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Every calculator in one place, free and with no sign-up. Results show instantly — we don't hide them behind a form. Each one explains what the number means, where the reference ranges come from, and what it cannot tell you.
A calculator sees three or four figures. A specialist sees your history, your scans, your partner's results, and how you actually responded to treatment. If you're between cycles, changing clinics, or something in your results doesn't add up, a second opinion is the fastest way to find out whether anything would be done differently.
Free first consultation. No obligation to start treatment, and it doesn't affect your care at your current clinic.
These tools provide general information and are not a diagnosis or a substitute for assessment by a qualified clinician. Reference ranges and sources are stated on each calculator. Predictive estimates describe groups of people and cannot predict an individual outcome.
A calculator sees three or four figures. A specialist sees your history, your scans, your partner's results, and how you actually responded to treatment. If you're between cycles, changing clinics, or something in your results doesn't add up, a second opinion is the fastest way to find out whether anything would be done differently.
Free first consultation. No obligation to start treatment, and it doesn't affect your care at your current clinic.
What your trigger type and timing mean, and what to ask.
InterpretationExplains a result or decision you already have. It recommends nothing.
Reads back the trigger your clinic has planned or given, against the pattern normally used. It does not tell you when to trigger — that is decided on the day from follicle measurements this form cannot see.
Source — Interpretation only. Trigger timing is decided on the day from ultrasound follicle measurements and hormone levels — no form can supply those. Typical practice is to trigger when lead follicles reach roughly 17 to 20mm, read alongside oestradiol and the number of follicles developing. A GnRH agonist trigger with a freeze-all is the most effective prevention of severe OHSS in high responders.
The bands on this page are drawn from published sources but have not yet been reviewed by our medical team, and some vary by laboratory or assay. Check against the reference range printed on your own report.
From your instructions
Largest follicle at your last scan
0 if not measured
That falls in the 17 to 20mm band.
Your result of 18 mm lead follicle sits in the highlighted band. Bands are reference points used alongside clinical findings — not a diagnosis.
The range most units trigger in. The lead follicles are mature and the cohort behind them has usually caught up.
Interpretation only. Trigger timing is decided on the day from ultrasound follicle measurements and hormone levels — no form can supply those. Typical practice is to trigger when lead follicles reach roughly 17 to 20mm, read alongside oestradiol and the number of follicles developing. A GnRH agonist trigger with a freeze-all is the most effective prevention of severe OHSS in high responders.
These tools apply across the process rather than at one point in it.
Because it depends on how your follicles grow, which is measured by ultrasound during the cycle. The trigger completes egg maturation and fixes collection about 36 hours later, so it is set on the day rather than at the start.
hCG is the traditional choice and sustains the hormonal stimulus for days, which drives OHSS in high responders. A GnRH agonist trigger clears far faster and substantially reduces severe OHSS, which is why it is usually paired with freezing all embryos rather than a fresh transfer.
Yes. At 19 or more follicles of 11mm or larger, OHSS risk is recognised as raised. Ask whether an agonist trigger and a freeze-all are being considered, and make sure you have a number to call after collection.
Call your clinic immediately rather than waiting. Timing determines when eggs are collected and whether they are mature, so they need to know in order to adjust.
What follicle sizes are you waiting for? Will I have hCG or an agonist trigger, and why that one for me? If I am a high responder, would you switch and freeze all embryos?
A calculator sees three or four figures. A specialist sees your history, your scans, your partner's results, and how you actually responded to treatment. If you're between cycles, changing clinics, or something in your results doesn't add up, a second opinion is the fastest way to find out whether anything would be done differently.
Free first consultation. No obligation to start treatment, and it doesn't affect your care at your current clinic.
This explains a plan you have already been given. Take the trigger at exactly the time your clinic specified — set an alarm for it. Nothing here is a diagnosis or a substitute for assessment by a clinician.
A calculator gives you a number. These explain what it means, and what it does not.
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