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LH Ratio Calculator

Calculate your LH ratio from ovulation test strips

Compare the intensity of your test line to the control line to determine if you're experiencing an LH surge.

How dark/intense is the test line? 0 = invisible, 100 = very dark
How dark/intense is the control line? Usually 100 (fully visible)

Understanding LH Ratios

Ratio Status Meaning
0.00 - 0.39 Low LH levels are low. You're not in your fertile window yet. Keep testing daily.
0.40 - 0.79 High LH levels are rising. Your fertile window is approaching. Test more frequently (2x per day).
0.80+ Peak LH surge detected! Ovulation will likely occur within 24-36 hours. This is your peak fertility window.

Tips for Accurate Results

  • Test at the same time each day (between 10am-8pm is best)
  • Limit fluids 2 hours before testing
  • Compare test line to control line on the same test strip
  • Use the same brand of tests for consistency
  • Test daily until you detect your surge
Analyze Test with AI View Test Gallery
⚠️ Medical Disclaimer

This tool is not a medical diagnosis. The calculations provided are for informational purposes only and should not be used as a substitute for professional medical advice, diagnosis, or treatment. Always consult with a qualified healthcare provider or clinician for any health-related concerns or questions about your LH levels or fertility.