Coin limit

Note: Code shown in this section is recreated and may not be the exact code used by the game

A coin limit is the maximum number of coins that can be collected or saved in a given area. Some courses allow infinite coins to be collected. However, in the NTSC (American) version, the coin counter is programmed to stay at the maximum of 999.

There are two types of coin limits - the 999 coin limit within the course (except Japanese version), and the 255 coin limit that is saved in the save-able records.

The 999 coin limit

The limit is intentionally put in by the programmers to prevent the game to count up coins greater than 999:

if(coin_counter > 999) {
coin_counter := 999;
}

The 255 coin limit

Separately, there is an unintentional coin limit involving the saved coin score. This value overflows and is set to 0 if the number of coins Mario collected in the course is a multiple of 256. (Not within the course, but when recording the saved coin score after Mario exits the course.) Thus, the easiest way to obtain the highest possible saved coin score in a level is to simply collect 255 coins. 511 and 767 also produce a saved coin score of 255, but collecting more than 255 coins is not as efficient as collecting a star when 255 coins have been collected. 1,023, 1,279, etc. also save as 255, but these coin scores cannot be obtained in the NTSC version.

Coin limit for each course

Normally, the number of available coins in the course prevents the player from getting an excess number of coins to reach either of the coin limits. Nonetheless, there are ways for a player to perform infinite coin glitches such as moneybag duplication, cloning or utilizing certain exploits of the game, allowing infinite coin glitches in certain courses.

Some courses have only a finite number of coins; in these courses, cloning is impossible and there are no infinite coin glitches. The three courses that don't fall into either of these categories, namely Tick Tock Clock, Rainbow Ride, and Bowser in the Fire Sea, allow for clones to be created, but due to a lack of loading zones, the clones fill up the game's object slots. Due to this, there is a limitation on the number of coins that can be collected within these three courses.

In the table below, 999 coins represent stages with infinite coin glitches available that does not have clones occupy object slots making the game crash.

Course	Available coins	Maximum possible coins	Strategy
Save-able courses
Bob-omb Battlefield	146 coins	999 coins	Breaking/Disappearing cork box glitch Ride cancel (Cloning is possible but limited)
Whomp's Fortress	141 coins	999 coins	Breaking/Disappearing cork box glitch
Jolly Roger Bay	104 coins	104 coins
Cool, Cool Mountain	154 coins	154 coins
Big Boo's Haunt	151 coins	151 coins
Hazy Maze Cave	139 coins	139 coins
Lethal Lava Land	133 coins	133 coins
Shifting Sand Land	136 coins	999 coins	Breaking/Disappearing cork box glitch (Cloning is possible but limited)
Dire, Dire Docks	106 coins	999 coins	Water shell cloning, loading area reset
Snowman's Land	127 coins	999 coins	Moneybag duplication Time stop coin collection, loading zone
Wet-Dry World	152 coins	999 coins	Chuckya cloning, loading area reset
Tall, Tall Mountain	137 coins	999 coins	Bob-omb cloning, loading area reset
Tiny-Huge Island	192 coins*	999 coins	Piranha plant glitch Time stop coin collection, loading zone Cloning using chuckya Ride cancel
Tick Tock Clock	128 coins	279 coins**	Bob-omb cloning, with limit due to object slots
Rainbow Ride	146 coins	290 coins**	Bob-omb cloning, with limit due to object slots
Non-saveable courses
Bowser in the Dark World	80 coins	999 coins	Infinite coins from Bowser's fire
Bowser in the Fire Sea	80 coins	250 coins**	Bob-omb cloning, with limit due to object slots
Bowser in the Sky	76 coins	999 coins	Infinite coins from Bowser's fire
*Including the impossible coin, underground, to the left of the line of 3 coins **Maximum number of objects allowed: 239 for TTC, and 227 in RR.

Unbounded Coin Limit Glitch (Japanese version)

In the Japanese version, there is no coin limit within the courses. When the coin counter reaches a value of 1,000, the game runs a few lines of code wherein there is a typo:

if(coin_counter > 999) {
lives_counter := 999;
}

This should be the following:

if(coin_counter > 999) {
coin_counter := 999;
}

Because the lives counter is a signed short, the value of 999 overflows to -25. This is displayed in the HUD as "M25." (The "M" presumably means "minus.")

After reaching a value of 32,767, the coin display remains at that value. After that, only the hidden coin count keeps incrementing. That is because the coin count is a signed short, so if the player collects more coins, the coin counter will overflow to -32,768. Since -32768 is not greater than 32,767, the coin display will not increment any further. If one were to collect a 65,636^th coin (65,536 for the overflow and 100 for the star), a second 100 coin star would spawn. This was a part of a strategy that could have been applied to collect "To the Top of the Fortress" in 0x A presses, but it wasn't because a faster 0xA strategy was discovered for that star.