Enter the egg provider’s starting age to estimate the average number of future singleton-equivalent live births across the remaining modeled reproductive span. The results also show the chance of different family sizes and a modeled age-window summary.
Modeled average from your starting age
Average future singleton-equivalent live births
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Chance of at least – children
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Chance of fewer than – children
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Middle range (25th to 75th percentiles)
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Average under sensitivity scenarios
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Changes one population-rate assumption around the base estimate.
Full modeled family-size distribution
Each row is the chance of exactly that many future singleton-equivalent live births. A row supported by fewer than 32 of 8,192 paths is shown only as <0.4% because a more precise percentage is not stable.
Modeled age window
- Starting age
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- Post-birth wait
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Assumptions and limitations
- The model assumes natural conception with the egg provider’s own eggs, no known infertility, and no previous time trying.
- Each successful pregnancy contributes one singleton-equivalent live birth; multiples are not modeled separately.
- The model assumes continuous attempts after the selected wait and does not include intended stopping, treatment, breastfeeding-related suppression, postpartum recovery, parity effects, or secondary infertility.
- The permanent-sterility endpoint is not menopause, a medical cutoff, or a personal prediction.
This educational population estimate is not a fertility test or an individual forecast.
Methodology
The calculator follows a fixed simulated cohort from the selected starting age until each path's modeled reproductive endpoint. Conception chance declines with age; a conception may end in pregnancy loss or a singleton-equivalent live birth. Attempts pause after each birth for the selected number of months.
Conception chance declines with age in this model. Numbered birth ages are not shown because the people who reach later births form progressively smaller selected groups, so those averages do not form one representative schedule. The age-window summary keeps the starting age, the delivery deadline when applicable, and the modeled reproductive endpoint.
Results through three births are calibrated to published natural-conception family-completion benchmarks. Fourth and later births use an unvalidated continuous-trying tail extension; the result reports how much that tail adds to the mean. Headline groups are exact complements shown to one decimal. Percentages supported by fewer than 32 of 8,192 paths are suppressed below the 0.4% support floor. The discrete 25th-to-75th-percentile range reports its actual included share.
Primary sources
Frequently asked questions
What does the average number of children mean?
It is the model-population average number of live-born children delivered after attempts begin at the selected starting age. It is not a personal maximum or prediction.
Does the estimate include children born before the starting age?
No. The calculation begins at the age you enter and counts modeled live births after that point.
Why does the age window not list average birth ages?
Conception chance declines with age in the model. The people who reach later births form progressively smaller selected groups, so their separate average ages do not form one representative birth schedule. The summary instead shows the starting age, the delivery deadline when applicable, and the modeled reproductive endpoint.
Is the modeled infertility age the same as menopause?
No. It is a reproductive endpoint used by the population model, not a personal menopause date or medical cutoff.
Does the calculator include IVF, donor eggs, or known infertility?
No. It models natural conception using the egg provider's own eggs. Treatment, donor eggs, individual diagnoses, previous time trying, and unplanned pauses can produce different outcomes.
Medical note: This calculator is an educational population estimate, not a fertility test or individual forecast. If you have a known fertility concern, irregular or absent cycles, recurrent pregnancy loss, or prior time trying, ask a qualified clinician about advice that reflects your history. See the medical disclaimer.