File Size Formatter API

GET

Give users clear file sizes instead of raw byte counts.

File Size Formatter converts raw byte counts into human-readable file size strings. Send a byte count with optional precision and unit settings to receive formatted labels, unit names, and scaled numeric values.

Try it — live request, no key required

Request

GETapi.apiverve.com/v1/filesizeformatter?bytes=1073741824

Query parameters

bytesinteger

Verification

Format

No key required to try it. Get a key to use it in your app.

Example

{
  "status": "ok",
  "error": null,
  "data": {
    "bytes": 1073741824,
    "formatted": "1 GiB",
    "value": 1,
    "unit": "GiB",
    "standard": "binary",
    "precision": 2,
    "conversions": {
      "B": 1073741824,
      "KiB": 1048576,
      "MiB": 1024,
      "GiB": 1,
      "TiB": 0,
      "PiB": 0,
      "EiB": 0,
      "ZiB": 0,
      "YiB": 0
    }
  }
}

About the File Size Formatter API

File Size Formatter works by dividing byte values by the appropriate divisor (1024 for binary, 1000 for decimal) to calculate sizes in various units. Automatically selects the most appropriate unit or allows manual specification.

What people use it for

File Management: Display file sizes in user-friendly formats in file managers and storage applications
Storage Analytics: Format storage usage data in dashboards and analytics reports
Data Transfer: Show download and upload sizes in appropriate units during file transfers
API Responses: Convert byte sizes to readable formats in API responses and data exports

Ways to call it

One endpoint, many ways in — REST with JSON, XML, YAML and CSV, plus GraphQL and an MCP interface for AI agents.

JSON: Default REST response
XML: Markup format
YAML: Human-readable
CSV: Tabular export
GraphQL: Query language
MCP: For AI agents

View all integrations →

Other ways to use File Size Formatter

Same data, same APIVerve account, same credit balance — one key works on all of them.

Give it to an AI agentConnect over MCP and your agent calls it as a native tool — Claude, Cursor, ChatGPT.on VerveKit Google Sheets or ExcelA =VERVE() formula fills a column — no script, no export, recalculates in place.on VerveSheets Ground an agent on itA cited, machine-checkable fact your model can't produce on its own.on VerveContext

Questions.

Common questions about the File Size Formatter API.

Read the docs →

Does it support both 1024-based binary and 1000-based decimal standards?

Yes, it supports binary calculations based on 1024 multipliers like KiB, MiB, and GiB as well as decimal standards based on 1000 multipliers like KB, MB, and GB. You can specify your preferred standard on each request.

Can I choose the target unit or customize the decimal places?

Yes, you can specify an exact target unit or omit it to let the system automatically select the cleanest unit. You can also configure precision between 0 and 10 decimal places to control rounding.

What size range does File Size Formatter support?

The API handles values starting from single bytes all the way up through yobibytes. It supports byte, kibibyte, mebibyte, gibibyte, tebibyte, pebibyte, exbibyte, zebibyte, and yobibyte tiers.

Is the multi-unit conversion table included on the Free plan?

No, the full conversions breakdown across all units is a premium feature. The Free plan returns the primary formatted string and unit value, while any paid plan unlocks the complete conversion table spanning bytes to yobibytes.

How far does the Starter plan go for file size conversions?

The Starter plan covers 100,000 conversions each month. Because each request uses 2 credits, calls work out to about $0.0003 each, or $0.30 per 1,000 calls. You can also test with 100 calls per month on the Free plan.

Request parameters — GET /v1/filesizeformatter

Sent in the query string. Premium parameters are accepted on every plan but only take effect on plans that include them. Anything not listed here is dropped rather than passed through.

Required

Parameter	Type	Example	Description
`bytes`Required	integer	`1073741824`	Number of bytes to format range 0-inf

Optional

Parameter	Type	Example	Description
`unit`Optional	string	`GB`	Specific target unit (optional, auto-selects best unit if not specified) `autoBKBMBGBTBPBEB`+2
`precision`Optional	integer	`2`	Decimal places (0-10) default 2 · range 0-10
`standard`Optional	string	`binary`	Standard to use: binary (1024) or decimal (1000) `binarydecimal` default binary

Example request

1
2

curl "https://api.apiverve.com/v1/filesizeformatter?bytes=1073741824&unit=GB&precision=2&standard=binary" \
  -H "x-api-key: YOUR_API_KEY"

Authentication

Send your key in the x-api-key header. That is the only auth step — no token exchange, and no per-endpoint scope to configure.

Header	When	Value
`x-api-key`Required	Every request	Your API key. Header names are case-insensitive, so `X-API-Key` is the same header.
`Authorization`Alternate	Instead of the above	`Bearer <key>` — for clients that only expose bearer auth. Resolves to the same account and the same billing.

