Pregnancy Chance Per Day After Period

To get started, simply enter your last period start date and average cycle length into our interactive Pregnancy Chance Calendar to calculate your personalized daily conception probabilities. For more precision, click through to Advanced Options. Our Related Calculators Advanced Pregnancy Chance Calculator 📊 Fertility Calculator by Age 🎂 One‑Time Pregnancy Calculator ⚡️ Due‑Date Calculator 🤰 … Read more

Contraceptive Methods You Should Never Mix

Some contraceptive pairs reduce protection or add risk. If you want to “double up,” choose methods that complement each other—not ones that fight or cancel out. Below are combinations most people should avoid, plus better substitutes. Pairs you shouldn’t mix Don’t mix Why it’s a bad combo Better instead Two external condoms or an external … Read more

How Effective is Using Two Contraceptives at Once?

Using two methods at the same time can lower pregnancy risk, especially if at least one method protects against user error. The calculator below estimates protection when you combine methods under typical or perfect use. Check your combined protection How the estimate works (plain math) Convert each method’s effectiveness to a failure rate. Example: 95% … Read more

Top Contraceptive Method Combinations for Maximum Protection

Some pairs of birth control work especially well together. Below are evidence-based combinations that increase pregnancy protection while keeping STI protection in mind. When you want precise numbers for your situation, use our Combined Contraceptive Effectiveness Calculator. How “combined effectiveness” works (in plain English) Each method has a small chance of failure in a given … Read more

Do Ovulation Apps Work? Evidence, Limits & Better Ways to Time Intercourse

Woman looking at calendar

Ovulation “prediction” sounds straightforward—until you look at real cycles. Many popular apps lean on calendar math, but ovulation varies by person and by month. Below is what independent studies and guidelines say, where tracking goes wrong, and practical (evidence-based) ways to time intercourse without overcomplicating your life. What the research actually says Key takeaways from … Read more