How to Take the Moon-Phase Compatibility Test You've Seen All Over AstroTok

Astrologers have long considered the moon to be central to our moods, using it to explain why people seem to be unhinged and restless during full moons, for example. But according to TikTok's latest moon-phase compatibility trend, looking at the moon phase at the time of your birth could reveal how compatible you are with a partner. The trend alleges that if you compare the phase of the moon on your birthday with that of your partner's, and your moon phases fit together to create a full moon, you might be a perfect match.

Users are testing their relationship's harmony by inputting their birthdate information into moon-phases compatibility calculators online to see if they complete each other. Then, they're using a video editor to create a clip demonstrating how well their moons align. The idea is that if you and your partner create a full moon, it means you've found your person.

"Apparently if your moon phases match up you are soulmates," user kaylahouston03 says, followed by their moon phases creating a full moon. But for other couples like Mattxkayla, whose moon phases were both in the waning gibbous phase, a soulmate connection just isn't written in the stars, according to this TikTok trend. "I think we got the worst moon phase," they wrote.

But you probably already know you can't trust everything you hear on the internet. So we asked an astrologer: does putting moon phases together really demonstrate compatibility? Lauren Ash, Sanctuary's resident astrologer and host of the podcast "Birth Chart Pls," isn't entirely convinced. But the moon can say a lot about your connection. Here's what you need to know.

Is Moon-Phase Compatibility Real?

If you've spent any time sifting through astrological compatibility, you might be aware of the fact that the sun, moon, and planets play a huge role. There are plenty of clues in the way your birth chart relates to your partner's that can show how well you might get along. However, assessing compatibility by looking at lunar phases is a totally different story. From an astrological perspective, the moon rules feelings, emotional responses, and intuition — which are all crucial in relationships. But the phases of the moon can dictate deeper parts of your personality, too.

"There are a total of eight moon phases in astrology, and each moon phase holds its own significant spiritual meaning and energy," Ash says. "And with the moon moving through all eight phases every 29.5 days, it's no wonder the phase of the moon you were born under can influence your personality and emotions so directly."

Ash adds that each phase of the moon can give off a certain vibe and, in turn, can discern your emotional needs and desires as well as how you express your feelings. For example, if you were born under a new moon, you're likely to lust after new adventures. Those born under a last quarter moon, she explains, tend to be more relaxed. Here's a breakdown:

  • New Moon: Exploration is important to you, especially when it comes to love. People born during a new moon tend to be "outgoing and ambitious people who wear their hearts on their sleeves," Ash says.
  • Waxing Crescent Moon: Those born during a waxing crescent moon are likely to be assertive go-getters. "They are bold in their intentions and like to express their affections directly," Ash explains.
  • First Quarter Moon: You might be extra self-sufficient and courageous if you were born under a first quarter moon. Those with a first quarter moon may enjoy being challenged and desire a partner who can encourage them to be better, Ash explains.
  • Waxing Gibbous: "Those born under the waxing moon gibbous phase are practical, grounded, and adaptable people," Ash says. When it comes to love, they tend to be compassionate and straightforward.
  • Full Moon: Full-moon babies tend to be emotionally sensitive and passionate when it comes to expressing affection. "They may seem guarded at first, but their loyalty and devotion runs deep," Ash says.
  • Waning Gibbous: "People born during a waning gibbous moon are very grounded in who they are and admire a partner with confidence," Ash explains. They're logical and amazing at listening to the needs of others and communicating their own.
  • Last Quarter: Going with the flow is second nature to those born during a last quarter moon — they appreciate a partner who's open to new things. "They are authentic and truthful people, but they also struggle to commit at times," Ash explains.
  • Waning Crescent: Vulnerability may not be your strong suit if you were born during a waning crescent moon. "They have a lot of passion and fire, but they will flee if they start to feel caged in," Ash says.

While your moon phase may be able to give you some insight into your personality — and comparing that with your partner's may clue you into similarities or differences between you both — it doesn't matter so much whether they line up to create a full moon. You can use what your moon phase says about you to see if your lunar vibe aligns with your partner's, but will they perfectly reveal a soul tie? Probably not.

When looking at compatibility, there are other areas of your chart to consider besides your moon phase, Ash explains. Your Venus sign, for example, describes your romantic language and how you express affection and require love. Your seventh-house placement, which is associated with partnerships, is also a powerful element to consider when assessing your compatibility.

How to Try the Moon-Phase Compatibility Test on TikTok

Moon phases may not have a significant meaning in terms of astrological compatibility, but if you want to test your celestial connection for yourself for fun, here's how.

To start, use a moon-phase calculator like or to calculate the moon phases for the days when you and your partner were born. If your moon phases mesh together and complete a full moon, you're a good pair, per the TikTok trend, and the same is debated if you have matching moon phases. If they don't fit, TikTok says it's likely you're not soulmate-level compatible.

If you want to get in on the TikTok trend and post a video, you'll need to have downloaded the CapCut video editing app. Screenshot your moon-phase images, click on "CapCut try this template" on a TikTok using this trend, then hit "use template" in CapCut and insert your screenshots. Finally, add text (some people have been adding their birthdays).

Looking at your moon sign or moon phase may tell you a little bit about your emotional drive or personality, and that info might help you understand how you work best within a relationship. But the truth is, relationship compatibility is complex, and discerning a soulmate connection takes a lot more than knowing whether your moon phases complete each other.

So don't take it personally if your moon phases don't align. You didn't think finding your soulmate was that simple, did you?