CLINICAL CALCULATOR & IPHONE APP

Breastfeeding & alcohol calculator: know when your milk is clear, with peace of mind.

Conservative clearance estimates grounded in peer-reviewed pharmacokinetics (Ho et al., 2001; Watson, 1980; NIH LactMed & CDC), expressed milk stash planning, and a discreet minute-by-minute countdown on your iPhone Lock Screen.

Quick milk clearance & expressed stash estimator

Estimated clearance window (zero-trace safety margin) ~2h 45m to 3h 15m
Suggested expressed milk reserve (30–35 mL/h) 80 to 110 mL (2.7–3.7 fl oz, split ≤ 120 mL slow-flow bottles)
Over 4h wait: if your breasts feel full, express just enough for comfort and supply protection (pumping does not speed clearance; discard milk expressed during active countdown).

WHY 100% OF EVENING PEACE OF MIND HAPPENS IN THE IPHONE APP

Built for real dinners, weddings & 2 AM feeds — not math at the table

  • 🔒 Discreet Lock Screen & Dynamic Island Live ActivityShows exact minute-level “Ready at 23:42” at a glance without unlocking — zero mention of alcohol on your screen.
  • 🍷 1-Tap “Oops, +1 drink” staggered recalculationAdded a toast or second glass an hour later? Recalculates staggered liver clearance in <200ms using your exact height & weight.
  • 🗓️ Reverse Evening Planner & split-bottle checklistCheck how much you can sip before a planned feed + exact slow-flow bottle stash prep so zero liquid gold goes to waste.
  • 🤝 1-Tap Co-Parent Live Relay & 2 AM SOS Soothing GuideSend a live no-app countdown link via WhatsApp/iMessage + calm soothing steps if baby refuses the bottle mid-timer.

💛 One-time Breastfeeding Pass ($14.99 / £12.99) — zero mandatory subscription, zero ads, 100% offline. Cheaper & more reliable than a single $20 box of alcohol test strips prone to false positives.

📲 Get MamaClear on the App Store (Includes 1 Free Check) Already installed? Open my calculation directly in MamaClear →
🔒 100% offline on your iPhone · Zero account · Zero cloud tracking Preview live co-parent night relay →

Reference breast milk alcohol clearance chart by maternal weight

Computed with the MamaClear STRICT_ZERO model (reference height 165 cm / 5'5", Watson 1980 female Total Body Water clamped to [0.42, 0.58], Ho et al. 2001 zero-order clearance rate of 0.015 g/dL/h, 15-min absorption lag, and universal 1h 15m post-drink safety floor). Drinking with a meal lowers peak milk concentration by up to ~1/3 without speeding zero-order liver elimination.

Maternal Weight (Body Water) Toast Sip (50 ml Bubbles 12%) Standard Pour (100 ml Wine 12.5%) Generous Pour (120 ml Wine 13%) 2 Staggered Glasses (t=0 & +60m, 120 ml 13%)
50 kg (110 lb)TBW 27.9 L 1h 23m 2h 37m 3h 11m 6h 07m
60 kg (132 lb)TBW 30.3 L 1h 17m 2h 25m 2h 57m 5h 39m
70 kg (154 lb)TBW 32.8 L 1h 15m(1h 15m floor) 2h 15m 2h 45m 5h 15m
80 kg (176 lb)TBW 35.3 L 1h 15m(1h 15m floor) 2h 07m 2h 35m 4h 55m

Expressed milk stash, horizontal bottle rule & melatonin cheat-sheet

Volume · 30–35 mL (1–1.25 oz) / hour

Split your stash into ≤ 120 mL (4 oz) bottles

Exclusively breastfed babies aged 1–6 months take ~30–35 mL per hour away. Never warm one huge bottle: prepare smaller 90–100 mL bottles plus a 40–50 mL backup in the fridge so unconsumed breast milk is never wasted.

Protect nursing latch

Paced horizontal slow-flow bottle feeding

Use an extra-slow newborn nipple (size 0 / XS), hold baby upright, and keep the bottle nearly horizontal with gentle pauses. Baby actively regulates milk flow just like at the breast, preventing bottle flow preference.

Chrononutrition · Day vs Night

Evening melatonin milk vs. midday cortisol milk

Breast milk expressed in the evening or night contains higher natural melatonin and tryptophan to support infant sleep, whereas midday milk carries alerting cortisol. Still, daytime milk is 100% safe and nutritious whenever needed!

