Flo vs Natural Cycles: Which One Should You Use?

Natural Cycles suits people who want an FDA-cleared, app-based birth control method and are willing to take a daily temperature reading. Flo suits people who want a period and cycle tracker with a large content library and community, and don't need it to work as contraception. Veya is a tracker, not birth control.

By Veya Team • Published June 8, 2026 • Last reviewed October 9, 2026 • 9 min read • App Comparison

Full Transparency

This comparison is published by Holland Neurotech Inc., the company behind Veya. We've included Veya as a third option where relevant. We've done our best to compare each app fairly based on publicly available features, pricing, and user reviews. If Flo or Natural Cycles is the better fit for you, use it.

How We Compared

To compare Flo and Natural Cycles, we checked both apps against the same checklist: what each app is designed to do, prediction accuracy, wearable support, pricing and free tier, and privacy practices. For each app we reviewed its current App Store listing, published pricing, privacy policy, and recent user reviews. Neither Flo nor Natural Cycles paid for placement or influenced the verdict.

Last reviewed: October 9, 2026

Quick Answer

Flo and Natural Cycles are not the same kind of app. Here's how they split by use case, with sources linked where we cite facts (App Store details are as of October 2026):

This article is educational and not medical advice. Choosing a birth control method is a decision to make with a healthcare provider who knows your history.

Flo and Natural Cycles show up in the same searches all the time, so it's easy to assume they're rivals doing the same thing. They aren't. Flo is a period tracker that predicts your cycle. Natural Cycles is a birth control method that happens to live in an app. One estimates your fertile days from your calendar. The other received an FDA De Novo grant in August 2018 as stand-alone software for preventing or planning pregnancy, and it confirms ovulation from your daily temperature.

That single difference decides most of this comparison. If you're choosing between them, the real question isn't "which app is better," it's "do I want a tracker or do I want a method." We'll walk through what each one actually does, then introduce a third option that fits a different need.

The Short Version

If you're in a rush, here's the quick breakdown:

Flo Natural Cycles Veya
Best for Easy tracking, content, community App-based birth control All-in-one tracking
FDA-cleared as birth control No Yes (2018) No
How it works Calendar predictions Confirms ovulation by temperature Cycle + lifestyle tracking
Platform iOS + Android iOS + Android iOS only (+ web app)
Free tier Yes, usable No free tier listed Most features, no ads
Price $47.99–$59.99/year $149.99/year (annual plan includes an NC° Band) ~$49.99/year
Wearables Apple Watch Oura, WHOOP, Apple Watch (S8+), Garmin Apple Watch, Oura, Garmin

Prices and wearables are from each app's US App Store listing as of October 2026 (Flo, Natural Cycles). FDA status: De Novo grant DEN170052. Veya figures are our own.

Want more detail? Keep reading.

What is the real difference between Flo and Natural Cycles?

Here's the part that matters most, so it's worth saying plainly before the feature lists.

Flo predicts. It looks at the cycle data you log and estimates when your period and fertile window will probably happen. Those estimates are useful for knowing what to expect, but they're not measuring what your body is actually doing on a given day, and Flo does not claim to be birth control.

Natural Cycles measures. It uses your basal body temperature to confirm whether you've ovulated, then tells you whether today is a "green day" (not fertile) or a "red day" (use protection or abstain). That measurement approach is what the FDA reviewed when it granted Natural Cycles its De Novo request. In the FDA's decision summary, real-world data from 15,570 women gave a typical-use Pearl Index of 6.5 (about 6.5 pregnancies per 100 women per year) and a perfect-use Pearl Index of 1.

One quick but important note on what "the app is your birth control" means: on red days, Natural Cycles tells you to abstain or use a barrier method. The app does not physically prevent pregnancy. It tells you which days carry risk so you can act on that. Keep that in mind as you read the rest.

What do you get with Flo?

Flo is one of the most widely used period trackers: its App Store listing cites over 570 million downloads worldwide (Flo's own figure, as of October 2026). Just know going in that it's a tracker, not a contraceptive.

Features

  • Cycle and period tracking with AI-powered predictions
  • Fertile window and ovulation estimates (conception mode)
  • Daily articles and expert-backed content, per its listing
  • Virtual health assistant (Flo Premium)
  • Secret Chats for tips from other members (Premium, per its listing)
  • Pregnancy Mode with checklists and expert guidance (in-depth features are Premium)
  • Apple Health integration and an Apple Watch companion app
  • Anonymous Mode for logging without linking data to your identity

Strengths

Core tracking is free to download. The listing says the app's core tools are free, with Premium adding more.

