JSON Size Calculator

Array Size multiplies the entire character count of one object -- keys, values, and nesting overhead together -- because each additional array element repeats the whole object structure. Keys Per Object only adds more key-value pairs within a single object, so it changes a smaller share of the total. Doubling Array Size roughly doubles Total Characters; doubling Keys Per Object does not.

No -- it's an estimate, counted directly without the newlines, indentation and post-colon spaces the pretty-printed Total Characters figure includes, typically around 82% of it for typical key and value lengths. A real minifier's output depends on the actual data and formatting style, so use this figure for rough payload-size planning, not as an exact byte count.

Less than Array Size or Keys Per Object at typical values -- each nesting level adds a couple of characters of indentation to every line of every object. It compounds with Array Size, though, since every repeated object in the array carries the same nesting overhead.

It reports how many full copies of your described structure -- the whole array, as configured -- fit inside a 1 MB (1,048,576-byte) payload, and separately how many individual objects that represents (full payloads multiplied by Array Size). Earlier versions of this figure quoted only the payload count under an "Objects per 1MB" label, which undercounted the true object count by a factor of Array Size. It's meant to help size API pagination or batch limits around a target payload size.

JSON is highly repetitive text -- the same key names and syntax characters (quotes, colons, commas, braces) repeat across every object in an array -- and gzip compression is very effective at exploiting exactly that kind of repetition, typically compressing repetitive JSON to roughly 30% of its uncompressed size, well beyond what simply removing whitespace achieves. For very small payloads the estimate is floored at 20 bytes, since real gzip output always carries a fixed header-and-trailer overhead that a pure percentage would understate.