Safe Storage (CDC / LLL)

Freshly expressed milk storage windows

Up to 4 hours at room temperature (≤ 25°C / 77°F), up to 4 days at the back of the fridge (≤ 4°C / 40°F), and 4–6 months in a deep freezer (-18°C / 0°F). Use warmed or partially finished bottles within 1–2 hours.

🖨️ Open Printable IBCLC / Midwife Fridge Cheat-Sheet (Storage & Paced Bottle Rules) →

Evidence-based breastfeeding & holiday planning guides

Read our clinical deep-dives referencing Motherisk (Ho et al., 2001), NIH LactMed, CDC, and La Leche League for Thanksgiving, Christmas, weddings, and evenings out.

Browse all English breastfeeding guides →

Clinical FAQ: Breastfeeding, Alcohol Clearance & Infant Safety

How long after 1 glass of wine or champagne can I breastfeed safely?

For a 100 mL European pour of 12.5% wine (~9.9 g pure ethanol), zero-level clearance takes between 2h 07m (80 kg / 176 lb mother) and 2h 37m (50 kg / 110 lb mother) under the Motherisk nomogram (Ho et al., 2001, PMID: 11585986) paired with Watson (1980) female Total Body Water. A standard 5 fl oz (150 mL) US pour of 13% wine (~15.4 g ethanol) typically clears in ~3h 05m to 3h 55m depending on maternal weight and height.

Does “pumping and dumping” remove alcohol from breast milk faster?

No. Alcohol equilibrates passively and continuously between maternal blood and breast milk. As your liver metabolizes blood alcohol back to zero, alcohol diffuses back out of breast milk at the exact same rate—without needing to empty your breasts (NIH LactMed, CDC, La Leche League). Expressing during an active timer is only needed to relieve uncomfortable fullness during waits over 4 hours.

Are breast milk alcohol test strips accurate, or why do they show false positives?

Colorimetric enzyme test strips cost ~$18–$22 per pack and use alcohol oxidase pads that frequently trigger on clinically negligible trace vapor, humidity, or pad oxidation—causing stressful midnight false positives. A peer-reviewed pharmacokinetic timer calibrated to your weight, height, exact ABV%, and drink timestamps gives a predictable clearance clock before you even take a sip.

How much expressed breast milk should I leave for a night out?

Plan roughly 30 to 35 mL (1 to 1.25 fl oz) per hour away for an exclusively breastfed baby aged 1 to 6 months. Always nurse right before your first drink to maximize clearance time before the next feed, and split totals above 120 mL (4 oz) into smaller slow-flow bottles plus a cold 40–50 mL backup.

Does giving daytime-pumped breast milk at night affect my baby’s sleep?

Evening and night breast milk naturally contains higher melatonin and tryptophan, while morning/midday milk has slightly higher cortisol. Pumping your backup bottle in the evening 1–2 days ahead is a great bonus for bedtime feeds, though daytime milk remains completely safe, healthy, and nourishing.

What extra precautions apply to newborns under 4 weeks and safe night sleep?

Newborns under 28 days metabolize ethanol at roughly half the adult hepatic rate and cluster-feed unpredictably, so abstaining completely is strongly advised during the first month. Regardless of infant age, never bed-share (co-sleep on the same surface) on any night either parent has consumed alcohol.

Peer-reviewed clinical & pharmacokinetic references

  • Ho E., Collantes A., Kapur B.M., Moretti M., Koren G. (2001) Alcohol and breast feeding: calculation of time to zero level in milk. Biology of the Neonate (Motherisk Program, Hospital for Sick Children, Toronto), 80(3), 219–222. · PubMed PMID: 11585986
  • Watson P.E., Watson I.D., Batt R.D. (1980) Total body water volumes for adult males and females estimated from simple anthropometric measurements. American Journal of Clinical Nutrition, 33(1), 27–39. · PubMed PMID: 6986753
  • National Library of Medicine — Drugs and Lactation Database (LactMed®) Alcohol (Ethanol) Clinical Monograph — National Institute of Child Health and Human Development (NIH). · NCBI Bookshelf: NBK501469
  • Centers for Disease Control and Prevention (CDC) Breastfeeding Special Circumstances — Maternal Diet & Alcohol Clinical Guidance. · CDC Breastfeeding & Alcohol
  • CRAT — Centre de Référence sur les Agents Tératogènes (Hôpital Trousseau, AP-HP) Alcool et allaitement : cinétique lactée et repères cliniques périnataux. · lecrat.fr
  • La Leche League International (LLLI) Drinking Alcohol and Breastfeeding — Evidence-based lactation & paced bottle-feeding guidance. · llli.org