Trying & Testing Timeline
Start with the cycle or timing record you actually have. One interaction shows every supported ovulation, fertile-window, expected-period, and home pregnancy-test timing reference that record can provide.
Calendar-estimated ovulation is not confirmed ovulation, and a pregnancy-test date or window is a timing reference—not pregnancy probability, diagnosis, or a guaranteed result.
Pregnancy calculators with an optional browser-local Pregnancy Record for continuity, reuse, and history.
One record, only the outputs it can support
| Record you have | Supported outputs | What is not inferred |
|---|---|---|
| LMP + usual cycle | Estimated fertile window, ovulation, expected period, test reference, today context | Confirmed ovulation or pregnancy probability |
| Expected period | Home-test reference and early-negative context | Ovulation, conception, or implantation |
| Well-supported ovulation | General 12–15 DPO urine-hCG reference window | Conception date or hCG concentration |
| Current DPO | Derived calendar reference and testing window | Ovulation confirmation or individual probability |
| Recent relevant sex date | Conservative 21-day test reference | Conception, implantation, or contraception effectiveness |
How to read the provenance labels
- USER-ENTERED identifies the record or number you supplied.
- DERIVED identifies direct date arithmetic from that record.
- APPROXIMATE identifies a calendar estimate that can differ from an individual biological event.
The labels prevent a cycle estimate, an entered record, and a biological event from being presented with the same certainty.
Important interpretation limits
- Testing before the applicable reference timing can produce an early negative because urine hCG may not yet be detectable. A missing control indicator means the test is invalid, not negative.
- A cycle model, LH/OPK result, cervical mucus, and basal-temperature shift provide different kinds of context; none makes this calendar result confirmation of exact ovulation or a fertility score.
- Fertility medicines containing hCG and residual hCG after a recent pregnancy can affect test interpretation. Follow the testing schedule from the fertility clinic when treatment applies.
- The dates are not proof of safe or unsafe days for contraception and do not calculate individual pregnancy probability. This tool does not determine emergency-contraception eligibility, product, or dose.
- A positive result does not establish pregnancy location, viability, gestational age, or a due date.
For the evidence behind fertile windows, LH/OPK, cervical mucus, basal body temperature, hCG, early negatives, recent-sex timing, treatment hCG, and recent pregnancy, read the Trying, Ovulation and Pregnancy Test Timing Guide.
Official sources
Each source is mapped to the specific timing or boundary statement it supports. These sources do not review, sponsor, or endorse Pregnancy Metrics.
- ASRM — Optimizing Natural Fertility
Supports the six-day fertile-window definition, higher-fertility timing near ovulation, cycle variability, and the limits of calendar and app predictions.
- ACOG — Trying to Get Pregnant? Here’s When to Have Sex
Supports cycle day 1, the cycle-length-minus-14 calendar convention, and plain-language cycle timing context.
- ACOG — Fertility Awareness-Based Methods
Supports the distinction between fertility-awareness information and contraception and explains that fertile timing cannot be reduced to guaranteed safe days.
- NHS — Doing a pregnancy test
Supports testing from the first day of a missed period and the 21-day fallback after unprotected sex when the next-period date is unknown.
- Office on Women’s Health — Pregnancy tests
Supports hCG detection, instruction and control-indicator requirements, and why early testing can produce a negative result.
- FDA — Home-use pregnancy tests
Supports variation in home-test sensitivity and use, false-negative risk from early testing, and the general urine-hCG timing context after ovulation.
- MedlinePlus — Ovulation home test
Supports that an LH surge may precede ovulation while a positive home test does not make the exact ovulation date certain.
- CDC — How to be reasonably certain a patient is not pregnant
Supports limits of urine testing after recent sex or a recent pregnancy and the possibility of residual hCG.
Private by default and limited in scope
Inputs remain in ephemeral browser state. They are not placed in the URL or hash, sent to an API or server, or stored in localStorage, sessionStorage, an account, or a database. Reloading starts a new blank interaction.