Got a single beta-hCG result and wondering how many weeks pregnant you might be? Enter your value to see the most likely gestational-age window, plus a full table of typical hCG ranges by week.
| Gestational age (weeks) | Typical beta-hCG range (mIU/mL) |
|---|
What this tool does
- Accepts a single quantitative beta-hCG value (mIU/mL). Note: 1 IU/L = 1 mIU/mL numerically.
- Compares your value to broad, commonly cited early-pregnancy reference bands (e.g., 3 w, 4 w, 5 w…).
- Highlights the closest gestational-age band and shows the full reference table for context.
How the “closest week” is chosen
- Each row has a lower and upper bound (min–max). The tool first checks if your value falls inside any band.
- If inside multiple overlapping bands, it prefers the one where the value is nearest that band’s midpoint (a small “inside” preference is applied).
- If not inside any band, it chooses the band with the smallest absolute distance to your value (distance to the nearest edge).
- This selection logic is implemented with simple comparisons and normalized distance; there are no logical
&&or||operators in the script.
Reference bands used
- Bands cover ~3 to ~40 weeks and intentionally overlap (physiologic variation and assay differences are large).
- Values are illustrative (e.g., 5–50 at ~3 w; 18–7,340 at ~5 w; 1,080–56,500 at ~6 w; higher plateaus around 7–12 w, then gradual decline).
- Because laboratories differ, a user’s report may cite slightly different intervals. The tool treats bands as approximate guides, not strict cut-points.
Scope and limits
- A single beta-hCG cannot precisely date a pregnancy. Ultrasound is the standard for dating once structures are visible.
- hCG varies widely between pregnancies and assays; multiple gestations often have higher absolute values but overlapping ranges.
- Serial trends (repeat testing 48–72 hours apart) are more informative for early viability than a single value.
- Results are for education only and do not constitute medical advice. Always interpret with clinical context and local lab reference ranges.
Last updated: 17 Oct 2025
How to use this calculator
- Enter your beta-hCG value: type your lab number in mIU/mL. (If your lab shows IU/L, it’s the same number.)
- Submit: we compare your value to typical ranges and highlight the most likely gestational-age week band.
- Read the label: you’ll see whether your value is Within, Below, or Above the typical range for that week window.
- Next step: use the Gestational Age or Due Date calculators for date-based accuracy, and confirm timing with ultrasound when appropriate.
How to read the table
- Week bands overlap: a single hCG cannot pinpoint exact weeks. It suggests a likely window only.
- Within/Below/Above: the label reflects where your value falls relative to the typical range for the highlighted band.
- Multiples: higher absolute hCG values are common in twins/triplets, but values alone can’t diagnose multiples.
Educational tool only. Ultrasound provides definitive dating and assessment—follow your clinician’s plan.
Last updated: October 2025
hCG week-estimate: FAQs
Can a single hCG tell me exactly how many weeks?
No. Ranges are broad and overlap between weeks. A single value suggests a likely window. For precise dating, use LMP/EDD methods or ultrasound.
What units should I use?
mIU/mL and IU/L are numerically equivalent for this test. Enter the number as shown on your result.
My value is “Above” the typical range—does that mean twins?
Not necessarily. Multiples can have higher absolute levels, but hCG alone can’t diagnose twins. Ultrasound confirms multiples. If you’re tracking rise, try the Doubling Time or the Twins/Triplets Doubling Time tools.
Why doesn’t this match my ultrasound date?
Biology varies—ovulation timing, implantation, and lab differences matter. Ultrasound (especially early CRL dating) is the reference standard for gestational age.
What if my result seems very low?
Early results can be low and still normal. Repeat in 48–72 hours to see the trend, or use our Doubling Time (with Chart) calculator.
How does IVF/FET affect interpretation?
Transfer timing provides excellent dating. Use our IVF/FET Due Date or FET Date tools, then compare any hCG draws to the appropriate week window.