401 is the only auth verdict

A 401 means the key is missing, invalid or expired. A 403 means the key is valid but not permitted here — blocked by a key restriction or an IP allow-list. Running out of credits is a 429.

Response — GET /v1/filesizeformatter

Every APIVerve endpoint returns the same three top-level keys, so one response handler covers your whole integration: status, error and data. Only data changes shape.

Sample response

{
  "status": "ok",
  "error": null,
  "data": {
    "bytes": 1073741824,
    "formatted": "1 GiB",
    "value": 1,
    "unit": "GiB",
    "standard": "binary",
    "precision": 2,
    "conversions": {
      "B": 1073741824,
      "KiB": 1048576,
      "MiB": 1024,
      "GiB": 1,
      "TiB": 0,
      "PiB": 0,
      "EiB": 0,
      "ZiB": 0,
      "YiB": 0
    }
  }
}

Response fields

Paths are relative to data. Premium fields are absent rather than zeroed on plans that do not include them, so check for presence instead of comparing to 0.

Field	Type	Example	Description
`bytes`	number	`1073741824`	Original byte value in numeric format
`formatted`	string	`"1 GiB"`	Formatted file size with unit as human-readable string
`value`	number	`1`	Numeric value in the selected or auto-determined unit
`unit`	string	`"GiB"`	File size unit used in the conversion (e.g., GiB, MB)
`standard`	string	`"binary"`	Standard used for conversion: binary or decimal
`precision`	number	`2`	Decimal places applied to the formatted value
`conversions`Premium	object	`{...}`	Complete conversion table with values across all units
`B`Premium	number	`1073741824`	The size expressed in bytes
`KiB`Premium	number	`1048576`	The size expressed in kibibytes (1024 bytes)
`MiB`Premium	number	`1024`	The size expressed in mebibytes
`GiB`Premium	number	`1`	The size expressed in gibibytes
`TiB`Premium	number	`0`	The size expressed in tebibytes
`PiB`Premium	number	`0`	The size expressed in pebibytes
`EiB`Premium	number	`0`	The size expressed in exbibytes
`ZiB`Premium	number	`0`	The size expressed in zebibytes
`YiB`Premium	number	`0`	The size expressed in yobibytes

Response headers

Every response carries your balance, so your own code always knows where it stands without polling anything. All four are exposed to browsers through CORS.

Header	What it carries
`x-api-remaining-credits`	Credits left in the current cycle
`x-api-credits-used`	Credits spent in the current cycle
`x-api-max-credits`	The allowance for the cycle
`x-api-version`	Version of the endpoint that answered

Errors

Read the HTTP status first, then error for the specific reason. The body names the parameter that has to change.

Status	Meaning	What to do
`400`	Input was rejected	Read `error`; it names the parameter that has to change.
`401`	Key missing or invalid	Check the header name and the key value.
`403`	Key valid, but not permitted here	A key restriction or an IP allow-list — never a bad key.
`429`	Rate limited, or out of credits	Read `error` to tell them apart, then back off or top up.

What a call costs — 2 credits per call

Credits are shared across every APIVerve API — one balance, one key, one bill. Failed requests never count against it, so a rejected input costs nothing.

Plan	Per month	Credits	File Size Formatter calls	Per 1,000 calls
Free	Free	200	100	Free
Starter	$29.99	200,000	100,000	$0.30
Pro	$99.99	1,000,000	500,000	$0.20
Mega	$299.99	4,000,000	2,000,000	$0.15

Calls are what the credits buy at this API's rate — spend them here, on any of the other APIs, or across both. Nothing is reserved per endpoint.

Compare all pricing tiers →

Call it from cURL — GET /v1/filesizeformatter

No SDK to install — this is a plain HTTPS call to /v1/filesizeformatter with your key in the x-api-key header. Swap in a real key and it runs as-is.

cURL

1
2

curl "https://api.apiverve.com/v1/filesizeformatter" \
  -H "x-api-key: YOUR_API_KEY"

Resources

GitHubapiverve/filesizeformatter-apiSource, issues and the examples this page is built from.ReferenceFile Size Formatter API docsEvery parameter, every response field, and the errors.ParametersWhat this call acceptsRequired and optional inputs, with example values.

Also published for

@apiverve/filesizeformatternpm APIVerve.API.FileSizeFormatterNuGet

Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.

Call it from Node.js — GET /v1/filesizeformatter

Install the Node.js SDK, then call the File Size Formatter API with your key. The client wraps the same HTTPS request, so anything it returns is what the endpoint returns.

