Free medical calculators

Doctor-reviewed tools to help you follow each stage of your pregnancy.

Every calculator uses formulas published in the medical literature and is reviewed by Dr. Peterson Fernandes, radiologist at Derm Imagem. Results are estimates: take them to your obstetrician for interpretation.

Gestational calculator (EDD)

Calculate the estimated due date and gestational age from your last period or first ultrasound.

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Pre-eclampsia risk

Estimate the risk of early pre-eclampsia using blood pressure, uterine artery Doppler and PlGF.

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Down syndrome risk

Estimate the trisomy 21 risk from maternal age, crown-rump length and nuchal translucency.

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Fetal size by week

See your baby's length and weight for every week of pregnancy.

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Fertile window and ovulation

Find your most fertile days, ovulation and next period.

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Conception date

Estimate the conception date from your period, due date or ultrasound.

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How these calculators work

Each tool reproduces a model published in the obstetric literature and is tested against reference values before release. Nothing you type is stored: the calculation happens on the server and the page is discarded afterwards.

The calculators help you understand your scan report, prepare questions for your appointment and follow the pregnancy over time. They do not replace a medical assessment or an ultrasound.

Frequently asked questions

Yes. All calculators are free, require no sign-up and do not store the data you enter.

No. They are estimates produced by statistical models. Interpretation depends on your history, physical examination and other tests, and is always made by your doctor.

No. The values are sent to the server only for the calculation and are not written to a database, file or history.

Important notice

This calculator is an educational tool and does not replace a medical consultation. Results are estimates based on published models and may not apply to your case. Never make decisions about your health or your pregnancy without advice from your doctor.

Reviewed by: Dr. Peterson Fernandes — CRM-MG 42452 · RQE 37814

Last reviewed: 11/3/2026

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Ultrasound, Doppler and echocardiography in Ipatinga, Brazil, reported by Dr. Peterson Fernandes.

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