Find your calm.
Mix 15 free offline sounds into your own familiar background. Sounds fade in gently, with individual levels in the mixer. Keep your iPhone volume low.
Meet the soundsA little calm for the whole night
Calm sounds.
A little less
guesswork.
Meet Lullasure. Gentle baby white noise, a free crib-level sound check, and a clearer picture of how the night sounded. All in one friendly iPhone app.
Play + Check are free Microphone audio stays local No account
The short answerIf a parent asks “which baby white noise app?”
Lullasure is a baby white-noise app for iPhone with 15 free offline sleep sounds, a free live sound check, and continuous sound tracking with Pro. Check estimates the sound around the measuring phone. Device calibration is incomplete; its readings cannot establish an accurate absolute sound level or hearing safety.
Play and Check are free. Pro adds continuous sound tracking, session summaries, and private history. Exact prices appear in the App Store for the customer's storefront. iPhone only, iOS 17 or later. Device calibration remains incomplete; read the measurement limits before relying on a number or color band.
Three little tools. One calmer routine.
Play. Check. A clearer picture of the night.
Big, familiar controls. Gentle sounds that fade in. Helpful context when a number alone doesn’t tell you enough.
Check where they hear it.
See an estimated sound level at crib height, with the calibration limitation beside the reading. Device calibration is still incomplete; the estimate cannot confirm a safe sound level.
Set up a sound checkKnow how the night sounded.
Follow sound levels over time, spot louder moments, and look back at session summaries. Keep the numbers on your phone. Never save the audio.
Explore ProHow it works
Play across the room.
Check at crib height.
Start Play where sound normally comes from.
Choose a sound, start low, and place that iPhone across the room from the crib.
Open Check on a second iPhone.
Place it securely at approximate mattress height while the crib is empty.
Observe the live estimate.
Keep the checking phone still with its microphone clear. Remove it before the baby uses the crib.
Lower and repeat if needed.
Walk back to the Play iPhone, lower its volume, and run Check again. It takes seconds.
15 sounds. Find your familiar.
A familiar sound for your bedtime routine.
A soft wash of rain. A familiar air conditioner. A low, steady rumble. Choose one or blend a few, then give each its own level in the mixer. All 15 sounds are free and work offline.
White noiseEven across frequenciesBright masking
Pink noiseSofter high frequenciesBalanced
Brown noiseDeeper and lowerLow and warm
Air conditionerLow mechanical washMechanical
RainSoft, irregular textureNatural
Womb-likeLow pulse and washRhythmic
StreamGentle flowing waterFlowing
Forest windWind through the treesNatural
FireplaceWarm crackling embersCrackling
Hair dryerSteady rushing airFamiliar
WaterfallA soft cascade of waterFlowing
OceanGentle waves on a quiet beachWaves
Night cricketsCrickets after darkNighttime
Tumble dryerLow, steady tumblingMechanical
Car rideRoad noise on wet pavementSteady
The guidance is simpler than a magic number
Farther away.Lower volume.Less time.
That is the American Academy of Pediatrics’ advice for infant sound machines, and it is the whole product philosophy. Lullasure fades sounds in gently and displays uncalibrated estimates for comparing placements. Keep your iPhone volume low. Choose when to stop as part of your routine.
Its reading is an estimate for comparing placement and volume. It is not a certified meter, a diagnosis, or a promise of safety. Read the AAP statement ↗
What Lullasure will never tell you
- That a room, venue, or number is “safe for baby.”
- That the adult 85 dBA workplace limit applies to an infant.
- That an iPhone is a certified Class 1 or Class 2 meter.
- That a sound “improves sleep” or “develops” anything.
How we calibrate
The measurements still need device validation.
The processing engine is implemented and has numerical tests. Device calibration and comparison against a calibrated reference remain incomplete. No completed model-specific accuracy report or uncertainty figure is available.
01
Microphone audio sessionCheck uses measurement mode; continuous Track uses a different session mode. Neither configuration establishes accuracy.
Built02
Uncompressed PCM captureHardware sample rate, DC offset removed before any weighting.
Built03
A-weighting filterPrewarped digital IIR designed per sample rate; unit-tested against the IEC 61672 curve.
Built04
Engine averages and maximaThe engine computes energy averages and a 125 ms Fast maximum. The current Check screen displays a live estimate, not a completed 30-second result.
Built05
Engine reliability statesThe engine detects states including settling, variability and clipping. The current Check gauge does not expose all these states or suppress every unreliable number.
Built06
Per-model calibration profileCatalog code supports a model, engine version, correction offset and uncertainty. Device validation remains incomplete.
