Women's Health Tools
Free women's health calculators including period tracker, due date calculator, ovulation calculator and bra size calculator.
Free women’s health calculators for cycle dates, fertile-window estimates, pregnancy milestones and bra sizing. Health estimates are supported by international sources including WHO, ACOG and NHS guidance and are not a substitute for clinical care.
Which calculator should I use?
Estimate fertile days
Use a last-period date and cycle length to estimate ovulation and a fertile window.
Ovulation CalculatorEstimate pregnancy dates
Calculate an estimated due date, pregnancy week and trimester.
Due Date CalculatorEstimate clothing size
Convert band and bust measurements across common sizing systems.
Bra Size CalculatorRelated Guides
All guides →Understand what cycle estimates mean
The period calculator and ovulation calculator project dates from the cycle information entered. The due-date calculator uses standard pregnancy dating conventions, while the bra-size calculator converts body measurements into a starting size. Each result is an estimate rather than a guarantee.
Cycles and pregnancies vary
Ovulation does not always occur on a fixed day, and illness, stress, travel, age, breastfeeding and hormonal changes can alter cycles. Estimated fertile windows should not be used as the only method of contraception. Pregnancy dates can also be revised by a clinician using medical history and ultrasound findings.
Use measurements as a starting point
Clothing sizes vary between brands and regions, so fit and comfort matter more than the label. For health concerns, unusual bleeding, severe pain, possible pregnancy or questions about fertility, consult a qualified healthcare professional rather than relying only on a calculator.
Women's Health Tools FAQ
Are these women's health tools free?
Yes. ToolBullet tools are free to use with no account, no download and no sign up required.
Do these tools store my data?
No. ToolBullet tools are designed to run in your browser wherever possible. Inputs are not saved to a ToolBullet account or database.