diff --git a/day3/data.txt b/day3/data.txt
new file mode 100644
index 0000000..4cb1d1c
--- /dev/null
+++ b/day3/data.txt
@@ -0,0 +1,140 @@
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diff --git a/day3/lib.zig b/day3/lib.zig
new file mode 100644
index 0000000..941df5f
--- /dev/null
+++ b/day3/lib.zig
@@ -0,0 +1,12 @@
+const std = @import("std");
+
+pub fn splitArrayIntoArrayList(content: []const u8, char: *const [1:0]u8) !std.ArrayList([]const u8) {
+    const allocator = std.heap.page_allocator;
+    var grid = std.ArrayList([]const u8).init(allocator);
+    var lines = std.mem.split(u8, content, char);
+
+    while (lines.next()) |line| {
+        try grid.append(line);
+    }
+    return grid;
+}
diff --git a/day3/main.zig b/day3/main.zig
new file mode 100644
index 0000000..bebfce4
--- /dev/null
+++ b/day3/main.zig
@@ -0,0 +1,111 @@
+const std = @import("std");
+const lib = @import("lib.zig");
+
+const Number = struct { row: usize, col: usize, length: usize, value: u32 };
+
+pub fn main() !void {
+    const content = @embedFile("data.txt");
+    const grid = try lib.splitArrayIntoArrayList(content, "\n");
+    defer grid.deinit();
+
+    const numbers = try parseNumbers(grid);
+
+    var total1: u128 = 0;
+
+    for (numbers.items) |n| {
+        if (numberTouchesSymbol(n, grid)) {
+            total1 += n.value;
+        }
+    }
+
+    std.debug.print("total1 {d}\n", .{total1});
+
+    var total2: u128 = 0;
+    for (grid.items, 0..) |line, row| {
+        for (line, 0..) |val, col| {
+            if (val == '*') {
+                total2 += try findGearRatio(row, col, numbers);
+            }
+        }
+    }
+    std.debug.print("total2 {d}\n", .{total2});
+}
+
+fn findGearRatio(row: usize, col: usize, numbers: std.ArrayList(Number)) !u32 {
+    const touching = try findNumbersTouchingCell(row, col, numbers);
+    if (touching.items.len != 2) {
+        return 0;
+    }
+    return touching.items[0].value * touching.items[1].value;
+}
+
+fn findNumbersTouchingCell(row: usize, col: usize, numbers: std.ArrayList(Number)) !std.ArrayList(Number) {
+    const allocator = std.heap.page_allocator;
+    var touching = std.ArrayList(Number).init(allocator);
+
+    for (numbers.items) |n| {
+        // itreate over each digit in the number
+        for (0..n.length) |i| {
+            // TODO: upgrade to Zig .12 to get @abs
+            // if (@abs(n.row - row) < 1 and @abs(n.col + i - col) < 1) {
+            if ((n.row == row or n.row + 1 == row or n.row == row + 1) and (n.col + i == col or n.col + 1 + i == col or n.col + i == col + 1)) {
+                try touching.append(n);
+                break;
+            }
+        }
+    }
+    return touching;
+}
+
+fn numberTouchesSymbol(n: Number, grid: std.ArrayList([]const u8)) bool {
+    const items = grid.items;
+    const width = items[0].len;
+    const height = items.len - 1; // TODO: fix extra crap when i read files..
+
+    // itreate over each digit in the number
+    for (0..n.length) |i| {
+        // over the 3 nearest rows
+        for (0..3) |r| {
+            // and the 3 nearest columns
+            for (0..3) |c| {
+                const outOfBounds = (r == 0 and n.row == 0) or (c == 0 and n.col + i == 0) or (r == 2 and n.row + 1 == height) or (c == 2 and n.col + i + 1 == width);
+
+                if (!outOfBounds) {
+                    const row = n.row + r - 1;
+                    const col = n.col + c + i - 1;
+                    const val = items[row][col];
+                    if (!std.ascii.isDigit(val) and val != '.') {
+                        return true;
+                    }
+                }
+            }
+        }
+    }
+    return false;
+}
+
+fn parseNumbers(grid: std.ArrayList([]const u8)) !std.ArrayList(Number) {
+    const allocator = std.heap.page_allocator;
+    var numbers = std.ArrayList(Number).init(allocator);
+
+    for (grid.items, 0..) |line, row| {
+        var numList = std.ArrayList(u8).init(allocator);
+        defer numList.deinit();
+
+        for (line, 0..) |val, col| {
+            if (std.ascii.isDigit(val)) {
+                try numList.append(val);
+            }
+
+            // if we have a number started, and we've encountered a non-digit (or the end of the grid)
+            if (numList.items.len != 0 and (!std.ascii.isDigit(val) or col == line.len - 1)) {
+                const parsed = try std.fmt.parseInt(u32, numList.items, 10);
+                const length = numList.items.len;
+                try numbers.append(Number{ .row = row, .col = col - length, .length = length, .value = parsed });
+                numList.items.len = 0;
+            }
+        }
+    }
+
+    return numbers;
+}
diff --git a/day3/test.txt b/day3/test.txt
new file mode 100644
index 0000000..b20187f
--- /dev/null
+++ b/day3/test.txt
@@ -0,0 +1,10 @@
+467..114..
+...*......
+..35..633.
+......#...
+617*......
+.....+.58.
+..592.....
+......755.
+...$.*....
+.664.598..