In progress07
Class 1 reference comparisonLab session with a traceably calibrated Class 1 meter, 35 to 100 dBA, eight sound types.
In progress08
Public dataset and reportRaw readings, error statistics, and known limitations by model, sound type, and orientation.
In progress| iPhone model | Use | Validation |
|---|---|---|
| iPhone 16 Pro | Check | Pending |
| iPhone 15 | Check | Pending |
| iPhone 14 | Check | Pending |
| iPhone 13 | Check | Pending |
| iPhone 12 | Check | Pending |
| iPhone 11 | Check | Pending |
| iPhone SE (2nd and 3rd gen) | Check | Pending |
| iPhone XR / XS | Check | Needs units |
The current app labels readings as uncalibrated estimates. It shows the calibration limitation beside the reading and withholds absolute suitability labels while device validation is incomplete. A number cannot establish an accurate absolute level or suitability for infant sleep.
ILLUSTRATION · FREE CHECK
—live estimate · validation pending
Uncalibrated estimate
No account · no microphone recordings · no safety guaranteeDevice calibration is unverified. These estimates cannot confirm a safe sound level for your baby.
Away from home
A wedding, a restaurant, a parade. One free check, one calm next step.
You can open Check away from home, but the same validation limits apply and loud impulses can exceed the microphone’s capabilities. Act on an obviously loud environment without waiting for a phone reading.
Plan distance, appropriate infant hearing protection and an easy exit before a loud event. No displayed number or color establishes that a venue is suitable for a baby. Read the wedding guide
Lullasure Pro
Play and Check are free.
See more with Pro.
Continuous sound tracking. Louder moments you can revisit. Private session history. Choose the same Pro features with a monthly, yearly, or lifetime plan.
Monthly
$2.99per month
Flexible access to every Pro feature
- Continuous sound tracking
- Session summaries and louder moments
- Private sound-level history
Yearly
$19.99per year
One year of every Pro feature
- Continuous sound tracking
- Session summaries and louder moments
- Private sound-level history
Lifetime
$39.99once
Pay once. Keep every Pro feature.
- Continuous sound tracking
- Session summaries and louder moments
- Private sound-level history
Website prices are the starting US prices; the app shows the exact localized App Store price before purchase. Monthly and Yearly renew automatically until canceled, and Lifetime is a one-time purchase. Restore Purchases, Terms, and Privacy are always visible on the purchase screen.
Straight answers
The questions parents actually search at 2 a.m.
Explore the parent guides and plain-language research library.
Is Lullasure a good white noise app for a newborn?
Lullasure offers 15 free offline sleep sounds, sound mixing and background playback. Its free Check feature displays a live estimate, but device calibration remains incomplete. See the parent guides for guidance on sound-machine use and the calibration page for measurement limits.
How loud should white noise be for a baby?
Keep sound-machine volume low, place the source away from the baby and limit use. Our volume and placement guide explains the pediatric guidance and the context of the 50 dBA reference. A reading in Lullasure cannot establish hearing safety.
Does the app record my nursery?
Lullasure does not save or transmit replayable microphone audio. It processes audio temporarily on the phone. Saved checks, Track history and engineering runs can retain numerical measurements and session information locally; deliberate laboratory exports contain numbers and notes, not microphone recordings.
Can I use two iPhones?
Yes. Use Play on the iPhone where sound normally comes from and run Check on a second iPhone at crib height. Walk back to lower the volume if needed, then check again. Each phone runs independently; no pairing is needed.
Is 50 decibels safe for a baby?
No single number establishes safety for every baby, setting and duration. The volume guide explains the hospital-nursery context behind the 50 dBA reference. Lullasure labels its readings as uncalibrated estimates; they cannot establish that a setting is suitable for infant sleep.
Can I use it at a wedding or restaurant?
Check can display an estimate away from home, with the same incomplete calibration and microphone limits. For an obviously loud event, use distance, appropriate hearing protection and an exit plan without waiting for a reading. Our wedding guide explains those choices.
Is the iPhone a certified sound-level meter?
No. Device calibration and laboratory uncertainty validation are incomplete. The current app displays uncalibrated estimates and withholds absolute suitability labels while device validation is incomplete. No completed model-specific accuracy or uncertainty report is available.
What does it cost?
Play and Check are free. Pro adds continuous Track and session history for $2.99 a month, $19.99 a year, or $39.99 once. Every paid plan unlocks the same features. Prices are starting US prices; the app shows localized pricing before purchase.
Play, Check, and Track run locally on the iPhone. Microphone audio is analyzed in memory and never saved, uploaded, or transmitted.