Spider Solitaire online: pick your number of suits

Spider Solitaire comes in three strengths, and the only thing that changes between them is how many suits are shuffled into the two decks. One suit, two suits or four: the layout, the ten columns and the five deals from the stock stay exactly the same. What changes is how often you get to the end.

We measured that directly. A computer player that sees only the face-up cards and never takes a move back won 52.8% of one-suit games, 5.7% of two-suit games and 0.2% of four-suit games. Those are floors, not the true odds: at two and four suits our program is a weak player, and a patient human with Undo does far better. For comparison, a published study that let a solver see every card found four-suit Spider winnable 98.5% of the time.

This page is the map. Use it to choose a level, see where Spider sits among the other games on spidersolitaire.us, and jump to the page for the version you want to play.

Three versions, three very different games

The middle column tells the story better than the win rate. With one suit, our program cleared nearly five of the eight runs even across games it lost. Add a second suit and it averaged less than one completed run per game. At four suits, a finished run became a rare event. Every extra suit makes it harder to build a run you are allowed to move, and in Spider a run you cannot move is a run that blocks everything beneath it.

The published ceiling is the other half of the picture. Blake and Gent (Journal of Artificial Intelligence Research, 2026) report four-suit Spider at 98.5% winnable (±1.5%) for a solver that knows where every card is. Almost every four-suit deal can be won in principle. Winning one without that knowledge is a different matter.

Which level should you start with?

New to Spider: one suit

Every card belongs to the same suit, so any card can go on one rank higher and every run you build can move. It is the easiest version to learn the flow of the game: build, clear a column, deal, repeat. Our program won just over half its games, so expect to win often once you plan ahead. Play Spider with one suit.

Comfortable with one suit: two suits

Now the deck mixes two suits. You can still place any card on one rank higher, whatever its suit, but only runs of a single suit move as a group. That one restriction took our program from a coin flip down to about one win in eighteen games. It is the step where Undo and planning start to matter most. Play Spider with two suits.

Looking for a long challenge: four suits

All four suits, two of each. Our program won 4 of its 2,000 games, which says more about the program than the game, given the 98.5% published ceiling. Treat each four-suit deal as a puzzle to be worked out over a long sitting, not something to finish in ten minutes. Play Spider with four suits.

Spider on the solitaire difficulty ladder

We ran the same kind of study on all twelve games on the site, using the rules our own games follow. Two numbers matter. The floor is what a simple program won playing only with the cards it could see. The ceiling is the share of deals a solver proved winnable when it could see everything; where some deals were left undecided, it is a range.

Read the table in both directions. One-suit Spider has the highest floor of anything we tested: it is the game where simply playing sensibly wins most often. Four-suit Spider has one of the highest ceilings and the lowest floor, which makes it the game where skill is worth the most. The Yukon, Alaska and multi-suit Spider floors come from our weakest programs, so treat those as a sign of difficulty rather than a prediction of your own results.

If you like Spider's planning but want every card in view from the start, try FreeCell. If you want the classic seven-column game at its toughest, try Solitaire Turn 3. The full list is on the games page.

What you get when you play here

• Free, with nothing to download, install or sign up for.
• Large, clear cards and a zoom control, in any modern browser on desktop, tablet or phone.
• Help when you need it: Hint, Undo as often as you like, Restart and Auto Play.
• Move cards by dragging them or by tapping the card and then its new spot.
• Wins, time and moves shown for the game you are playing, plus sound on or off, fullscreen and a choice of table colors.

How we tested the three Spider levels, step by step

The spidersolitaire.us team ran these tests in September 2026 to answer one question: on the rules our own Spider uses, how much does each added suit cost you?

1. Read the rules out of our game code. Two decks, 104 cards, ten columns of six and five cards, 50 cards left to deal in five rounds of ten, no redeal. A card can go on any card one rank higher, only single-suit runs move together, any card may fill an empty column, and a finished King-to-Ace run leaves the table on its own. We assumed you cannot deal while a column is empty; the game warns you at that point, but we did not confirm the behavior in a browser.
2. Wrote the game as a program that plays by exactly those rules, with one, two or four suits.
3. Dealt numbered shuffles. Each deal comes from a numbered seed so the whole test can be repeated. The program's scoring was set on deals 1 to 30, and every reported game used deals from 100,001 upward, which played no part in that setup.
4. Chose a player that sees what you see. It looks a short way ahead using the face-up cards only, treats cards it has not uncovered as unknown, and never undoes a move. That makes each result a floor.
5. Played the games through: 4,000 with one suit, 4,000 with two suits and 2,000 with four.
6. Compared with published work. The only published Spider figure we found is the four-suit 98.5% from Blake and Gent, for a solver that sees every card. We did not build such a solver ourselves, so that figure is used as the ceiling.
7. Put a margin of error on each result. A 95% range such as 5.0–6.5% for two suits means the true win rate for this program almost certainly lies inside it.
8. Stated the limits. The program is weak at two and four suits, so its numbers show how steep the difficulty is, not how often a careful human wins.

Under the hood

The study is written in Python 3.11 using only the standard library. Spider lives in its own module, spider.py, and a shared runner handed the deals out to 19 worker processes on a 20-core machine using Python's multiprocessing. On each turn the player runs a best-first search of up to 250 reachable positions and picks the most promising line, scoring same-suit links, uncovered cards and empty columns. Each percentage comes with a Wilson score 95% interval.

An AI assistant, Claude by Anthropic, helped us write and check the simulation code and draft this page. It did not supply any of the numbers: every figure is the output of running the code, and the team compared the results with the published research before publishing.

By Admin, spidersolitaire.us (Solitairen OOD). Study date: 18 September 2026.

Common questions about the three levels

Is the game on this page one suit or more?

This page opens the one-suit game. The two-suit and four-suit versions each have their own page, linked above.

How much harder is two suits than one, really?

For our program, roughly nine times harder: 52.8% of games won against 5.7%. A human who plans and uses Undo will narrow that gap, but the jump is real.

If 98.5% of four-suit deals can be won, why do I lose so often?

That figure is for a solver that knows every hidden card. You do not, and in four-suit Spider most of the table starts face down. The gap between what is possible and what you can see is the whole challenge.

Do the suits change how the cards are dealt?

No. The deal, the columns and the five stock rounds are identical in every version. Only the mix of suits differs.

Where do I go after choosing a level?

Strategy for each level is on its own page, and longer pieces on the study go up on our blog.