Calculator API — 135+ Online Calculators | YEB

135+ online calculators via REST API. Finance, health, math, construction, physics and more. Evaluate formulas, search calculators, get definitions.

API FAQ

Dapatkan Kunci API Beli Kredit

Try it live

All 135 calculators are available for free on the web app:

Open calculator.yeb.to

✓

135+ calculators
Finance, health, math, construction, physics, chemistry, biology, statistics, and more.

✓

16 categories
Organized by topic for easy discovery and integration.

✓

30 languages
Translated titles, descriptions, and input/output labels.

Endpoint:

99.9 % Masa Aktif

7ms Respons

20 req/s

0.001 Kredit / permintaan

Calculate


POST https://api.yeb.to/v1/calculator/calculate

Parameter	Jenis	Wajib	Penerangan
`api_key`	string	ya	Your API key
`calculator_id`	integer	ya	ID of the calculator to evaluate
`inputs`	object	ya	Input values as key-value pairs (e.g. {"length": 10, "width": 5})
`units`	object	pilihan	Selected units per input/output (e.g. {"length": "m", "area": "m2"})

Contoh

curl -X POST https://api.yeb.to/v1/calculator/calculate \
  -H "Content-Type: application/json" \
  -d '{
  "api_key": "YOUR_KEY",
  "calculator_id": 1,
  "inputs": {
    "value": 200,
    "percentage": 15
  },
  "units": {}
}'

Contoh Respons

{
  "calculator_id": 1,
  "calculator_slug": "percentage",
  "results": {
    "result": {
      "value": 30,
      "unit": null
    },
    "inverse": {
      "value": 7.5,
      "unit": null
    }
  },
  "credits_spent": 0.001,
  "credits_left": 99.99,
  "response_code": 200,
  "response_time_ms": 12
}

{
  "error": "Calculator not found",
  "response_code": 404,
  "response_time_ms": 3
}

Kod Respons

Kod	Penerangan
200 Success	Permintaan diproses OK.
400 Bad Request	Pengesahan input gagal.
401 Unauthorized	Kunci API hilang / salah.
403 Forbidden	Kunci tidak aktif atau tidak dibenarkan.
429 Rate Limit	Terlalu banyak permintaan.
500 Server Error	Kegagalan tidak dijangka.

Calculate

calculator/calculate 0.0010 credits

Method

URL

Authentication

API Key

Parameters

API Key

body · string · required

Calculator ID

body · string · required

Inputs

body · string · required

Units

body · string

Code Samples

Response

Status: —

Headers

Body

List Calculators


POST https://api.yeb.to/v1/calculator/list

Parameter	Jenis	Wajib	Penerangan
`api_key`	string	ya	Your API key
`category`	string	pilihan	Filter by category slug (e.g. "finance", "health", "math")
`locale`	string	pilihan	Language code for translated titles (default: en)
`limit`	integer	pilihan	Max results, 1–100 (default: 50)
`offset`	integer	pilihan	Skip N results for pagination (default: 0)

Contoh

curl -X POST https://api.yeb.to/v1/calculator/list \
  -H "Content-Type: application/json" \
  -d '{
  "api_key": "YOUR_KEY",
  "category": "finance",
  "locale": "en",
  "limit": 5
}'

Contoh Respons

{
  "total": 14,
  "offset": 0,
  "limit": 5,
  "calculators": [
    {
      "id": 1,
      "slug": "percentage",
      "title": "Percentage Calculator",
      "short_description": "Calculate what X% of Y is.",
      "category": "finance"
    },
    {
      "id": 2,
      "slug": "percentage-change",
      "title": "Percentage Change Calculator",
      "short_description": "Calculate percentage change between two values.",
      "category": "finance"
    }
  ],
  "credits_spent": 0,
  "credits_left": 100,
  "response_code": 200,
  "response_time_ms": 8
}

{
  "error": "Invalid limit parameter",
  "response_code": 400,
  "response_time_ms": 2
}

Kod Respons

Kod	Penerangan
200 Success	Permintaan diproses OK.
400 Bad Request	Pengesahan input gagal.
401 Unauthorized	Kunci API hilang / salah.
403 Forbidden	Kunci tidak aktif atau tidak dibenarkan.
429 Rate Limit	Terlalu banyak permintaan.
500 Server Error	Kegagalan tidak dijangka.

