Use this tool to interpret antral follicle count by age. It gives an age-adjusted percentile, a plain-language meaning, and suggested re-test timing.
How to use this calculator
- Enter your age and your antral follicle count from ultrasound.
- Optional: add cycle day, hormonal contraception, and whether you have a PCOS diagnosis.
- Read your age-adjusted percentile and a short interpretation.
- Read what AFC can and cannot suggest about ovarian-stimulation response and repeat testing.
Educational only, not medical advice. Discuss results with your clinician, especially if planning IVF or egg freezing.
Methodology & sources
How the percentile is estimated
Your age and total AFC are compared with the age-specific reference model published by La Marca and colleagues in 2011. The study analysed 362 women recruited at a university hospital in Modena, Italy, with regular 25–35-day cycles and both ovaries. It counted all 2–10 mm follicles in both ovaries during the follicular phase.
The calculator uses the paper's CG-LMS equation with its published age-specific median (M), L = 0.425 and S = 0.490: z = ((AFC / M)^0.425 − 1) / (0.425 × 0.490). The standard-deviation score is converted to an estimated percentile. Because AFC is a whole-number count and the published medians are rounded to one decimal place, the result says “about.” Counts outside the paper's published 5th–95th values are shown only as below 5th or above 95th.
Reference limits
The study excluded infertility, hormone use in the previous six months, ovarian surgery, pelvic inflammatory disease, and chronic, metabolic or endocrine disease including hyperandrogenism. Age explained 37% of AFC variation. This is a cross-sectional study comparison, not a diagnosis or a population-wide standard, and it may not fit PCOS or these other situations.
The reference scans were performed in the follicular phase, and ASRM defines AFC using an early-follicular scan. Long-term combined hormonal contraception can temporarily lower AFC in some people. A scan of one ovary cannot be compared directly with a total for both ovaries.
What AFC can and cannot predict
AFC can help predict quantitative response and oocyte yield after ovarian stimulation, but this calculator cannot predict an exact egg count. AFC is a poor independent predictor of egg quality, natural pregnancy or live birth. There is no universal AFC repeat interval; repeat testing should be tied to a clinical decision.
- La Marca et al., 2011 — the CG-LMS age-specific AFC reference model used by this calculator.
- ASRM Committee Opinion, 2020 — AFC measurement, treatment-response value and limits for fertility prediction.
- ASRM Committee Opinion, 2024 — interpretation after long-term hormonal contraception.
- 2023 International Evidence-based PCOS Guideline — PCOS and follicle-count context.
Frequently asked questions
What is antral follicle count (AFC)?
AFC is the number of small resting follicles seen on ultrasound, often measured early in the cycle. It is one snapshot of ovarian reserve.
Which cycle day is best for AFC?
Many clinics measure AFC in the early follicular phase. If your scan was on a different day, interpretation can vary and repeat measurement may be suggested.
Do contraception or PCOS change AFC?
Combined hormonal contraception can temporarily lower AFC in some people, while PCOS can raise follicle counts. The study reference may not fit either situation, so interpret the result with your clinician.
How often should I re-test?
There is no universal AFC repeat interval. Repeat it when your clinician says another scan would change treatment or planning.
Does AFC predict natural fertility?
AFC is more useful for treatment planning, such as expected response to ovarian stimulation. It does not predict the exact time to pregnancy on its own.
How does AFC compare with AMH?
AFC and AMH both reflect ovarian reserve and can disagree. Using both does not consistently improve prediction, so each result needs clinical context.