Pregnancy & Fertility
Ovulation Calculator
Ovulation ≈ next period − 14 days
Estimate your fertile window and ovulation date for trying to conceive.
Open Calculator →Pregnancy Weight Gain Calculator
Pre-pregnancy BMI → IOM total-gain range
Recommended weight gain by pre-pregnancy BMI, with a week-by-week target band.
Open Calculator →Pregnancy Calorie Calculator
Maintenance + 0 / 340 / 452 kcal by trimester
Estimate daily calorie needs in each trimester (Mifflin-St Jeor + Institute of Medicine).
Open Calculator →These calculators support the months before InfantChart's growth charts become useful — the fertility and pregnancy stage. Estimate your most fertile days for trying to conceive, see the recommended weight-gain range for your pre-pregnancy BMI, and find how many calories you need each trimester.
They are supplemental to the site's core purpose — the WHO and CDC growth-percentile charts you'll use after your baby arrives. Each tool is an estimate based on published guidance from sources like ACOG, the CDC, and the Institute of Medicine, and none is a substitute for your healthcare provider.
When to use these calculators
Use the Ovulation Calculator when you're trying to conceive and want to identify your fertile window — not as a method of birth control. Use the Pregnancy Weight Gain calculator to check your gain against the Institute of Medicine ranges for your pre-pregnancy BMI, and the Pregnancy Calorie calculator to estimate daily energy needs by trimester. Once your baby is born, switch to the growth-percentile charts that are the heart of this site.
Frequently Asked Questions
- Are these pregnancy calculators a substitute for medical care?
- No. They provide general estimates based on published averages and guidelines (ACOG, CDC, Institute of Medicine) and are intended for planning and education. They cannot account for your individual medical history, and they are not a substitute for advice from your doctor or midwife.
- Can the ovulation calculator be used to prevent pregnancy?
- No. Calendar-based ovulation prediction is not reliable contraception — typical-use failure rates are high and it can result in unintended pregnancy. The calculator is a planning aid for trying to conceive. For contraception, talk to a healthcare provider about effective methods.
- How do these relate to the growth charts on this site?
- They cover the pregnancy and fertility stage that comes before growth tracking. After your baby is born, the WHO and CDC growth-percentile calculators — the main focus of InfantChart — let you track weight, length/height, head circumference, and BMI over time.