Pregnancy Due-Date Calculator
Estimate your due date from your last menstrual period (Naegele's rule: LMP + 280 days).
For general guidance only — not medical advice.
About this tool
Pregnancy Due-Date Calculator is a free calculator on PureHealthness. Estimate your due date from your last menstrual period (Naegele's rule: LMP + 280 days). It runs entirely in your browser: nothing you type is sent to a server, no account is required, and the result appears the moment you press calculate. Because it works offline once the page has loaded, you can use it on a phone at the gym, in a clinic waiting room, or anywhere else without a signal.
How to use it
- Enter your numbers in the fields above — use the units shown next to each field (metric or imperial, per the labels).
- Press Calculate. The main figure appears in the large box, with a short interpretation underneath.
- Change one value at a time and press calculate again — that is the quickest way to see what actually moves your result.
- Write the number down or screenshot it before you close the tab; nothing is stored for you afterwards.
What it can and cannot tell you
A calculator gives you an estimate built from standard formulas. It cannot see your medical history, your medication, your injuries, your pregnancy, your age-related exceptions, or how you actually feel on the day. Use the number as one input among several — a starting point for a conversation, not a verdict. If a result surprises you, or if you are managing a health condition, take it to a qualified professional rather than acting on it alone.
We do not store your inputs, and we do not require an email address to use the tool. If you find a result you think is wrong, tell us — corrections make the whole library better.
Common questions
Is Pregnancy Due-Date Calculator free? Yes — every calculator and guide on PureHealthness is free, with no sign-up and no paywall.
Does it work on a phone? Yes. The layout adapts to small screens, and the maths runs locally in your browser.
Is my data saved anywhere? No. Your inputs stay in the page, in your browser, and disappear when you close the tab.
Can I use this instead of seeing a doctor? No. It is an educational estimate. For diagnosis, treatment or anything urgent, speak to a healthcare professional.