Now on iOS

Add up the right numbers.

CrossSum is a cozy cross-sum puzzle. Circle the cells that belong — get every row and every column to match its total. No clutter, no timers, just numbers that click into place.

15
9
16
9
3
8
6
4

How it works

Four rules. No instructions needed.

CrossSum plays like a cross between Kakuro and a logic puzzle — every cell either belongs to the solution or it doesn't.

1

Read the headings

Every row and column has a target number above and to the left of the grid.

2

Pen or erase

Circle the digits that belong, or cross out the ones that don't — you decide the mode.

3

Watch the totals

Each heading shows a live running total as you circle, so you always know how close you are.

4

Solve every line

Get every row and column to match exactly, and the level clears — three hearts, no pressure.

Features

Small game, thoughtfully made.

Every puzzle is generated fresh and verified to have exactly one logical solution — never a guess.

Endless levels

Grids grow from 3×3 to 6×6 as you climb — a fresh, uniquely-solvable puzzle every time.

Three hearts

A wrong tap costs a heart, not the level. Miss all three and you simply try again.

💡

Hints when stuck

Two free hints to start, with more available any time you need a nudge.

Picks up where you left off

Close the app mid-puzzle and come back to the exact same board, hearts and all.

◻︎

Plain and calm

A light, clutter-free board with soft grid lines — nothing fighting for your attention.

Always fair

Every generated puzzle is checked to have one unique answer before it ever reaches you.

Numbers that click into place.

CrossSum is free to play, with optional extras if you want them.