Aspect ratio calculator API

Enter a width and height to get the simplified ratio, or lock a ratio and change one side to get the other. Each result lists the Instagram, Facebook, LinkedIn, X and other image sizes with the same ratio.

• Endpoint: POST https://postboost.co/app/api/tools/aspect-ratio-calculator (operationId calculateAspectRatio)
• Web tool: postboost.co/tools/aspect-ratio-calculator
• Token: optional (limits)
• MCP: tool calculate-aspect-ratio on https://postboost.co/mcp/tools

Request

Field	Type	Default	Description
width	integer		Width in pixels.
height	integer		Height in pixels.
ratio	string		Ratio as width:height, e.g. 16:9 or 1.91:1. Give it with width or height to get the other side.

Call it

curl

curl -X POST https://postboost.co/app/api/tools/aspect-ratio-calculator \
  -H 'Content-Type: application/json' \
  -d '{"width":1080,"height":1350}'

Python

from postboost import ApiClient, Configuration
from postboost.api.free_tools_api import FreeToolsApi
from postboost.models import FreeToolCalculateAspectRatioRequest

with ApiClient(Configuration()) as client:
    api = FreeToolsApi(client)
    result = api.calculate_aspect_ratio(FreeToolCalculateAspectRatioRequest.from_dict({"width": 1080, "height": 1350}))
    print(result.to_dict())

Node.js

import { FreeToolsApi } from 'postboost';

const api = new FreeToolsApi();
const { body } = await api.calculateAspectRatio({ width: 1080, height: 1350 });
console.log(body);

PHP

use PostBoostClient\Api\FreeToolsApi;
use PostBoostClient\Model\FreeToolCalculateAspectRatioRequest;

$api = new FreeToolsApi(new GuzzleHttp\Client());
$result = $api->calculateAspectRatio(new FreeToolCalculateAspectRatioRequest(['width' => 1080, 'height' => 1350]));
echo $result;

Go

import (
    "context"
    "encoding/json"
    "fmt"

    postboost "github.com/postboost-co/postboost-go"
)

var request postboost.FreeToolCalculateAspectRatioRequest
if err := json.Unmarshal([]byte(`{"width":1080,"height":1350}`), &request); err != nil {
    panic(err)
}

client := postboost.NewAPIClient(postboost.NewConfiguration())
result, _, err := client.FreeToolsAPI.CalculateAspectRatio(context.Background()).FreeToolCalculateAspectRatioRequest(request).Execute()
fmt.Println(result, err)

Ruby

require 'postboost'

api = PostBoost::FreeToolsApi.new
result = api.calculate_aspect_ratio(PostBoost::FreeToolCalculateAspectRatioRequest.new({ width: 1080, height: 1350 }))
puts result.to_hash

Java

import com.postboost.ApiClient;
import com.postboost.api.FreeToolsApi;
import com.postboost.model.FreeToolCalculateAspectRatioRequest;
import com.postboost.model.FreeToolCalculateAspectRatioResponse;

FreeToolsApi api = new FreeToolsApi(new ApiClient());
FreeToolCalculateAspectRatioRequest request = FreeToolCalculateAspectRatioRequest.fromJson("{\"width\":1080,\"height\":1350}");
FreeToolCalculateAspectRatioResponse result = api.calculateAspectRatio(request);
System.out.println(result.toJson());

C#

using Newtonsoft.Json;
using PostBoost.Client.Api;
using PostBoost.Client.Client;
using PostBoost.Client.Model;

var api = new FreeToolsApi(new Configuration());
var request = JsonConvert.DeserializeObject<FreeToolCalculateAspectRatioRequest>(@"{""width"":1080,""height"":1350}");
var result = await api.CalculateAspectRatioAsync(request);
Console.WriteLine(result.ToJson());

Rust

use postboost::apis::configuration::Configuration;
use postboost::apis::free_tools_api;
use postboost::models::FreeToolCalculateAspectRatioRequest;

let config = Configuration::new();
let request: FreeToolCalculateAspectRatioRequest = serde_json::from_str(r##"{"width":1080,"height":1350}"##)?;
let result = free_tools_api::calculate_aspect_ratio(&config, request).await?;
println!("{:?}", result);

CLI

echo '{"width":1080,"height":1350}' | ./postboost-cli --content-type application/json calculateAspectRatio -

With a token, send Authorization: Bearer YOUR_API_TOKEN as a default header (how, per SDK).

Response

{
    "ratio": "4:5",
    "decimal": 0.8,
    "width": 1080,
    "height": 1350,
    "rounding": null,
    "orientation": "portrait",
    "matches": [
        {
            "network": "instagram",
            "format": "feed-portrait",
            "width": 1080,
            "height": 1350,
            "ratio": "4:5",
            "exact": true
        },
        {
            "network": "facebook",
            "format": "feed-image",
            "width": 1080,
            "height": 1350,
            "ratio": "4:5",
            "exact": true
        },
        {
            "network": "linkedin",
            "format": "single-image-post-vertical",
            "width": 720,
            "height": 900,
            "ratio": "4:5",
            "exact": true
        },
        {
            "network": "threads",
            "format": "post",
            "width": 1080,
            "height": 1350,
            "ratio": "4:5",
            "exact": true
        }
    ]
}

With MCP

Connect https://postboost.co/mcp/tools (setup) and ask, for example: Calculate an aspect ratio, or the missing side of an image at a given ratio with the PostBoost calculate-aspect-ratio tool.

Errors

Status	When
401	The Authorization header holds an invalid token. Leave it out to call as a guest.
413	The JSON body is larger than 128 KB.
422	A field is invalid; the body lists the errors per field.
429	A limit is reached; see limits.