Touch target size checker

It defaults to a 44 by 44 point target, a widely used mobile design reference, while allowing another threshold and unit for the rule your team follows. The result identifies each passing dimension, the overall outcome, and the exact shortfall that needs to be corrected.

Measure the interactive target, not just its visible icon

Touch accessibility is about the area that responds to a tap. A small icon may sit inside a comfortably padded button, so measuring only the artwork can make a good control appear to fail. The reverse is also possible: an icon can look large while its clickable element occupies a smaller box. Inspect the rendered interactive element and enter that element's width and height. Keep all four size values in the same unit. The checker defaults to points and a 44 by 44 minimum, but it does not silently convert points, pixels, density-independent pixels, or millimeters because those units depend on the design and runtime context. The unit is recorded in the result so that reports remain understandable. Width and height must both be positive, finite numbers. Zero, negative values, missing dimensions, text values, and non-finite numbers are rejected instead of producing a misleading accessibility decision. This makes the output suitable for manual reviews, design-system checks, and deterministic automated tests.

Interpret the dimension checks and shortfalls

A touch target passes only when both dimensions meet or exceed their corresponding minimums. The response separates width_passes and height_passes because a wide but short control still needs attention, even if its total area seems generous. meets_minimum is true only when both flags are true. When a dimension fails, its shortfall reports exactly how much must be added in the selected unit; a passing dimension has a shortfall of zero. For example, a target measuring 40 by 52 points against a 44 by 44 minimum fails overall: its height passes, its width does not, and width_shortfall is 4. Equality counts as a pass, so 44 by 44 meets the default threshold exactly. The calculation compares dimensions independently rather than treating an equal-area rectangle as equivalent to a square. That distinction matters for touch use, because a very narrow or very shallow target remains difficult to acquire even when its area is numerically large. No rounding is applied, so decimal measurements and custom minimums retain the precision supplied by the caller.

Choose the minimum that matches your standard

Different design systems and accessibility criteria publish different target sizes, and similar-looking units are not automatically interchangeable. Use the default 44 by 44 points when that is the rule you are checking. If your product specifies another target, provide minimum_width and minimum_height explicitly, in the same unit as the measured element. For example, a team testing a 48 by 48 density-independent-pixel convention can set both minimums to 48 and select dp. A web audit can select px and enter the CSS-pixel threshold required by its chosen criterion. The checker reports a geometric comparison; it does not claim that one default proves compliance with every accessibility standard, and it does not evaluate spacing exceptions, overlapping targets, zoom behavior, gesture alternatives, or the size of nearby controls. Those concerns require layout and interaction review. Use this result as a focused, reproducible check within that broader process. Because the algorithm uses no network, clock, randomness, or device lookup, the same input always produces the same output in the browser and through the API.