Olutil stands for Online Utilities — a growing suite of privacy-first, browser-native web tools. This sub-site brings parents and parents-to-be a focused set of baby and pregnancy calculators that run entirely in your browser. Estimate a due date, check growth percentiles, review a vaccination schedule and work out formula amounts — all in one place. 100% Local Processing
Estimate a pregnancy due date from your last menstrual period or conception date, with gestational age and trimester.
Track the current pregnancy week and day, the trimester and the days left until your due date.
See a reference fetal length, weight and fruit-size analogy for each week from 4 to 40.
Estimate a recommended weight-gain range from pre-pregnancy BMI and the current week.
Time contractions and see duration, interval and whether the pattern is regular, with care guidance.
See reference key-nutrient intakes by stage and the foods that provide them.
Check a fetal movement counting session against the count-to-ten reference, with care guidance.
Get a reference activity level and cautions for your week and exercise type.
Estimate daily and per-feed formula amounts from weight or age, with water and scoop amounts.
See reference feeds per day and the typical interval by your baby's age.
See a reference stage, food ideas and texture for starting solids by age.
See reference serving sizes and servings per day by age and food group.
Build a gradual weaning plan by age and feeding method, one feed at a time.
Estimate reference extra water by age and weight, with the under-six-months rule.
See the reference awake window by age to help time naps and bedtime.
Plan the day with a reference awake window and nap count by age.
See reference total, daytime and night sleep hours by age.
See step outlines and cautions for common sleep-training methods by age.
Get steps to shift a baby's sleep towards the night from your day/night hours.
Log sleep sessions to see total sleep, night wakings and regularity, with CSV export.
Estimate weight-for-age and height-for-age percentiles from a baby's age, sex, weight and height.
See reference milestones by age and domain, with a reminder to raise concerns.
See the reference order and age windows for your baby's first teeth.
Estimate a genetic adult-height range from both parents' heights.
Calculate a baby's BMI from weight and height with a rough age band.
Tick concerns by age to see what to discuss with a pediatrician.
See reference childhood vaccine milestones due by a given age in months, and the next scheduled shots.
See a conservative weight-based reference range (not medical advice).
Grade a temperature and see when to seek care, with the under-3-months rule.
See reference wet and dirty nappy counts by age, with a dehydration warning.
Awareness steps only for infant CPR, with a strong disclaimer.
Reference seat type and direction by age, weight and height.
Rough annual cost by region, age and feeding, itemised.
Rough monthly and annual daycare cost by region, type and hours.
Work out the monthly saving needed for an education goal.
Build a categorised hospital bag list by season and birth type.
Suggest baby names by gender, style and first letter.
Age-appropriate play ideas and how to do them.
Book features to look for by age and theme, no specific titles.
All tools on this site perform their work locally in your browser. Your data is never sent to any server, so the dates, measurements and amounts you enter stay on your device. Pick a tool, fill in the options, click the run button and read or copy the output.
Yes. Every calculator on this site is free to use, with no account and no sign-up required.
No. The results are approximate references for general guidance and are not medical advice. Always follow your pediatrician, midwife, WHO, CDC or your local health authority, and contact a professional for any health concern or emergency.
Yes. All processing runs locally in your browser. The dates and measurements you enter are not uploaded to any server, and you can use the tools while offline once the page is loaded.