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Egg freezing timing calculator

When is the right time to freeze?

Q: So what is the best age to freeze?

There isn't one, and any tool naming a single age is not being straight with you. Egg quality falls with age while the probability you actually use them rises. Published usage rates peak in the 36–39 band.

Q: Is freezing wasted if I never use them?

Most people who freeze do not use their eggs, usually because they conceived without needing to. That is not a failure — but it should be a decision made knowingly rather than discovered later.

Q: Why is the return rate lower for the youngest group?

Because they had more time to conceive naturally. The 36–39 band returns most often, which is consistent with freezing closer to the point of need.

The trade nobody names: freezing earlier gets better eggs but raises the chance you never need them.

Age you would freeze at

years

These are example numbers. Replace them with yours, then press Calculate.

Example answer

21% chance of use

15–35%

A middle position. Eggs are still good and the chance of using them is meaningful.

This is a guide, not a diagnosis. Share the result with your doctor.

Your result on the scale

The ranges this calculator uses. Yours is highlighted.

Your numbers

Everything worked out from what you entered.

Eggs per cycle at this age: 12
Chance you use them: 21%
Chance you never need them: 79%
Cycles to bank 20: 2

What each result means

Your result is highlighted. Your own clinic's advice always comes first.

Your result<15%

Freezing this early gets the best eggs available to you, and carries the highest chance the money is spent on eggs you never need — usually because you conceive without them.

Your result15–35%

A middle position. Eggs are still good and the chance of using them is meaningful.

Your result35%+

You are much more likely to use what you bank, but each cycle returns fewer eggs, so reaching a useful number costs more.

Where this fits in your journey

The usual order, from trying to conceive to pregnancy. Not everyone needs every stage. This calculator belongs to stage 3.

Stage 3 · you are here

Planning IVF

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Egg freezing

This calculator: When is the right time to freeze?

Calculators for what comes next

How this is worked out

Population estimateAn average for people with your inputs, not a prediction for you. Individual outcomes vary widely around it.

Most people who freeze eggs never use them. Published usage rates range from about 8% to 16% of women returning to thaw, and one cohort found return rates of 10.6%, 26.6% and 12.7% for women who froze at 35 or under, 36–39, and 40 or over respectively.

About this calculator

?What it tells you

Freezing now versus later. The trade nobody names: freezing earlier gets better eggs but raises the chance you never need them.

✓When to use it

While deciding whether to freeze now or later

iWhat you need

Age you would freeze at (years)

!What it cannot tell you

There is deliberately no recommended age here. The two curves run in opposite directions and where you sit between them is a personal judgement, not a clinical one.

Common questions

So what is the best age to freeze?

There isn't one, and any tool naming a single age is not being straight with you. Egg quality falls with age while the probability you actually use them rises. Published usage rates peak in the 36–39 band.

Is freezing wasted if I never use them?

Most people who freeze do not use their eggs, usually because they conceived without needing to. That is not a failure — but it should be a decision made knowingly rather than discovered later.

Why is the return rate lower for the youngest group?

Because they had more time to conceive naturally. The 36–39 band returns most often, which is consistent with freezing closer to the point of need.

Sources

Usage rate 8.4% (54/645) over a cohort followed to 2020; 16% in a separate cohort with mean freeze age 37.1. Return-to-thaw by age at freezing: 10.6% (≤35), 26.6% (36–39), 12.7% (≥40). Live birth by age at freezing from Hirsch et al. 2024.

Hirsch et al., Human Reproduction Update (2024)

In an emergency

If you have any of the warning signs listed here, don't wait for a test result or a calculator. Get help now.

112All emergencies, anywhere in India 108Ambulance

Also call your IVF clinic. Most clinics give an emergency number on your treatment or discharge sheet. Save it in your phone now, before you need it.