The full 7-night arc, night by night

The Ferber arc is a week. Each night the intervals lengthen, and each night the total crying typically drops. This guide walks through all seven nights so you can see the shape of the week before you are inside it.

Here is the whole table:

Night	First wait	Second wait	Third wait	Then repeat
Night 1	3min	5min	10min	10min
Night 2	5min	10min	12min	12min
Night 3	10min	12min	15min	15min
Night 4	12min	15min	17min	17min
Night 5	15min	17min	20min	20min
Night 6	17min	20min	25min	25min
Night 7	20min	25min	30min	30min

After the third interval, the third value repeats until your baby falls asleep.

The footnote on this table is the single most overlooked rule in the method: after the third interval each night, the third value repeats until your baby falls asleep. So Night 4’s tenth interval is fifteen minutes, not twenty. The waits get longer as the night goes on, but only inside the table. After the table runs out of columns, the third column is what you keep using.

Night 1

Loudest, shortest waits. Ten-minute wait at the third interval is usually the hardest single moment of the week. Most babies cry hard for the first fifteen minutes, settle within an hour, wake one to three times in the night. Each waking restarts at three minutes.

The full minute-by-minute is in the first night guide.

Night 2

Often louder than Night 1, sometimes the loudest night of the week. The baby has a small theory of what is happening and is testing it. The intervals lengthen tonight, which makes the longest wait longer than yesterday’s longest.

Total crying time usually drops slightly compared to Night 1, even though it feels worse in the moment. Time-to-asleep drops more reliably than crying duration on this night.

The full guide for Nights 2 and 3 is in the hard middle.

Night 3

The turning point for most families. Time-to-asleep drops by half on average. Many babies cry only through the first wait, then settle. Wakings through the night drop too.

Parenting Science’s review puts the typical Night 3 reduction in time-to-asleep at over fifty percent. The Sleep Foundation summary says the same.

If Night 3 is flat, run the diagnostic in the hard middle guide before you change anything.

Night 4

The waits step up to twelve, fifteen, seventeen. In practice most babies cry through the first wait or part of it, then settle. Total time-to-asleep on Night 4 is usually under fifteen minutes for families that had a clean Night 3.

Wakings tend to be shorter and less frequent. Some babies sleep through the night for the first time on Night 4. Some still wake once. Both are within normal.

The temptation tonight is to relax the protocol. Do not. The longer waits are part of what teaches the baby that mid-night wakings are also a solo activity. Skipping ahead now means the next minor disruption (a tooth, an illness) re-introduces wake-and-cry behaviour.

Night 5

Waits at fifteen, seventeen, twenty. By tonight, most parents are not seeing crying past the first wait at all. Drop-offs are quick. Wakings, if any, are short.

If your week has been on the typical curve, Night 5 is the night where you notice you are no longer dreading bedtime.

Night 6

Waits at seventeen, twenty, twenty-five. By this point the crying behavior has usually disappeared entirely. The waits are an insurance policy: if your baby has a fussy moment, the protocol is still in place, and the intervals mean you are not running back at the first sound.

Many families say Night 6 is the night their partner stopped sleeping in the spare room.

Night 7

Waits at twenty, twenty-five, thirty. Most babies are sleeping straight through. The thirty-minute wait at the third interval almost never gets used, which is the point. The protocol has done its job.

This is the last night of the formal arc. Tomorrow you sleep without a spreadsheet.

What you do after Night 7

Run the bedtime routine you established this week. Put your baby down drowsy but awake. If they cry, you know the protocol. The intervals you land on are essentially Night 7’s: roughly twenty minutes between checks, or whatever time-to-asleep your baby has settled into.

When a regression hits (and one will, around 8 to 10 months and again around 12 months), you can re-introduce the formal Ferber arc starting from Night 1 or, more commonly, from a middle night. Most families find the second arc takes two or three nights, not seven, because the protocol is already learned.

The sleep regressions guide has the playbook.

What if a night goes off-script

There are normal off-script nights:

• A growth spurt. More feeding, more wakings, a louder Night 4 than Night 3. Run the protocol the same way.
• A skipped nap. Bedtime is harder. Run the protocol; tomorrow night usually returns to plan.
• A trip or a houseguest. Some disruption is fine, lots of disruption blurs the signal. Hold the protocol.

There are stop-the-arc nights:

• A fever. Pause. Resume when the baby is fully recovered, ideally from the start of the same arc you were on, not from Night 1.
• A vaccination in the past 48 hours. Pause if there is a reaction.
• A milestone like rolling, sitting, or pulling to stand that is keeping your baby awake by accident. Pause for a few nights, then resume.

The troubleshooting hub covers the diagnostic flow if a specific night feels off.

What the app does across the week

The app’s most useful job is the trend chart. After Night 3 it shows the arc as an actual line going down, which is more reassuring than the day-to-day feel. The history is on-device, so the chart updates the moment you tap “fell asleep” on the previous night.

The widget shows the right intervals each night without you having to remember. The chime is the same calm tone every night. The check-in button logs every visit. None of that is essential to running Ferber, but all of it is the difference between running the protocol carefully and running it on dead reckoning at 3 a.m.