Period Calculator Online – Predict & Track Your Menstrual Cycle Free

Spluxly’s free online Period Calculator helps women accurately predict upcoming period dates, ovulation timing, and fertile windows — all in one easy-to-use tool. By entering your last menstrual period (LMP), average cycle length, cycle regularity, and the number of cycles you want to forecast (up to 6), the calculator instantly maps out your complete menstrual cycle schedule. It predicts ovulation 14 days before your next period and identifies your full fertile window — 5 days before to 1 day after ovulation — with automatic ±2-day adjustments for irregular cycles. A detailed event table and a color-coded first-cycle timeline chart make it effortless to understand and plan around your cycle. Whether you’re managing your reproductive health, planning a pregnancy, or simply staying prepared, this tool has you covered. Completely free, no registration required.

How to Use the Period Calculator Online

Predicting your upcoming periods is quick and straightforward. Follow these simple steps:

• Enter Last Menstrual Period (LMP) – Select the first day of your most recent period (e.g., 2026-05-01)
• Enter Cycle Length – Input your average cycle duration in days (e.g., 28; range 21–35)
• Select Cycle Regularity – Choose Regular (±2 days) or Irregular (>±2 days)
• Choose Cycles to Predict – Select how many future cycles to forecast (1–6)
• Click Calculate – Instantly view upcoming period dates, ovulation date, fertile window, a full event table, and a color-coded first-cycle timeline chart

Why Use Spluxly’s Period Calculator?

• Multi-Cycle Forecasting – Predicts up to 6 future period start dates in a single calculation for long-term cycle planning
• Ovulation & Fertile Window – Pinpoints ovulation and the full 6-day fertile window for the first predicted cycle
• Comprehensive Event Table – Displays all key cycle dates including LMP, fertile window start and end, ovulation, and upcoming period dates in one clear view
• Color-Coded Timeline Chart – Visually maps the first cycle with fertile days in pink and ovulation marked in blue for instant clarity
• Irregular Cycle Support – Automatically extends ovulation and fertile window estimates by ±2 days for women with irregular cycles
• 100% Free & Instant – No registration, no fees — complete menstrual cycle predictions delivered in seconds