Why the basics of PERIOD. stay free, and how that actually works

When Lisa started building PERIOD. one thing was non-negotiable: the basics had to be free. Not free-for-now, not free-until-we-get-big. Just free, and that is the promise we keep honouring.

Because here is what frustrated her most about every other period app out there: the moment you wanted to actually understand your cycle, not just see a red dot on a calendar, you hit a paywall. The big apps charge a hefty monthly fee for insights that should just be part of knowing your own body. That felt wrong. It still does.

The Duolingo model

So we built PERIOD. on a different model. One that Luis von Ahn, the founder of Duolingo, described better than we ever could: if you can afford to pay for extra features, you do, and that makes it possible for everyone else to use the basics for free. The people who want more subsidise access for the people who just need the essentials.

This is not charity. It is a business model that works. Duolingo is a billion-dollar company with over 500 million users, the vast majority of whom learn for free. It proves you can build a product that is accessible to everyone while being financially healthy. We believe the same applies to health apps.

What stays free?

At PERIOD. the basics stay free. And by "basics" we do not mean a stripped-down version that is useless. We mean the core:

• Track your cycle, log your period, flow intensity, and symptoms.
• Predict your next period, based on your own data, not a generic average.
• Daily insights, understand what is happening in your body every day of your cycle.
• Reminders for your period and your pill.
• Log symptoms and see them back in your calendar.

That is not going anywhere, no matter what. No upsells that block you, no features that disappear behind a wall after a month.

What does cost money?

What does cost money is the deeper layer: PERIOD. plus, at 3.99 euros a month or 34.99 euros a year. Think advanced pattern analysis that shows trends across multiple cycles. PDF reports you can share with your GP or gynaecologist. Detailed nutrition and workout advice per phase.

These are features that go beyond the basics, for users who want to go deeper. They are valuable, but not essential to understanding your cycle. And that is the difference: with PERIOD. you do not have to pay to understand the basics.

The problem with the rest of the market

Let us be honest about what is happening in the market. Most cycle apps use the freemium model as bait: they show you just enough to make you curious, then hide everything truly useful behind a subscription. The best-known apps charge a hefty subscription for that. And some apps that present themselves as free earn their money from your data in other ways.

We think that is fundamentally wrong. Insight into your own body is not a luxury product. It is a right. A 16-year-old who just started menstruating deserves the same information as someone who can spend 50 euros a month on health apps.

Why this matters beyond just pricing

Because we believe that understanding your own body is not a luxury. A 17-year-old in Rotterdam and a 35-year-old in Amsterdam both deserve to know why they are exhausted on day 21 of their cycle. Neither should have to pay to find out.

The money we make from premium features funds three things: keeping PERIOD. running and improving, building new features that genuinely help, and eventually, partnerships with charities and organisations working on women's health access worldwide. The more people who choose to pay for extras, the more we can give back.

A promise, not a marketing trick

We know that "free" is a word companies use easily and break even more easily. That is why we are putting it in writing here: the basics of PERIOD. will stay free. Not as a marketing strategy, but as a principle. It is the reason we exist.

That is the model. Simple, honest, and built around the belief that information about your own health should never be behind a wall.

Download PERIOD. (App Store · Google Play) It is free. It will stay free where it matters most.