Sumplete

Sumplete is a daily number-logic puzzle where you cross out the right cells so the numbers left in each row and column hit their printed targets. It plays like a reverse Sudoku: you delete instead of place, and every grid has exactly one logical solution. A quick Daily 5x5 and a tougher Daily 7x7 refresh each day, with an Unlimited mode for sizes from 3x3 to 9x9.

What is Sumplete?

Sumplete is a daily number-logic puzzle built around a single, satisfyingly simple action: removing numbers until what is left balances. You are shown a square grid filled with numbers, with a target sum printed at the end of every row and below every column. The whole grid is solved when the kept numbers in each row add up to that row's target and every column does the same. Marking is fast and reversible: each cell cycles through three states on successive single clicks, going from blank, to a red cross that removes the number from the count, to a green circle that locks it in as kept, and back to blank again. Crossing out takes a number out of the total, while circling helps you reason without losing track of what you have committed to. Every puzzle has exactly one valid arrangement, so success comes from deduction rather than guesswork.

What sets Sumplete apart from the wave of Wordle-style games is that it is arithmetic and elimination rather than vocabulary or pattern hunting. There is no hidden answer you are trying to guess in a limited number of tries, and no green-yellow-gray color feedback. Instead the feedback is the math itself: a row is either balanced or it is not, and the grid tells you the truth as you go. It plays a little like a reverse Sudoku, where the goal is to take numbers away instead of placing them, which gives it a calmer, more deliberate feel than timed letter guessers.

Sumplete has an unusually well-documented origin. In 2023, London-based developer Daniel Tait asked ChatGPT to invent a logic puzzle similar to Sudoku that did not already exist, then had the AI write a playable HTML and JavaScript version, which he polished into the public site. The story became widely covered, partly because the concept turned out to closely resemble earlier mobile games such as Summer, which had been on app stores since around 2020. That history is a genuine part of why people remember Sumplete: it is often cited as one of the first popular browser games whose first draft was generated by a chatbot.

The daily side of Sumplete is split into a Daily 5x5 and a harder Daily 7x7, each a fresh puzzle that changes every day and is meant to be solved as quickly as you can. A free account lets you save win streaks, track your solve times, and reach the full archive, so missed days and older puzzles stay playable across grid sizes. There is also an Unlimited mode that serves puzzles from 3x3 up to 9x9 at your own pace with adjustable difficulty, which makes the site work both as a quick daily ritual and as an open-ended practice ground. The vibe is quiet and methodical, friendly to anyone who likes mental math, Sudoku, or Picross, and the larger grids scale up to a genuinely demanding challenge.

How to play Sumplete

1. Look at the target sum printed at the end of each row and at the bottom of each column.
2. Click a cell once to mark it with a red cross, which removes that number from its row and column totals.
3. Click the same cell a second time to turn the red cross into a green circle, marking that number as one you want to keep.
4. Click it a third time to clear the cell back to blank, since each cell cycles blank, red cross, green circle, and blank again on successive clicks.
5. Keep crossing out and circling until the kept numbers in a row add up to that row's target, and do the same for every column, since each cell answers to both a row target and a column target.
6. Finish the grid so all targets are satisfied at once, then try the Daily 5x5, the harder Daily 7x7, or any size from 3x3 to 9x9 in Unlimited mode.

Tips and strategy

• Attack zero-target rows and columns first: every number in them must be deleted, which instantly fixes the state of the crossing cells.
• Look for any row or column whose target equals the sum of all its numbers, because then nothing can be removed and every cell is kept.
• Start with the smallest target sums, since they have the fewest combinations of numbers that can reach them and are easier to pin down.
• Use the green circle to mark cells you are sure to keep, not just the ones you delete, so a solved row or column stays locked while you work the rest.
• Cross-check row and column constraints together: a number you are forced to keep for its row still has to fit its column total, and conflicts reveal mistakes.
• Avoid clearing whole rows too early, since aggressive deletions can dead-end the board and force you to backtrack later.

Good to know

Resets

New daily puzzles every day (Daily 5x5 and Daily 7x7)

Cost

Free to play

Grid sizes

Daily 5x5 and 7x7; Unlimited mode from 3x3 to 9x9

Archive

Yes, full archive of past daily puzzles with a free account

Creator

Daniel Tait, developed in 2023 with ChatGPT

Platform

Browser-based at sumplete.com

Sumplete FAQ

Is Sumplete free?

Yes. Sumplete is free to play in a browser. A free account is optional and adds win streaks, solve-time tracking, and access to the full puzzle archive.

How do you play Sumplete?

Cross out numbers so the cells you keep in each row add up to that row's target, and the same for every column. Each cell cycles through three states on single clicks: one click marks a red cross to delete, a second click turns it into a green circle to keep, and a third click clears it. Solve so all targets match at once.

Is Sumplete related to Wordle?

No. It rides the daily-puzzle trend popularized by Wordle, but it is a math and elimination puzzle with no hidden word and no guess-limit feedback. It plays more like a reverse Sudoku.

Who created Sumplete?

London-based developer Daniel Tait built it in 2023 after asking ChatGPT to invent a Sudoku-like logic puzzle. The concept turned out to resemble earlier mobile games such as Summer, which drew wide coverage at the time.

Is there a Sumplete archive?

Yes. With a free account you can play every past daily puzzle across grid sizes and browse the archive by date, so missed days remain playable.