1. Your EDD is the reference point
We count how many days your selected day falls before or after your EDD. Your EDD places the curve on the calendar.
Could labour start today?
Enter your due date to place the reference on your calendar.
Trage deinen ET ein.
Offset
Calendar position relative to the EDD.
EDD
Estimated chance
If labour has not started by the beginning of this day, what is the chance that it starts during this day?
The reference group includes only labours that eventually started on their own. Induced labours and caesareans before labour are not included.
– %
Statistical estimate only: not a personal medical assessment, medical advice or a guarantee. It cannot tell you when your own labour will start.
Based on NICE / NHS England 2019–20. Daily estimates are calculated by spreading each published weekly share evenly across seven days—not from measured daily data.
Two more ways to look at this day
Share starting on this day
Of all labours in the reference group, the estimated share that starts on this day—not just those still waiting.
– %
Share started by this day
Of all labours in the reference group, the estimated share that has started by the end of this day.
– %
Source and calculation
Your due date maps the reference to calendar dates. It does not change the distribution.
Optional: adjust model and region
The model describes a statistical group, not an individual prediction.
Die Region dient nur als grobe Modellvariante.
Your calculator inputs stay on your device. We count received Free/Pro calculation signals without inputs, and page/country totals, for up to 90 days. Country lookup briefly uses your IP locally; no IPs or visitor identifiers are saved in these statistics.
Explore the timeline and figures
Daily value details
All figures refer to the same selected reference group, not your personal risk.
Base data – distribution bars
Uniformly interpolated daily shares (EDD−21 to EDD+13)
NICE weekly data · daily interpolation
Quelle: –
Who will guess it right?
A name or a birthday: invite your favourite people to guess. You choose when to reveal the surprise.
Something light: calendar stories (optional)
Frequently asked questions about due dates
How accurate is an estimated due date?
The weekly shares describe a historical group in England, not an individual prediction. Daily values use uniform interpolation; their accuracy has not been validated against individual trajectories.
What does “daily probability” mean?
The main percentage is the model's chance of labour starting on the selected day, provided it had not started before that day. It only describes the group whose labour eventually started on its own, not your personal chance. Daily values are calculated from weekly data.
Does this predict labour onset or the baby's birth?
The reference describes spontaneous labour onset, not the birthday or a separately predicted rupture of membranes. Induction and caesarean are not part of the reference group.
Does Pro simply make the free figure more accurate?
Pro uses a separate model: age, early BMI, previous spontaneous labour onset and conception method can change the estimate. If previous onset timings are unknown, a prior vaginal birth can contribute instead. The model combines study findings with unvalidated assumptions; greater accuracy has not been established. The free calculator stays unchanged, based on the NICE reference.
Why is a Pro estimate sometimes unavailable?
Pro displays model values from 39+0 to 41+6 weeks, only after pregnancy and care details are confirmed. Missing optional factors have no numerical effect; missing required details, planned interventions or certain medical histories block the display. Any missing information is explained.
Are the Pro preview figures already my personal values?
No. The preview uses the same calculation as Babyforecast Pro, but with a clearly labelled fictional profile. Only your EDD and selected day are reused from the free calculator. The sample factors change the model values but are not your details. Without an EDD, example dates are used.
Is my EDD or any other input stored?
The calculation runs in your browser. Pro and sharing links put the EDD after #, outside the server request. Anyone receiving the full link can still read it. History and bookmarks may retain it. See Privacy in the footer for details and removal options.
Can I use the result for medical decisions?
No. Babyforecast is statistical orientation and does not replace advice from your doctor or midwife.
Sources, calculations and useful terms
Due-date probability, explained clearly
Babyforecast shows why an EDD is a window rather than a promise tied to one exact day.
- Published weekly shares with explicit daily interpolation.
- Conditional reference share, daily share, and cumulative share are explained separately – not a personal prediction.
- Your calculator inputs stay on your device. We count received Free/Pro calculation signals without inputs, and page/country totals, for up to 90 days. Country lookup briefly uses your IP locally; no IPs or visitor identifiers are saved in these statistics.
How the three figures are calculated
Ratgeber: Wie genau ist der ET? (Deutsch) · Due-date guide (English)
These figures come from NICE NG207 (NHS England 2019–20) and describe only labours that eventually started spontaneously, not all pregnancies still ongoing today. The source reports weekly shares, which we spread equally across seven days for the chart – not measured daily values or a personal prediction.
2. Published, not manually adjusted
NICE publishes weekly shares. We normalise the rounded total of 99.9% to 100% and spread each term week equally across its seven days. There is no country or parity correction.
3. Pro includes personal factors
Babyforecast Pro uses a separate, study-informed model estimate. Available factors change the model curve; the free calculator remains the unpersonalized NICE reference. The combined formula is not clinically validated: no personal medical assessment and no guarantee.
An arithmetic example within the reference group
Fictional, for explanation only: of 100 labours that eventually start spontaneously, 50 start before the selected day and 5 on that day. Induced labours are not part of this group.
Daily probability
10 %5 divided by the 50 outstanding onsets gives 10%. This conditions only within the selected group, not on all pregnancies still ongoing today.
Daily share
5 %Cumulative share
55 %50 + 5 out of 100 have started by the end of this day.
Induction and caesarean can preclude spontaneous onset. These competing events are not predicted here. Not a basis for medical decisions.
Glossary of key terms
Brief explanations of the key medical and statistical terms used here.
More about the model and its limits
Brief context on data, modeling choices, and limits.
Share your due date or give feedback
Feedback
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Legal information and privacy
Notices, sources & liability
Copyright © 2026. All rights reserved. Provide attribution before sharing.
Model & background sources:
- Datenquelle: NICE NG207, Tabelle 1 · NHS HES/MSDS 2019–20.
- WHO recommendations on due-date estimation, guideline "Antenatal care for a positive pregnancy experience", 2016.
- These figures come from NICE NG207 (NHS England 2019–20) and describe only labours that eventually started spontaneously, not all pregnancies still ongoing today. The source reports weekly shares, which we spread equally across seven days for the chart – not measured daily values or a personal prediction.
Legal & medical disclaimer (per Sec. 675 (2) German Civil Code): This calculator is a purely statistical simulation for informational purposes. It does not replace medical examinations, advice, or diagnosis. No guarantee is given for correctness, completeness, or timeliness. Medical decisions must be made together with your care team.
Data protection (GDPR):
- The free calculation is processed entirely in your browser. The current Pro prototype neither transmits nor stores profile data; a future service may do so only after sign-in, entitlement verification, and explicit consent.
- A personal estimate automatically evaluates your details but does not make medical or legally significant decisions. Reloading does not erase saved games, history or shared links. See Privacy in the footer for removal options.
- All images, fonts, and scripts required by the calculator are served directly by this website; no third-party CDNs are embedded.
Your calculator inputs stay on your device. We count received Free/Pro calculation signals without inputs, and page/country totals, for up to 90 days. Country lookup briefly uses your IP locally; no IPs or visitor identifiers are saved in these statistics.
Contact & responsibility:
Controller: Wolf Wittmund, Immenhoferstraße 83, 70180 Stuttgart, Germany. Privacy contact: wolfwittmund@googlemail.com. Never post personal information in public GitHub issues. See Privacy in the footer for the full notice and local data controls.