List Calculators

calculator/list 0.0000 credits

Method

URL

Authentication

API Key

Parameters

API Key

body · string · required

Code Samples

Response

Status: —

Headers

Body

Calculator Info


POST https://api.yeb.to/v1/calculator/info

Parameter	Jenis	Wajib	Penerangan
`api_key`	string	ya	Your API key
`slug`	string	pilihan	Calculator slug (e.g. "bmi", "mortgage")
`calculator_id`	integer	pilihan	Calculator ID (alternative to slug)
`locale`	string	pilihan	Language code (default: en)

Contoh

curl -X POST https://api.yeb.to/v1/calculator/info \
  -H "Content-Type: application/json" \
  -d '{
  "api_key": "YOUR_KEY",
  "slug": "bmi"
}'

Contoh Respons

{
  "id": 25,
  "slug": "bmi",
  "title": "BMI Calculator",
  "short_description": "Calculate your Body Mass Index.",
  "formula": {
    "inputs": [
      {"key": "weight", "type": "number", "default": 70, "unit_group": "mass", "default_unit": "kg"},
      {"key": "height", "type": "number", "default": 175, "unit_group": "height", "default_unit": "cm"}
    ],
    "outputs": [
      {"key": "bmi", "expression": "weight / (height * height)", "precision": 1},
      {"key": "category", "expression": "..."}
    ],
    "unit_groups": {
      "mass": {"kg": 1, "lb": 0.453592},
      "height": {"m": 1, "cm": 0.01, "in": 0.0254}
    }
  },
  "input_labels": {"weight": "Weight", "height": "Height"},
  "output_labels": {"bmi": "Your BMI", "category": "Category"},
  "category": {"slug": "health", "name": "Health & Fitness"},
  "credits_spent": 0,
  "response_code": 200
}

{
  "error": "Calculator not found",
  "response_code": 404,
  "response_time_ms": 3
}

Kod Respons

Kod	Penerangan
200 Success	Permintaan diproses OK.
400 Bad Request	Pengesahan input gagal.
401 Unauthorized	Kunci API hilang / salah.
403 Forbidden	Kunci tidak aktif atau tidak dibenarkan.
429 Rate Limit	Terlalu banyak permintaan.
500 Server Error	Kegagalan tidak dijangka.

Calculator Info

calculator/info 0.0000 credits

Method

URL

Authentication

API Key

Parameters

API Key

body · string · required

Slug

body · string

Calculator ID

body · string

Locale

body · string

Code Samples

Response

Status: —

Headers

Body

Search Calculators


POST https://api.yeb.to/v1/calculator/search

Parameter	Jenis	Wajib	Penerangan
`api_key`	string	ya	Your API key
`query`	string	ya	Search query (minimum 2 characters)
`locale`	string	pilihan	Language code (default: en)
`limit`	integer	pilihan	Max results, 1–50 (default: 20)

Contoh

curl -X POST https://api.yeb.to/v1/calculator/search \
  -H "Content-Type: application/json" \
  -d '{
  "api_key": "YOUR_KEY",
  "query": "mortgage",
  "locale": "en",
  "limit": 5
}'

Contoh Respons

{
  "query": "mortgage",
  "results": [
    {
      "id": 5,
      "slug": "mortgage",
      "title": "Mortgage Calculator",
      "short_description": "Calculate monthly mortgage payment, total interest, and total amount paid.",
      "category": "finance"
    },
    {
      "id": 9,
      "slug": "amortization",
      "title": "Amortization Calculator",
      "short_description": "See how each payment splits between principal and interest.",
      "category": "finance"
    }
  ],
  "credits_spent": 0,
  "response_code": 200,
  "response_time_ms": 15
}

