Income Tax Calculator

Overview

Income Tax Calculator works by applying the official federal income tax brackets to your gross income after the standard deduction. It calculates the tax owed at each bracket level and returns a detailed breakdown including effective and marginal tax rates.

Endpoint

One host, one path per API. The block below shows this call in four languages; every one of them is the same HTTP request. Making requests covers the timeouts, retries and parameter rules that apply to all of them. The SDKs wrap the same call in a typed client.

curl "https://api.apiverve.com/v1/incometaxcalculator?income=85000&rate=22&deduction=14600" \
  -H "x-api-key: your_api_key_here"

const res = await fetch('https://api.apiverve.com/v1/incometaxcalculator?income=85000&rate=22&deduction=14600', {
  headers: { 'x-api-key': 'your_api_key_here' },
});

if (!res.ok) throw new Error(`${res.status} ${await res.text()}`);

const { data } = await res.json();
console.log(data);

import requests

res = requests.get(
    "https://api.apiverve.com/v1/incometaxcalculator?income=85000&rate=22&deduction=14600",
    headers={"x-api-key": "your_api_key_here"},
    timeout=15,
)
res.raise_for_status()

print(res.json()["data"])

package main

import (
	"fmt"
	"io"
	"net/http"
)

func main() {
	req, _ := http.NewRequest("GET", "https://api.apiverve.com/v1/incometaxcalculator?income=85000&rate=22&deduction=14600", nil)
	req.Header.Set("x-api-key", "your_api_key_here")

	res, err := http.DefaultClient.Do(req)
	if err != nil {
		panic(err)
	}
	defer res.Body.Close()

	out, _ := io.ReadAll(res.Body)
	fmt.Println(string(out))
}

Replace your_api_key_here with the key from your dashboard. When the inputs arrive as a list rather than one at a time, batch requests run up to 200 of them through this same API in a single call.

Authentication

Send your key in the x-api-key header. That is the only auth step — there is no token exchange and no per-endpoint scope to configure. Authentication covers creating, rotating and revoking keys.

Parameters

Sent in the query string. Premium parameters are accepted on every plan but only take effect on plans that include them.

Response

Every API returns the same three top-level keys, so one response handler covers your whole integration: status, error and data. Only data changes shape. Response format covers the envelope, the other output formats and how premium fields are withheld.

{
  "status": "ok",
  "error": null,
  "data": {
    "year": 2025,
    "filing_status": "single",
    "income": 85000,
    "standardDeduction": 15000,
    "taxableIncome": 70000,
    "totalTax": 10852.5,
    "effectiveRate": "12.77%",
    "marginalRate": "22%",
    "incomeAfterTax": 74147.5,
    "monthlyTax": 904.38,
    "monthlyIncome": 6178.96,
    "brackets": [
      {
        "rate": 0.1,
        "ratePercent": "10.0%",
        "rangeMin": 0,
        "rangeMax": 11925,
        "taxableAmount": 11926,
        "taxAmount": 1192.6
      },
      {
        "rate": 0.12,
        "ratePercent": "12.0%",
        "rangeMin": 11926,
        "rangeMax": 48475,
        "taxableAmount": 36550,
        "taxAmount": 4386
      },
      {
        "rate": 0.22,
        "ratePercent": "22.0%",
        "rangeMin": 48476,
        "rangeMax": 103350,
        "taxableAmount": 21524,
        "taxAmount": 4735.28
      }
    ]
  }
}

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.

Errors

Read the HTTP status first, then error for the specific reason. The body names the parameter that has to change. Error handling covers the full status list and which of them are worth retrying.

Use cases

Tax Estimation

Use the Income Tax Calculator API to estimate your federal income tax liability based on your income and filing status

Payroll Systems

Integrate the Income Tax Calculator API into payroll systems to estimate employee federal tax withholding

Financial Planning

Use the Income Tax Calculator API to compare tax liability across different income scenarios or filing statuses for financial planning

Tax Education

Build educational tools that show users how progressive tax brackets work with a detailed bracket-by-bracket breakdown

Other ways to use Income Tax Calculator

Set up Income Tax Calculator on APIVerve, or reach the same source a different way. Your APIVerve account and credits work on all of them — one key, one balance.

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