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FREE ONLINE TOOL

Free Ovulation
Calculator

Free advanced Ovulation Calculator with calendar estimates, cycle-history variability, LH-surge timing, known-ovulation mode, fertile-window bands, peak-fertility dates, cycle-day lookup, multi-cycle forecast, and transparent uncertainty.

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FreeUse this tool without paying.No sign upStart with the tool right away.Clear stepsRead the tool’s own guidance.

About Free Ovulation Calculator

Use a single cycle, multiple historical cycle lengths, a detected LH surge, or a known ovulation date. The calculator separates a calendar estimate from biological signals, shows uncertainty explicitly, and never presents one predicted day as guaranteed.

Workspace options

  • First day of current period
  • Usual cycle length · days
  • Ovulation offset before next period · days
  • Recent cycle lengths · days
  • First positive / surge detected
  • Expected next-period offset · days

Available actions

  • Single cycle
  • Cycle history
  • LH surge
  • Known ovulation
  • Copy fertility report
  • Export CSV