Color isn't the whole story
Color, flow, timing, and cycle history all matter. Color shifts within a single period are normal: brown at the start, bright red as flow picks up, dark red mid-period, brown again at the end. What stands out is consistency - if every period suddenly looks different, that's worth tracking.
When to see a doctor
Gray blood, heavy clots bigger than a quarter, soaking through a pad/tampon every hour, periods longer than 7 days, or spotting between periods that doesn't fit ovulation or hormonal birth control. The discharge decoder handles non-period discharge, and the menstrual cycle calculator can help you track patterns.
Frequently asked questions
What does brown blood mean?
Brown blood is older blood that took longer to leave the uterus and oxidized. It's normal at the very start or end of a period. Brown spotting mid-cycle can be ovulation-related or implantation-related (very early pregnancy).
Is black blood dangerous?
Almost always not. Black blood is just very old, very oxidized blood. It can show up at the start or tail end of a period, or with light flow. Worth a check if it comes with severe pain, foul smell, or fever.
When is heavy bleeding 'too heavy'?
Soaking through a pad or tampon every hour for several hours in a row, passing clots bigger than a quarter, periods lasting more than 7 days, or any bleeding heavy enough to cause anemia. Each one is worth a doctor visit.
These calculators give estimates based on cycle averages and standard formulas. They are for general information only and are not medical advice. For anything concerning your health or pregnancy, talk to a qualified healthcare provider.