JSON byte size calculator

Client

Check how large a JSON document is in UTF-8 bytes—useful for API payload limits, CDN caches, and mobile bandwidth. See minified vs formatted sizes without uploading data.

Root type
object
Input characters
150
Input UTF-8 bytes
153
Minified UTF-8 bytes
121
Pretty UTF-8 bytes
185
Lines in input
7

Nearby workflows on Toolcore

  • JSON formatter — JSON format online: pretty-print, minify, validate, escape, download . once JSON text parses on this page.
  • JSON statistics — Depth, key counts, object/array totals, and value-type breakdown—local only. once JSON text parses on this page.
  • JSON minify — Minify JSON to a compact single-line string—local. once JSON text parses on this page.
  • JSON canonicalization (JCS) — RFC 8785 JCS: deterministic canonical JSON string and SHA-256—signing and hashing, client-side. once JSON text parses on this page.

Common use cases

  • Estimate whether a REST response fits a gateway or Lambda payload cap.
  • Compare minified vs pretty JSON before storing in a KV or log stream.
  • Sanity-check unicode-heavy strings (emoji, accented text) for byte growth.

Common mistakes to avoid

  • Confusing characters with UTF-8 bytes

    Non-ASCII text uses more than one byte per character in UTF-8. Use the byte columns for wire size.

FAQ

Is data uploaded?

No. Size is computed locally from your paste.

Common search terms

Phrases people search for that match this tool. See the full long-tail keyword index.

  • json byte size calculator
  • json utf-8 size
  • measure json payload size
  • json file size in bytes

More tools

Related utilities you can open in another tab—mostly client-side.