Short version: Astral Lab is $6.99 once. Co-Star is $7.99 every month. Over two years that is $6.99 against $191.76. That is the whole argument, and the rest of this page is whether you agree that the rest of it matters.

Astral Lab vs Co-Star

Most comparisons between these two apps get written by people who have never opened either one. So this one starts with what is actually verifiable, and states plainly where the two apps are the same and where one of them is simply different.

Side by side

	Astral Lab	Co-Star
Price	$6.99 once	$7.99 per month
Cost over 1 year	$6.99	$95.88
Cost over 2 years	$6.99	$191.76
Subscription	None. Nothing renews.	Monthly, must be cancelled
In-app purchases	None	Yes
Works offline	Yes, zero internet permissions	No, charts are computed server-side
Where your birth data lives	On your device only	Transmitted to and stored by Co-Star
Ephemeris	VSOP87 (planets) + ELP-2000 (Moon)	JPL DE431
Profiles	Unlimited	Free tier is limited
Chart export	Not advertised	Not advertised
Social feed	None	Yes, the main feature
Daily push forecast	No	Yes

The price difference is not a rounding error

Co-Star at $7.99 a month is $95.88 in the first year. It is $191.76 in the second. Most people who install Co-Star do not intend to keep it for two years, and they should not have to: cancel it and the price stops. The point is narrower than "Co-Star is expensive". It is that the two products sell the same category at a price ratio of 1 : 14 in year one, and the only structural difference you are paying for is the social feed and the push notifications.

Astral Lab at $6.99 is a decision you make once and never revisit. There is no renewal screen, no card on file, and nothing to remember to cancel in eleven months. For anyone doing this seriously enough to care about chart accuracy, that is not a small thing.

Precision: the two apps are in the same league

It would be easy to imply that one of these calculates positions better. That would not be true. Co-Star uses JPL DE431 and Astral Lab uses VSOP87 for the planets and ELP-2000 for the Moon. VSOP87 is the standard analytic planetary theory that serious ephemeris software, Swiss Ephemeris included, is built on. Both are professional-grade. Both will put Neptune within a fraction of a degree of where the big observatories put it.

If someone tells you Astral Lab is more accurate, ask which library they are comparing. The honest answer is that this is a difference of implementation, not of quality, and it should not be the reason you buy anything.

Offline and privacy: this is the real difference

Astral Lab requests zero internet permissions. Every calculation runs on the device. Your birth data, your family's charts, your clients' charts — they are never transmitted, because there is no channel to transmit them through. You can run it in aeroplane mode on a mountain.

Co-Star's model is the opposite: it computes charts on its servers, which means your birth data is sent to them and stored there, and the app needs a working connection to show you anything. That is not an accusation about how they treat it. It is a description of the architecture, and the architecture is what determines the privacy posture.

If you keep client charts, or your own birth data is something you would rather not hand to a company you do not know, that difference decides the question on its own.

What Astral Lab does not do

This section exists because most comparison pages written by the alternative app are useless. If any of these matter to you, Co-Star is the better choice and you should buy Co-Star:

No social feed. You cannot see friends' charts or comment on them. For a lot of people Co-Star's appeal is that ritual, not the astrology.
No daily personalised push forecast. Co-Star messages you. Astral Lab does not.
No shareable chart images designed for social platforms. If you post your chart, you will be doing it yourself.

What you get instead: unlimited saved profiles, real-time transits, aspect grids, and a tool that keeps working when the connection does not.

Who should buy which

Buy Astral Lab if…	Buy Co-Star if…
You already know how to read a chart and want the tool to be correct.	The social layer is the reason you installed it.
You keep client or family charts and do not want that data leaving the device.	You want a daily push notification telling you something.
You travel, work in aeroplane mode, or simply do not want a subscription renewing.	You want the free tier and are not in a hurry.
You want more than a handful of saved profiles.	You would rather not pay at all for basic features.

The honest version

If you want the social astrology experience, Co-Star is a legitimate product and this page will not pretend otherwise. If you want a chart you can trust, computed on your own device, at a price you pay once, Astral Lab is $6.99 and there is no subscription hiding behind it. Those are two different needs, and the subscription is what bridges them, not the chart quality.

Frequently asked questions

Is Astral Lab a free alternative to Co-Star?

No. Astral Lab is a $6.99 one-time purchase, not a free app. What it replaces is the subscription: Co-Star charges $7.99 every month, which is $95.88 in the first year and $191.76 over two years. Astral Lab is $6.99 once.

Does Astral Lab work without an internet connection?

Yes. Astral Lab requests zero internet permissions and every calculation happens on the device, so it works in aeroplane mode. Co-Star computes and serves its charts server-side, so it needs a connection.

Is Astral Lab as accurate as Co-Star?

Both use professional astronomical algorithms. Co-Star uses JPL DE431 and Astral Lab uses VSOP87 for planets and ELP-2000 for the Moon. VSOP87 is the same planetary theory the major Swiss Ephemeris library is built on, so this is a difference of implementation, not of quality. Neither is more accurate in a way that matters for a chart.

What does Astral Lab not do that Co-Star does?

Co-Star has a social layer: you see other people's charts and can comment on them. Astral Lab has no social features, no push-notification horoscopes, and no daily personalised forecast feed. If the appeal of Co-Star is the social feed rather than the chart, Astral Lab is not a replacement for that.

Is there a refund window?

Astral Lab is sold through Google Play, so the refund window is the one Google Play applies to app purchases, not a promise made here.

Other apps in the catalogue

Astral Lab is the astrology app in the catalogue. The other eleven cover sigils, servitors, runes, tarot, the I Ching, lucid dreaming, paranormal investigation, lunar phases and ESP — none of which have a direct competitor worth writing a comparison page about, which is why this is the only one. See all twelve apps, or take the whole set in the $29.99 bundle.