The transparent alternative to Natural Cycles.
Don't trust your fertility to a closed-source, proprietary algorithm. We use the well-studied symptothermal method, and all our logic is open source for you to audit.
How we differ from Natural Cycles
Natural Cycles was the first app cleared by the U.S. FDA as a form of birth control, back in 2018. That clearance is real, and we won't pretend otherwise: canihavesex.today is not FDA-cleared, and it is not a contraceptive. What we offer is a different trade-off — transparency instead of a proprietary algorithm.
Natural Cycles runs a closed algorithm; in the clinical data behind its FDA clearance it reported about 93% effectiveness with typical use. canihavesex.today uses the openly-documented symptothermal method — the same temperature-and-fluid approach studied for decades — and all of its logic is open source for you to read. Use any basal thermometer you already own (no proprietary device or ring), pay $69/year instead of a roughly $120/year subscription, or self-host it for free.
Common questions
Is canihavesex.today an alternative to Natural Cycles?
Yes, if you want a transparent, open-source tool and don't need FDA-cleared contraception. It reads the same core signs — basal body temperature and cervical fluid — works with any basal thermometer, and every line of its logic is auditable. But it's a fertility-awareness guide, not a contraceptive.
Is canihavesex.today FDA-cleared like Natural Cycles?
No. Natural Cycles was the first app cleared by the U.S. FDA as a form of birth control (2018). canihavesex.today is not FDA-cleared and does not claim to prevent pregnancy — it is a guide based on the symptothermal method, and it isn't medical advice.
How much does it cost compared to Natural Cycles?
$69/year or $420 once, each with a 14-day free trial — or free forever if you self-host. Natural Cycles is subscription-only (around $120/year) and pairs with its own thermometer or a compatible wearable.