Content and community features. The listing describes daily articles and expert-backed content, plus Secret Chats for tips from other members. If you want to learn while you track, that's a real draw.

It's familiar and well-rated. The listing shows 4.7 stars from about 2 million ratings (as of October 2026).

Limitations

It is not birth control. This is the big one for this comparison. Flo's fertile-window estimates are predictions, not confirmation of ovulation, and we found no FDA authorization for it as contraception (the FDA record we checked covers Natural Cycles). Don't use it as a contraceptive method.

Predictions weaken with irregular cycles. Calendar-based estimates generally get less reliable when your cycles vary a lot.

Privacy history. Flo settled FTC allegations in 2021 over sharing health data, and a separate class action over the same data sharing has a proposed settlement awaiting final approval. Flo has since added Anonymous Mode. More on this in the privacy section.

Premium upsells. The virtual health assistant, Secret Chats, and in-depth pregnancy features are listed under Premium.

Pricing

Free: Free to download, with core tracking tools included, per the listing.

Flo Premium: annual plans are listed at $47.99–$59.99 in the US App Store (as of October 2026). Premium is listed as adding the virtual health assistant, Secret Chats, and in-depth pregnancy features.

Download: Available on iOS and Android

📆 Period Calculator

Predict your next 6 periods instantly.

Try It Free

What do you get with Natural Cycles?

Natural Cycles is a different animal. In August 2018 it received an FDA De Novo grant (21 CFR 884.5370, Class II) for stand-alone software that can be used to prevent pregnancy or plan one. Its App Store listing describes it as non-hormonal contraception, and it works by learning your cycle from your temperature.

Features

  • FDA-cleared birth control based on basal body temperature
  • Also covered by the FDA grant for planning pregnancy (one app, two modes)
  • Daily "green day / red day" fertility status
  • Confirms ovulation rather than only predicting it
  • Reads temperature from an NC° Band (offered with the annual plan), a basal thermometer, an Oura Ring, WHOOP, an Apple Watch (Series 8 or newer), or a compatible Garmin, per its listing

Strengths

It's an actual method, not a guess. Because it measures temperature and confirms ovulation, Natural Cycles can be used as birth control. In the FDA's decision summary, the typical-use Pearl Index was 6.5 and the perfect-use Pearl Index was 1. If app-based contraception is what you're after, this is the one with an FDA grant to do it.

Hormone-free. For people who can't or don't want to use hormonal birth control, a temperature-based method is a real alternative worth discussing with a provider.

It works with wearables you may already own. If you have an Oura Ring, WHOOP, a newer Apple Watch, or a Garmin, the listing says you can use it to measure temperature. Oura's support page also notes the Natural Cycles partnership.

Limitations

It needs daily temperature data. The method depends on a reading each day, so disrupted sleep, travel, and irregular schedules can degrade its accuracy.

It confirms ovulation after it happens. Because body temperature rises after ovulation, the method confirms it in hindsight rather than predicting it far ahead.

It may be a weaker fit for very irregular cycles. Temperature-based methods generally work best with fairly regular cycles, so if yours vary a lot, talk it through with a provider.

No free tier and it's the pricier option. We didn't find a free tier on its listing, and the subscription plus any wearable adds up.

Pricing

Subscription only: $21.99/month or $149.99/year in the US App Store (as of October 2026). The listing says the annual subscription comes with a free NC° Band. Pricing varies by plan and promotion, so check naturalcycles.com for current rates.

Download: Available on iOS and Android, or at naturalcycles.com

🥚 Ovulation Calculator

Find your fertile window and ovulation day.

Try It Free

Is there a third option besides Flo and Natural Cycles?

Flo and Natural Cycles sit at two ends of a line: one is a free tracker, the other is a paid method. Veya is a different shape entirely. It's built to track your whole health picture, not just your cycle. It's worth knowing about, but it's honest to say up front: like Flo, it is not birth control.

