Pregnancy Trimester
Find the current pregnancy trimester, stage and months remaining.
About Pregnancy Trimester
Gestational age is mapped to its trimester (roughly 13-week blocks), the weeks left until 40 are counted, and the pregnancy month is derived. Trimesters gate which tests, scans and symptoms are typical, so identifying the stage supports timely prenatal planning.
Formula
Pregnancy Trimester
Trimester: 1-13, 14-27, 28-40 weeks; month = weeks / 4.345
- gestational age
- Weeks since the start of the pregnancy
Worked example
With the default values below, Pregnancy Trimester returns Trimester of 2. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Gestational ageaccepts 1–42 wks
- 20 wks
Results
- Trimester
- 2
- Stage
- Second trimester
- Weeks to Go
- 20 wks
- Month of Pregnancy
- 5.0
Step by step
- 1Values used
- 2Pregnancy Trimester
- 3Trimester= 2
- 4Stage= Second trimester
- 5Weeks to Go= 20 wks
- 6Month of Pregnancy= 5.0
Assumptions and limits
- The result is derived only from the single input listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 1 decimal place, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
How is Pregnancy Trimester calculated?
Trimester: 1-13, 14-27, 28-40 weeks; month = weeks / 4.345 Gestational age is mapped to its trimester (roughly 13-week blocks), the weeks left until 40 are counted, and the pregnancy month is derived.
Why does Pregnancy Trimester matter?
Trimesters gate which tests, scans and symptoms are typical, so identifying the stage supports timely prenatal planning.
What values do I need to enter?
This calculator takes 1 input: Gestational age. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.