How many copies did Space Travel Idle sell?

13k to 22k copies, based on its 540 Steam reviews. This is a labeled estimate from the review count, not exact sales.

How much revenue did Space Travel Idle make?

Space Travel Idle is free to play, so there is no copy-sales revenue to estimate.

How big is Space Travel Idle?

Estimated players who have it: ≈ 13k–22k; from 540 reviews (Mixed)

Copies are estimated from the public review count, adjusted for release year, and cross-checked against SteamSpy's own estimate.

Did the prediction match what actually happened?

We hid Space Travel Idle and predicted how it would do from its 8 similar games. Every figure here, including Space Travel Idle's, is estimated from Steam reviews.

Copies, estimated from reviews

typical (middle half) 1.3M–2.2M

best case 8.3M (Slay the Spire)

Games like Space Travel Idle

A typical game among these

≈ 1.3M–2.2M copies

≈ $6.1M–$18.9M after Steam's cut

from ~52k reviews

Only the top fifth of 2019's Steam releases earned $34k or more before Steam's cut, so plan for that or less.

7 of the 8 similar games are hits.

No genre covers most of these similar games. The closest is Card Battler (3 of 8), so its genre is hard to place.

Of the 416 indie games that passed 1,000 reviews in 2022, 11.8% were novel genre mixes and 88.2% stuck to an established genre. Published indie market research.

Best case: Slay the Spire at ≈ 6.3M–10.3M copies, ≈ $43.5M–$116.9M after Steam's cut.

What their first month looked like

About half the games that made it here had over 9k reviews in their first month; the range was 596 to 17k.

The genre you'd be entering

These games: The similar games share Card Battler (3 of 8) and Card Game (3 of 8).
The winners: Winners here lead with Roguelike Deckbuilder + Card Game, priced around $25.
When they shipped: The similar games span 2019 to 2026, and 1 of the 8 shipped in the last two years.

How these numbers were worked out

A hit here: 1,000+ reviews, roughly $150k+ before Steam's cut (a standard indie benchmark).

Copies come from each game's reviews times a sales-per-review rate that falls with release age, from about 31 for the most recent game here to about 36 for the oldest, then widened into a range; revenue rides on that estimate times price. Source: GameDiscoverCo (2020) and VG Insights (2021).

Similar games

Game	Est. copies	Est. revenue	Price	Reviews	Tags
Minion Masters 2019	Est. copies ≈ 1.9M–3.1M SteamSpy 500k–1M	Est. revenue Free	Free	65k reviews Very Positive	PvETrading Card Game
KARDS - The WW2 Card Game 2020	Est. copies ≈ 1.3M–2.1M SteamSpy 2M–5M	Est. revenue Free	Free	52k reviews Mixed	Free to PlayCard Game
Library Of Ruina 2021	Est. copies ≈ 1.1M–1.8M SteamSpy 1M–2M	Est. revenue $9.2M–$24.9M after Steam's cut $16.8M–$38.3M before Steam's cut	$29.99	45k reviews Very Positive	Story RichCard Game
觅长生 2023	Est. copies ≈ 797k–1.3M SteamSpy 1M–2M	Est. revenue $3.3M–$8.8M after Steam's cut $6.0M–$13.6M before Steam's cut	$14.99	32k reviews Very Positive	RPGOpen World
Slay the Spire 2019	Est. copies ≈ 6.3M–10.3M 4.2x vs typical SteamSpy 5M–10M	Est. revenue $43.5M–$116.9M after Steam's cut $79.0M–$179.8M before Steam's cut	$24.99	220k reviews Overwhelmingly Positive	Roguelike DeckbuilderCard Game
Stormworks: Build and Rescue 2020	Est. copies ≈ 1.5M–2.4M SteamSpy 1M–2M	Est. revenue $10.3M–$27.6M after Steam's cut $18.7M–$42.5M before Steam's cut	$24.99	60k reviews Very Positive	SandboxBase-Building
Rogue Voltage 2026	Est. copies ≈ 16k–26k too small to compare SteamSpy under 20k	Est. revenue $72k–$193k after Steam's cut $130k–$296k before Steam's cut	$15.99	657 reviews Very Positive	Early AccessDeckbuilding
Drunken Wrestlers 2 2019	Est. copies ≈ 541k–879k SteamSpy 500k–1M	Est. revenue $594k–$1.6M after Steam's cut $1.1M–$2.5M before Steam's cut	$3.99	19k reviews Very Positive	Early AccessMultiplayer