Install — npm

npm install @apiverve/filesizeformatter

Node.js

const res = await fetch("https://api.apiverve.com/v1/filesizeformatter", {
  headers: { "x-api-key": "YOUR_API_KEY" },
});
const { data } = await res.json();
console.log(data);

Resources

npm@apiverve/filesizeformatterThe published Node.js client, versioned and signed.GitHubapiverve/filesizeformatter-apiSource, issues and the examples this page is built from.ReferenceFile Size Formatter API docsEvery parameter, every response field, and the errors.ParametersWhat this call acceptsRequired and optional inputs, with example values.

Also published for

APIVerve.API.FileSizeFormatterNuGet

Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.

Call it from Python — GET /v1/filesizeformatter

No SDK to install — this is a plain HTTPS call to /v1/filesizeformatter with your key in the x-api-key header. Swap in a real key and it runs as-is.

Python

import requests

res = requests.get(
    "https://api.apiverve.com/v1/filesizeformatter",
    headers={"x-api-key": "YOUR_API_KEY"},
)
print(res.json()["data"])

Resources

Also published for

@apiverve/filesizeformatternpm APIVerve.API.FileSizeFormatterNuGet

Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.

Call it from C# / .NET — GET /v1/filesizeformatter

Install the C# / .NET SDK, then call the File Size Formatter API with your key. The client wraps the same HTTPS request, so anything it returns is what the endpoint returns.

Install — NuGet

dotnet add package APIVerve.API.FileSizeFormatter

C# / .NET

using var client = new HttpClient();
client.DefaultRequestHeaders.Add("x-api-key", "YOUR_API_KEY");

var json = await client.GetStringAsync("https://api.apiverve.com/v1/filesizeformatter");
Console.WriteLine(json);

Resources

NuGetAPIVerve.API.FileSizeFormatterThe published C# / .NET client, versioned and signed.GitHubapiverve/filesizeformatter-apiSource, issues and the examples this page is built from.ReferenceFile Size Formatter API docsEvery parameter, every response field, and the errors.ParametersWhat this call acceptsRequired and optional inputs, with example values.

Also published for

@apiverve/filesizeformatternpm

Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.

Call it from Go — GET /v1/filesizeformatter

No SDK to install — this is a plain HTTPS call to /v1/filesizeformatter with your key in the x-api-key header. Swap in a real key and it runs as-is.

req, _ := http.NewRequest("GET", "https://api.apiverve.com/v1/filesizeformatter", nil)
req.Header.Set("x-api-key", "YOUR_API_KEY")

res, _ := http.DefaultClient.Do(req)
defer res.Body.Close()
body, _ := io.ReadAll(res.Body)
fmt.Println(string(body))

Resources

Also published for

@apiverve/filesizeformatternpm APIVerve.API.FileSizeFormatterNuGet

Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.

Call it from PHP — GET /v1/filesizeformatter

No SDK to install — this is a plain HTTPS call to /v1/filesizeformatter with your key in the x-api-key header. Swap in a real key and it runs as-is.

PHP

$ch = curl_init("https://api.apiverve.com/v1/filesizeformatter");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, ["x-api-key: YOUR_API_KEY"]);

$response = curl_exec($ch);
echo $response;

Resources

Also published for

@apiverve/filesizeformatternpm APIVerve.API.FileSizeFormatterNuGet

Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.

Call it from Ruby — GET /v1/filesizeformatter

No SDK to install — this is a plain HTTPS call to /v1/filesizeformatter with your key in the x-api-key header. Swap in a real key and it runs as-is.

Ruby

require "net/http"

uri = URI("https://api.apiverve.com/v1/filesizeformatter")
req = Net::HTTP::Get.new(uri)
req["x-api-key"] = "YOUR_API_KEY"

res = Net::HTTP.start(uri.hostname, uri.port, use_ssl: true) { |h| h.request(req) }
puts res.body

Resources

Also published for

@apiverve/filesizeformatternpm APIVerve.API.FileSizeFormatterNuGet

Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.

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File Size Formatter API

Try it — live request, no key required

About the File Size Formatter API

What people use it for

Ways to call it

Other ways to use File Size Formatter

Questions.

Request parameters — GET /v1/filesizeformatter

Required

Optional

Authentication

Response — GET /v1/filesizeformatter

Response fields

Response headers

Errors

What a call costs — 2 credits per call

Call it from cURL — GET /v1/filesizeformatter

Resources

Also published for

Call it from Node.js — GET /v1/filesizeformatter

Resources

Also published for

Call it from Python — GET /v1/filesizeformatter

Resources

Also published for

Call it from C# / .NET — GET /v1/filesizeformatter

Resources

Also published for

Call it from Go — GET /v1/filesizeformatter

Resources

Also published for

Call it from PHP — GET /v1/filesizeformatter

Resources

Also published for

Call it from Ruby — GET /v1/filesizeformatter

Resources

Also published for

Zero-code embed — one snippet, no backend

Changelog — File Size Formatter API

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