch anything inside it. If you see heat, corrosion, damage, or signs of arcing, stop and call a qualified electrician.

This guide walks through each step. By the end, you will have a list of what every breaker controls. Type that list into the free label generator and it formats a printable directory that fits inside your panel door. Open it in another tab and fill it in as you map.

Open the free label generator

What you need

A helper in the house to call out what turns off. Working alone? A loud radio does the job. You can hear it stop from the panel.
A plug-in lamp for checking outlets. An outlet tester is optional, but do not treat it as proof that a circuit is safe to touch.
Painter’s tape and a marker for quick notes.
An hour or two, ideally in daylight, plus a flashlight for the panel area.

Read the panel before you map it

Many U.S. residential panels have two columns of breaker positions. In the common layout, odd numbers go down the left and even numbers go down the right: slot 1 sits across from slot 2, and slot 3 sits across from slot 4. Do not assume that layout, though. Follow the numbers printed on your panel and the numbering shown on its directory; some panels number positions sequentially.

The card inside the door follows that same numbering. This card is called the circuit directory, or the panel schedule. If the old labels look shuffled to you, this numbering is usually why.

Breakers come in a few shapes. Know them before you start:

Single-pole breakers are most of your panel. On a typical U.S. residential panel, one handle and one position serve one 120-volt branch circuit. They commonly run lights and everyday outlets.
Double-pole breakers occupy two adjacent positions and may have a common handle or a handle tie. In a typical 120/240-volt home panel, they often serve 240-volt equipment such as a range, dryer, water heater, or central air conditioner. They can also serve two 120-volt loads on a shared-neutral branch circuit, so do not assume that every one feeds a single appliance.
Tandem breakers put two independent single-pole circuits in one position. Each handle is a separate circuit, but tandems are only permitted in panels and positions listed for them by the manufacturer.
Quad breakers vary by model. One may contain two single-pole circuits and one common-trip two-pole circuit, or two common-trip two-pole circuits. Use the breaker’s handle ties and markings to identify the circuit groups. Label each circuit, not automatically each handle.

How to find out what breaker controls what

Get the house talking. Turn on lights in every room. Include closets, the basement, and outside lights. Plug a lamp or radio into outlets that have no switch. Shut down computers and other sensitive electronics first. Do not deliberately interrupt medical equipment, security or fire systems, or a sump pump that is currently needed.
Start with clear dedicated loads. You can begin with two-pole breakers serving equipment that is running, but do not switch off the main breaker, a panel feeder, or solar, battery, generator, or transfer equipment as part of this process. If you are mapping central air, turn the thermostat off first and wait for the equipment’s restart delay before turning the breaker back on. A two-pole breaker may serve more than one load, so check the whole house rather than looking for only one appliance.
Then flip one branch-circuit breaker at a time. Turn one off. Walk the house, or have your helper call out what went dark. For a common-trip or handle-tied pair, operate the pair as one group. Turn a breaker back on only if nothing tripped and there are no unusual sounds or smells. One at a time keeps the picture clean.
Write down everything that turned off. Not just the first thing you noticed. One breaker might feed the living room lights, the porch light, and half the hallway outlets. The full list is the label.
Test outlets on their own. Lights and outlets in the same room are often on different circuits. Many newer homes have at least two small-appliance circuits serving kitchen countertop receptacles, and bathroom receptacles may share a circuit while the lights are elsewhere. Older homes and local codes can differ. Use the lamp to check each outlet; an outlet tester can help identify wiring conditions, but it is not a substitute for a qualified electrician.
Expect a few mystery breakers. The doorbell, the garage door opener, the sump pump, and the furnace like to hide. If a breaker seems to control nothing, write “unknown” as a temporary mapping note and move on. Mark a genuinely unused position as “spare.” Do not leave an active circuit marked “unknown” in the final directory; if you cannot resolve it safely, have an electrician identify it.

The fridge and freezer will generally be fine without power for a few minutes if you keep the doors closed, but do not interrupt equipment that must remain powered for health or safety. Map those circuits only when doing so is safe for the equipment and the household.

Write labels that stay true

A good label helps someone who is not you. Three rules get you there:

Name the thing, not the person. “Emma’s room” stops working the day Emma switches rooms. “Northeast bedroom” always works. The electrical code agrees: labels must be specific, and they cannot depend on who lives there (NEC 408.4(A)).
Note the exceptions. If one kitchen outlet is on a different circuit, say so. “Kitchen outlets (except coffee maker)” saves someone twenty minutes.
List everything on the circuit. “Living room lights, porch light, hallway outlets” is a real label. “Living room” is a rumor.

These rules work on paper. They work even better in an app the whole house can see. Tobi’s electrical panel schedule mirrors your panel slot by slot. Each circuit carries a flag: verified, a guess, or known wrong. The circuits you have not tested yet stay honest about it, and when someone pins down a mystery breaker, everyone’s phone gets the update.

Print a copy for the panel door

The panel door should always hold a directory people can read. The person dealing with a power loss will not check your notes app. The NEC calls for a legible, permanent, clear, and specific circuit description. The free panel label generator handles the formatting for standard U.S. residential panels. Pick your panel size, type in your labels, print the PDF, and secure it inside or next to the panel door. Verify that it fits your particular panel before relying on it.

Labels fade, so plan for it

Time is hard on a circuit directory. A renovation adds circuits. An electrician moves a few breakers around. The person who did the mapping moves out and takes the knowledge along. Paper cannot keep up on its own.

Give the directory a second home that is easy to update. That can be a shared record in Tobi or any place the whole house can reach. When something changes, fix it there the same day. Reprint the paper copy when it stops matching.

That is the whole method. One afternoon, one breaker at a time, and labels a stranger could understand. The next time a breaker trips, the directory can identify the circuit so whoever is home knows what lost power. Unplug or turn off obvious loads and reset the breaker only if there are no warning signs and it has not repeatedly tripped. If it trips again, leave it off and call a qualified electrician.

How to label your electrical panel the right way