What It Adds

  • Cycle tracking with automatic phase detection and fertility predictions
  • BBT from Apple Watch, Oura Ring, or Garmin, plus manual LH and cervical mucus logging
  • Mood, sleep, fitness, and nutrition tracking built in
  • Custom habit tracking with auto-updating streaks
  • Correlation insights showing how your lifestyle affects your cycle
  • Pregnancy mode, plus PCOS and perimenopause support
  • No ads, no data selling

Why Consider It

The pitch is that you don't need three apps. Instead of one app for your cycle, another for food, and a third for mood, Veya brings them together and then shows the connections, like how your sleep affects your mood in the luteal phase. The free tier includes most features with no ads. For comparison, Flo's core tools are free to download and Natural Cycles is subscription-based.

Honest Limitations

  • Not birth control. Veya is a tracker. It is not FDA-cleared as contraception. If app-based birth control is your goal, Natural Cycles is the cleared option.
  • iOS only. There's no Android app yet. A web app is available, but the full experience is iPhone-only right now.
  • Smaller community. It doesn't have Flo's user base. If in-app community matters to you, this isn't the place for it yet.
  • Newer app. Fewer reviews and a shorter track record than Flo or Natural Cycles.
  • AI features are premium. The AI assistant (Ask Veya) requires a subscription (~$9.99/month or ~$49.99/year).

Pricing

Free: Cycle, mood, sleep, fitness, nutrition, and habit tracking. No ads.

Premium: ~$9.99/month or ~$49.99/year for AI features and advanced insights.

Download: Available on iOS App Store

Side-by-Side Feature Comparison

Here's every major feature compared across all three apps. Check marks mean the feature is included, locks mean it requires a paid subscription, warnings mean it's limited, and X marks mean we didn't find it listed.

Feature Flo Natural Cycles Veya
Cycle and period tracking ✅ ✅ ✅
FDA-cleared as birth control ❌ ✅ ❌
Confirms ovulation (temperature) ❌ ✅ ✅ With wearable
Fertile-window prediction ✅ ✅ ✅
Wearable integration ⚠️ Apple Watch ✅ Oura, WHOOP, Apple Watch, Garmin ✅ Apple Watch, Oura, Garmin
Mood, sleep, nutrition tracking ⚠️ Basic ❌ ✅ Detailed
Health content library ✅ Large ⚠️ Some ⚠️ Some
Community 🔒 Secret Chats (Premium) ❌ ❌
Pregnancy mode ✅ Listed (in-depth features Premium) ✅ ✅
AI assistant 🔒 Paid ❌ 🔒 Paid
Privacy practices ⚠️ FTC order and class action ⚠️ Medical device; read its policy ✅ Strong, no ads
Free tier ✅ Core tools free ❌ None listed ✅ Generous, no ads
Price (annual) $47.99–$59.99/yr $149.99/yr ~$49.99/yr

Should you choose Flo, Natural Cycles, or Veya?

There's no single "best" app here, because they're built for different jobs. Here's the honest breakdown:

Choose Flo if:

  • You want a free, easy period tracker and don't need it to be birth control
  • Health education articles and community features matter to you
  • You want pregnancy checklists and guidance (check which parts are free)
  • Your cycles are fairly regular and you mainly want to know what's coming
  • You're comfortable with Flo's privacy practices, or you'll use Anonymous Mode

Choose Natural Cycles if:

  • You want app-based birth control backed by an FDA grant
  • You prefer a hormone-free method and have talked it through with a provider
  • You already own an Oura Ring, a newer Apple Watch, or a Garmin
  • You have reasonably regular cycles and a consistent sleep routine
  • You're willing to pay and to take a temperature reading each day

Choose Veya if:

  • You want cycle, mood, sleep, fitness, nutrition, and habit tracking in one app
  • You track with a wearable and want that data connected to your cycle
  • You want to see how your lifestyle affects your cycle and symptoms
  • You want a free tier with no ads
  • You don't need the app itself to be your birth control method

Natural Cycles vs Flo: which should you pick?

Pick Natural Cycles if you want an app that is authorized by the FDA to be used as contraception, you're comfortable with a daily temperature reading (from a band, thermometer, or compatible wearable), and a subscription fits your budget. Talk it through with a healthcare provider first.

Pick Flo if you want a period and cycle tracker with articles and community features, a free-to-download app, and you don't need the app itself to prevent pregnancy. Flo's estimates are predictions, not a birth control method.

If you can't decide, ask what you need the app to do: estimate your next period, or act as your method. That single question settles most Natural Cycles vs Flo choices.

Is Flo or Natural Cycles better for privacy?

Cycle and fertility data is some of the most sensitive information you can put in an app, so privacy deserves real attention with both of these.

