Free Online Calculators

DayCalc.io provides free, accurate calculators for life's most important moments — from family planning to professional exams. All calculators run entirely in your browser, with no signup, no tracking, and no data sent to a server.

Available Calculators

• Fertility & Conception Window Tracker — Calculate your fertile window, ovulation day, and optimal conception dates with a colour-coded calendar view.
• Pregnancy Due Date Calculator — Estimate your due date using Naegele's Rule. Track your trimester, current week, and 15 key milestones.
• CPA · Bar · USMLE Exam Prep Calculator — Track your exam countdown, calculate daily study hours, and find your score release date.