Important: This predictor is for planning and education only. It does not diagnose a “sleep regression,” predict your baby’s health, or replace advice from your pediatrician. If your baby has breathing concerns, persistent fever, dehydration, weight-gain issues, or you’re worried about pain or illness, seek medical care.

What this calculator is estimating

Parents often use the phrase sleep regression to describe a temporary period when a baby who was sleeping more predictably begins waking more often, resisting naps, taking longer to settle, or shortening sleep stretches. These disruptions often coincide with developmental changes (new motor or language skills), shifts in sleep needs, or environmental changes.

This calculator provides a rough “likelihood score” based on four inputs:

• Age (months): certain ages commonly correspond to developmental changes that can disrupt sleep.
• Average nightly wakeups: more frequent wakeups can signal an active disruption period or an accumulating sleep debt.
• Routine consistency (0–10): more consistent schedules and bedtime cues can reduce night-to-night variability.
• Teething/illness: discomfort and congestion can temporarily increase wakeups and settling difficulty.

How the estimate is calculated (simple model)

The page uses a simplified linear scoring approach to turn your inputs into a percentage-like value. In plain language:

• Higher age and higher wakeups push the estimate upward.
• Higher routine consistency pushes the estimate downward.
• Teething/illness (if checked) should be treated as an added risk factor (temporary and highly variable).

One way to express the simplified core relationship is:

Where:

• A = age in months
• W = average nightly wakeups
• R = routine consistency score (0–10)
• P = an output that is interpreted as a percentage-like estimate after scaling/clamping (implementation details may cap results to a 0–100 range)

Note: Real sleep patterns are not linear and are influenced by many factors not captured here (feeding changes, naps, temperament, environment, travel, etc.). This model is intentionally simple so it stays understandable and quick to use.

How to use the inputs (practical definitions)

Baby age (months)

Enter your baby’s current age in months. If your baby was born premature, an adjusted age may align better with developmental timing; if you’re unsure, ask your pediatrician which age to use for development and sleep expectations.

Average nightly wakeups

Count wakeups where your baby is awake long enough to need help settling (feeding, rocking, pacifier replacement, reassurance, etc.). If your baby briefly stirs and resettles without help, many parents do not count that as a wakeup. Use a 3–7 night average for a steadier estimate.

Routine consistency score (0–10)

Use this as a quick self-rating:

• 0–3: bedtime varies widely; naps are unpredictable; bedtime routine often changes
• 4–7: some consistency; bedtime within ~30–60 minutes most nights; routine usually similar
• 8–10: strong consistency; bedtime and wind-down cues are very predictable

Teething or illness

Check this if you suspect discomfort (new teeth, ear pain) or illness (cough, congestion, fever) is affecting sleep. This does not mean the issue is “just regression”—it simply flags that a temporary disruption is more plausible.

Interpreting your result

Think of the output as a planning signal, not a medical or scientific probability:

• 0–30% (lower): regression-like disruption is less suggested by these inputs. If sleep is still difficult, consider nap timing, sleep environment, or habits that may be sustaining wakeups.
• 30–70% (moderate): mixed picture. You may be in (or approaching) a temporarily bumpy stretch. Keep routines steady, watch for overtiredness, and track patterns for 1–2 weeks.
• 70–100% (higher): your inputs resemble a higher-disruption pattern. Focus on consistency, comfort checks for illness/teething, and preventing sleep debt. If the pattern is intense or prolonged, consider professional guidance.

Also pay attention to the direction your inputs are moving week to week. A rising wakeup average or falling routine score often matters more than a single-day estimate.

Worked example

Example baby:

• Age: 9 months
• Average nightly wakeups: 3
• Routine consistency: 6
• Teething/illness: unchecked

Using the simplified formula:

• A/6 = 9/6 = 1.5
• W/10 = 3/10 = 0.3
• R/10 = 6/10 = 0.6

So P = 1.5 + 0.3 − 0.6 = 1.2. Depending on how the page scales this score into a percentage-like output (often multiplying by 100 and then clamping), that would correspond to a higher likelihood signal. The practical takeaway: wakeups are elevated and the baby is at an age where disruption is commonly reported; strengthening consistency (e.g., moving from 6 → 8) would reduce the estimate and often helps in real life, too.

Common regression windows and what you might see

Limitations and assumptions (read this)

• Not medical advice: sleep disruption can be caused by illness, reflux, allergies, ear infections, pain, or breathing problems. Don’t rely on a calculator to rule these out.
• Not a true probability model: the output is a simplified score that’s interpreted like a percentage; it is not trained on clinical data and does not provide a validated risk estimate.
• Doesn’t include key sleep drivers: nap timing/length, total sleep in 24 hours, feeding changes, sleep environment (light, noise, temperature), caregiver responses, and travel can dominate outcomes.
• Age is approximate: developmental timing varies widely. Prematurity/adjusted age and individual temperament can shift “windows.”
• Wakeup counts vary by definition: families differ on whether brief stirs count; use a consistent definition and a multi-night average.
• Checkbox is broad: “teething/illness” can range from mild discomfort to significant illness; the impact on sleep can be very different.

What to do next (planning checklist)

• Track 7 nights (bedtime, wakeups, naps) to confirm a pattern.
• Prioritize consistency for 10–14 days before making major changes.
• Protect against overtiredness (often worse sleep follows too-late bedtime).
• If symptoms suggest illness or pain, address comfort/medical concerns first.