hCG
calculator.
a calm way to read two blood draws.
If your provider ordered serial beta-hCG tests, you probably have two numbers and a lot of questions. Enter both values and the hours between the draws — this calculator shows your doubling time and how it compares with the typical range. No signup, no email, no ads.
A gentle note before you type: hCG numbers vary enormously between healthy pregnancies, and no calculator can interpret yours. Whatever the result below says, your midwife or doctor is the one who reads it properly — this tool is only here to help you understand the conversation.
hCG levels by week
These are widely published reference ranges for beta-hCG in early pregnancy, measured from the first day of your last period. Notice how wide they are — at five weeks a perfectly healthy pregnancy can sit anywhere between 18 and several thousand mIU/mL.
| weeks from LMP | typical hCG (mIU/mL) |
|---|---|
| non-pregnant | < 5 |
| 3 weeks | 5 – 50 |
| 4 weeks | 5 – 426 |
| 5 weeks | 18 – 7,340 |
| 6 weeks | 1,080 – 56,500 |
| 7 – 8 weeks | 7,650 – 229,000 |
| 9 – 12 weeks | 25,700 – 288,000 |
| 13 – 16 weeks | 13,300 – 254,000 |
Labs vary — always compare your results against your own lab's reference range, printed on the report itself.
what is beta hCG?
Human chorionic gonadotropin — hCG — is the hormone produced by the cells that will become the placenta, starting shortly after the embryo implants. It's the hormone home pregnancy tests detect in urine, and the one a "beta" blood test measures precisely, as a number in mIU/mL. Its job in early pregnancy is to keep the corpus luteum producing progesterone, which maintains the uterine lining until the placenta can take over. Because hCG appears so early and rises so predictably in the first weeks, it's the best window providers have into a pregnancy that's still too small to see clearly on ultrasound — roughly week four to week six.
what doubling time means
A single hCG value tells you surprisingly little, because the normal ranges overlap so much between weeks. What matters is the trend: in a typical early pregnancy, hCG rises exponentially, doubling roughly every two to three days while levels are still low. That's why providers order two tests about 48 hours apart — the ratio between them is far more informative than either number alone.
The doubling time also naturally slows as levels climb. Below about 1,200 mIU/mL, doubling every 48–72 hours is typical. Between 1,200 and 6,000 mIU/mL, 72–96 hours is common. Above 6,000 mIU/mL, doubling can take 96 hours or more — and once levels are that high, an ultrasound usually tells your provider far more than another blood draw. This calculator uses your first value to pick the right comparison window.
when hCG rises slowly
A slower-than-typical rise is one of the most anxiety-inducing results in early pregnancy, so it's worth saying plainly: it is not a verdict. Studies suggest around 15% of pregnancies that go on to be perfectly healthy show a slower hCG rise than the textbook curve, particularly at higher levels. Dating can be off by several days. Labs differ. One draw can simply be an outlier.
At the same time, a slow rise, plateau, or fall is information your provider takes seriously, because it can also accompany an early loss, a vanishing twin, or an ectopic pregnancy. Those are reasons your provider will consider — not conclusions you can draw from numbers at home. The usual next steps are a repeat blood draw in 48 hours, an early ultrasound, or both. If you have one-sided pain, shoulder-tip pain, dizziness, or heavy bleeding, contact your provider or urgent care the same day.
when to stop checking hCG
Sooner than you'd think. Once hCG passes roughly 1,500 – 2,000 mIU/mL, a transvaginal ultrasound can usually see the gestational sac, and from that point the ultrasound — not the blood test — becomes the meaningful check. hCG peaks around weeks 8–10 and then declines to a plateau, so later values stop following any doubling rule at all. Most providers stop serial hCG testing as soon as a healthy pregnancy is confirmed on scan. If you find yourself wanting one more test for reassurance, that's a very human impulse — and a good thing to say out loud to your midwife rather than to a lab requisition form. From here, the gentler way to follow along is week by week: our due date calculator will place you on the timeline.
questions people ask
What is a good hCG doubling time?
In early pregnancy, when hCG is below about 1,200 mIU/mL, levels typically double every 48–72 hours. Between 1,200 and 6,000 mIU/mL the doubling time often slows to 72–96 hours, and above 6,000 mIU/mL it can take 96 hours or more. A "good" doubling time therefore depends on where your levels started — always interpret the number alongside your provider.
Can hCG rise slowly and still be a healthy pregnancy?
Yes. Around 15% of viable pregnancies show a slower-than-typical hCG rise, especially as levels climb higher. A single slow rise is a reason to repeat the test and talk with your midwife or doctor — not a diagnosis on its own.
Do home pregnancy tests show hCG levels?
No. Home urine tests only detect whether hCG is above a threshold (usually around 25 mIU/mL) — they give a yes/no answer, not a number. Line darkness is not a reliable measure of levels. Only a quantitative beta-hCG blood test, ordered by your provider, gives an actual value you can track.
When does hCG peak in pregnancy?
hCG typically peaks around weeks 8–10 of pregnancy, then gradually declines and settles at a lower plateau for the rest of pregnancy. This is why doubling time only matters in the first weeks — a falling hCG after week 10 is usually normal.
Does a high hCG level mean twins?
Not necessarily. Twin pregnancies do tend to produce higher hCG, but the normal ranges are so wide that a single high value cannot confirm twins. Only an ultrasound can. If your numbers are on the high side, it may simply mean your dates are a little further along than you thought.
This calculator and the ranges above are for general guidance only and are not a diagnosis or a replacement for medical assessment. If any result worries you, call your midwife or doctor — that's always the right move, never an overreaction.