How many copies did Space Travel Idle sell?

13k to 22k copies, based on its 539 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 owners: ≈ 13k–22k; from 539 reviews (Mixed)

A labeled estimate from the public review count (adjusted for release year), not exact sales. Owner data cross-checked with SteamSpy.

Does this actually work?

We left Space Travel Idle out and predicted the genre from its 8 similar games. Every figure here, including Space Travel Idle's, is estimated from Steam reviews, not self-reported sales.

Copies, estimated from reviews

typical (middle half) 1.2M–2.2M

best case 8.2M (Slay the Spire)

Games like Space Travel Idle

The middle of these games

≈ 1.2M–2.2M copies

≈ $6.0M–$18.8M after Steam's cut

from ~51k reviews

Only the top fifth of 2019’s Steam releases earned about $34k gross, so plan for that or less.

7 of your 8 similar games are hits.

No genre covers most of your similar games. The closest is Card Battler (3 of 8), so the genre you lead with is still undecided.

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–10.2M copies, ≈ $43.1M–$116.0M after Steam's cut.

What it took to get here

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

The genre you'd be entering

Your set: Your set clusters on Card Battler (3 of 8) and Card Game (3 of 8).
The winners: Winners here lead with Roguelike Deckbuilder + Card Game, priced around $25.
The era: The games you compared span 2019 to 2026, and 1 of your 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	51k reviews Mixed	Free to PlayCard Game
Library Of Ruina 2021	Est. copies ≈ 1.1M–1.8M SteamSpy 1M–2M	Est. revenue $9.1M–$24.5M after Steam's cut $16.6M–$37.7M before the cut	$29.99	45k reviews Very Positive	Story RichCard Game
觅长生 2023	Est. copies ≈ 792k–1.3M SteamSpy 1M–2M	Est. revenue $3.3M–$8.8M after Steam's cut $5.9M–$13.5M before the cut	$14.99	32k reviews Very Positive	RPGOpen World
Slay the Spire 2019	Est. copies ≈ 6.3M–10.2M 4.3x vs typical SteamSpy 5M–10M	Est. revenue $43.1M–$116.0M after Steam's cut $78.4M–$178.5M before the cut	$24.99	218k reviews Overwhelmingly Positive	Roguelike DeckbuilderCard Game
Stormworks: Build and Rescue 2020	Est. copies ≈ 1.5M–2.4M SteamSpy 1M–2M	Est. revenue $10.2M–$27.4M after Steam's cut $18.5M–$42.2M before the 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 $71k–$190k after Steam's cut $128k–$292k before the cut	$15.99	647 reviews Very Positive	Early AccessDeckbuilding
Drunken Wrestlers 2 2019	Est. copies ≈ 540k–878k SteamSpy 500k–1M	Est. revenue $593k–$1.6M after Steam's cut $1.1M–$2.5M before the cut	$3.99	19k reviews Very Positive	Early AccessMultiplayer