出産予定日計算機
妊娠の出産予定日と妊娠期間を計算します。
出産予定日
赤ちゃんの出産予定日を予測
この計算機はネーゲレの法則を使用し、最終月経の初日に280日(40週)を加算します。医療従事者が使用する標準的な方法です。
おすすめのツール
役に立つかもしれない厳選されたツール
Estimating Your Pregnancy Due Date
概要
A due date estimates when a baby is likely to arrive, typically about 40 weeks from the first day of the last menstrual period. This calculator gives that estimate instantly from your last period date. It is a guide — only a small share of babies arrive exactly on the due date.
使い方（ステップ）
- 1
Enter your last period date
Use the first day of your last menstrual period.
- 2
Adjust cycle length if needed
The default assumes a 28-day cycle.
- 3
Read the estimated due date
It also shows roughly how many weeks along you are.
仕組み
The most common method (Naegele's rule) adds 280 days (40 weeks) to the first day of your last menstrual period, assuming a regular 28-day cycle. The tool can adjust for cycle length. Because conception timing varies, the result is an estimated date, with normal full-term delivery occurring anywhere from 37 to 42 weeks. A healthcare provider can refine it with an ultrasound.
こんなときに使う
Getting an early estimate of when your baby may arrive. Tracking how many weeks along you are. Planning appointments and leave around an expected date.
よくある質問
It is an estimate. Only about 1 in 20 babies arrive on the exact due date; most come within a couple of weeks either side.
注意事項
Due-date estimates are approximate and for informational purposes only — they are not medical advice. Only a qualified healthcare provider can confirm your due date and monitor your pregnancy.