Flo: FTC order, class action, and Anonymous Mode

In June 2021 the FTC finalized an order against Flo over allegations that it shared sensitive health data with companies including Facebook and Google despite promising privacy; the order requires consent before sharing health information and carried no fine. A separate class action over the same 2016–2019 data sharing reached a proposed $59.5M settlement with Google, Flo and Flurry (Flo’s share: $8M; the defendants deny wrongdoing). It received preliminary approval in April 2026, with a final approval hearing set for October 29, 2026.

Since then, Flo has added Anonymous Mode, which its listing describes as using the app without personal identifiers linked to your health data. That's a real step. Whether the history changes your decision is personal, but it's worth knowing before you hand over your data.

Natural Cycles: A Regulated Device

Natural Cycles is a regulated medical device (see its FDA De Novo grant), and its App Store seller is NaturalCycles Nordic AB. We didn't verify its data practices, so as with any health app, read the current privacy policy to see what's collected and shared.

Veya: Privacy-Focused, Smaller Scale

Veya doesn't run ads and doesn't sell user data. It's a newer, smaller, US-based company without the years of public scrutiny that the bigger names have been through. The no-ads, no-data-selling approach is a meaningful commitment, just at a smaller scale.

Frequently Asked Questions

Can you use Flo as birth control?

No. Flo is a period and cycle tracker, and we found no FDA authorization for it as contraception; Flo's listing describes a period and pregnancy tracker. Natural Cycles is the app with an FDA De Novo grant for preventing pregnancy, and it works differently: it confirms ovulation from your daily temperature rather than estimating fertile days from your calendar. If you want an app to use as a birth control method, that distinction is the reason these two apps are not interchangeable.

Is Natural Cycles more accurate than Flo?

They do different jobs, so a single accuracy number is a poor comparison. Natural Cycles uses your basal body temperature to confirm ovulation, and in the FDA's decision summary real-world data from 15,570 women gave a typical-use Pearl Index of 6.5 (about 6.5 pregnancies per 100 women per year) and a perfect-use Pearl Index of 1. Flo's predictions are estimates from your logged cycle history, they do not measure whether ovulation happened, and calendar-based estimates generally get less reliable when cycles are irregular.

How much does Natural Cycles cost compared to Flo?

In the US App Store as of October 2026, Natural Cycles lists $21.99 per month or $149.99 per year, and the listing says the annual subscription comes with a free NC° Band; we didn't find a free tier listed. Flo is free to download, with Flo Premium annual plans listed at $47.99 to $59.99. Prices change with promotions, so check each app before subscribing.

Is Flo or Natural Cycles better for privacy?

They have different footings. Flo settled FTC allegations in 2021 over sharing health data with companies including Facebook and Google, and a proposed $59.5M class action settlement (with Google, Flo and Flurry; Flo's share is $8M) received preliminary approval in April 2026, with a final approval hearing set for October 29, 2026. Flo has since added Anonymous Mode. Natural Cycles is a regulated medical device, and we didn't verify its data practices. Read each company's current policy and decide what you are comfortable with.

Do I need a thermometer for Natural Cycles?

You need temperature data, but not necessarily a separate thermometer. Natural Cycles' listing names an NC° Band (offered with the annual subscription), a basal thermometer, an Oura Ring, WHOOP, an Apple Watch Series 8 or newer, and compatible Garmin devices. Either way, the method depends on a daily temperature reading, so it needs reasonably consistent measurement timing to work well. Flo does not require temperature input.

Can I use Flo or Natural Cycles to get pregnant?

Both can help you plan a pregnancy. Flo's listing describes a conception-oriented tracker with in-depth features under Premium, and Natural Cycles' listing includes a Plan Pregnancy mode that uses temperature to track ovulation; the FDA grant covers planning pregnancy as well as preventing it. If you are trying to conceive, compare the free and paid options in each app.

Natural Cycles vs Flo: which one is meant for preventing pregnancy?

Natural Cycles. It holds an FDA De Novo grant for software used to prevent or plan pregnancy, while Flo is a period and cycle tracker whose predictions are estimates, not a contraceptive method. Choosing a birth control method is a decision to make with a healthcare provider.

Want to See More Apps Compared?

This guide focused on Flo vs Natural Cycles, but there are other options worth a look depending on what you need. If you're weighing ovulation apps specifically, or you just want to know how accurate any of these predictions really are, these go deeper.

Read next: Best Ovulation Tracker App 2026 (5 Apps Compared) →

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