Start with dates she shares
Ask for her period dates, or open a cycle link she sent.
Cycle length
Period length
Ovulation day
Period days logged: 0 days
Period dates she shared
Tap every day she bled to add or remove it
Start with dates she shares
Is she pregnant?
Understand the timing together, using dates she chooses to share.
No accountNo data storedShareable link
Work through the worry together
01
Ask, do not assume
Use only period dates she agrees to share. Enter bleeding days, not the day you had sex.
02
Explore that day
Hover or hold the date of sex to see its estimated phase. A lower-fertility label is not an all-clear; the summary shows today.
03
Support the next step
Help arrange advice or a test if she wants. Test from a missed period, or at least 21 days after the most recent unprotected sex if the due date is unknown.
No data stored.
periods.day has no accounts, cookies, analytics, or saved cycle data. Your entries live only in a link you can share. Nobody else can edit your entries.
Who made this?
Hello! I wanted to understand my body without sharing my data with advertisers. I also wanted to share knowledge about women's health. Feel free to share this website if you find this useful!
Pregnancy worries, shared responsibly
How can I help after recent unprotected sex?
Unprotected sex within the last 5 days? Discuss emergency contraception promptly with her and a pharmacist or sexual-health service. Options and time limits vary. Do not wait for the calendar; support her choice. Learn about emergency contraception
Can I tell if she is pregnant from her cycle?
No. Even accurate period dates do not establish the exact day of ovulation or whether pregnancy occurred. A calendar offers context; a pregnancy test at the right time is needed.
What if I pulled out?
Withdrawal can fail and does not rule out pregnancy. If pregnancy is not wanted, seek prompt advice about emergency contraception instead of relying on cycle timing.
How can I help without pressuring her?
Ask what support she wants, listen, and offer practical help getting advice or a test. Use and share cycle information only with her agreement. Healthcare decisions about her body are hers.
How are fertility percentages calculated?
These estimates use pregnancy data from 221 women who were actively trying for a baby and had stopped using contraception. They recorded each day whether they had intercourse. Li, Wilcox and Dunson (2015, Table 3) used a statistical model to estimate the chance of a clinical pregnancy from one act on a given cycle day. This does not mean the women had sex once every day. The study did not record whether ejaculation occurred inside the vagina. These figures therefore do not estimate the risk with withdrawal. Our calendar shifts the study’s curve to match the calculated ovulation day or the cycle day you set. This is an approximation, not a validated personal prediction. Days before the table starts use its first value. The percentages are population estimates, not your personal odds or a contraceptive method. Li, Wilcox & Dunson (2015)