{
  "error": "Query must be at least 2 characters",
  "response_code": 400,
  "response_time_ms": 2
}

Kod Respons

Kod	Penerangan
200 Success	Permintaan diproses OK.
400 Bad Request	Pengesahan input gagal.
401 Unauthorized	Kunci API hilang / salah.
403 Forbidden	Kunci tidak aktif atau tidak dibenarkan.
429 Rate Limit	Terlalu banyak permintaan.
500 Server Error	Kegagalan tidak dijangka.

Search Calculators

calculator/search 0.0000 credits

Method

URL

Authentication

API Key

Parameters

API Key

body · string · required

Query

body · string · required

Locale

body · string

Limit

body · string

Code Samples

Response

Status: —

Headers

Body

Calculator API — 135+ Online Calculators | YEB — Practical Guide

A hands-on guide to the Calculator API: 135+ online calculators across 16 categories, formula evaluation with unit conversion, multilingual support in 30 languages, and how to integrate it all into your application.

Last updated: 21 Mac 2026, 00:21 API Version: v1 Burst: 20 req/s Latency: 7 ms

#What the Calculator API does

The Calculator API provides 4 endpoints for accessing 135+ online calculators: evaluate formulas with unit conversion, list and search calculators, and get complete formula definitions — all via simple POST requests.

Key advantage: three out of four endpoints are completely free. Only the Calculate endpoint costs credits (0.001 per request). Formula definitions are open, so you can also evaluate client-side if preferred.

#Endpoints at a glance

Endpoint	What it does	Credits
`POST /v1/calculator/calculate`	Evaluate a calculator formula with inputs and unit conversion	0.001
`POST /v1/calculator/list`	List all calculators, optionally filtered by category	FREE
`POST /v1/calculator/info`	Get full formula definition, inputs, outputs, and unit groups	FREE
`POST /v1/calculator/search`	Search calculators by keyword across all categories	FREE

#Available categories

135 calculators are organized into 16 categories:

Category	Slug	Count	Examples
Finance	`finance`	14	Percentage, Mortgage, Compound Interest, ROI, CAGR
Salary & Tax	`salary-tax`	10	Gross/Net, VAT, Tip, Discount, Margin, Retirement
Health & Fitness	`health`	12	BMI, Calories (TDEE), BMR, Body Fat, Protein
Pregnancy	`pregnancy`	5	Due Date, Ovulation, Period, Fertility Window
Math	`math`	10	Fraction, Quadratic Formula, GPA, Logarithm
Conversion	`conversion`	10	Weight, Length, Temperature, Speed, Pressure
Time & Date	`time-date`	7	Age, Days Between Dates, Countdown, Time Zone
Construction	`construction`	9	Concrete, Brick, Tile, Paint, Roofing
Automotive	`automotive`	8	Fuel Cost, Tire Size, Horsepower, 0-100 km/h
Physics	`physics`	8	Free Fall, Force, Kinetic Energy, Projectile Motion
Chemistry	`chemistry`	7	Molar Mass, pH, Dilution, Percent Yield
Biology	`biology`	6	Punnett Square, DNA, Bacteria Growth
Statistics	`statistics`	8	Std Deviation, Confidence Interval, Z-Score
Food & Cooking	`food`	8	Pizza, Coffee, Grams to Cups, Recipe Scaler
Sports	`sports`	7	Calories Burned, Pace, Marathon, VO2 Max
Fun & Viral	`fun`	6	Love Compatibility, Lucky Number, Zodiac

#How the formula system works

Each calculator stores its formula as a JSON definition with inputs, outputs, unit groups, and constants. The formula engine supports arithmetic, ternary expressions, and built-in math functions (sqrt, sin, cos, log, pow, min, max, etc.).

Use the info endpoint to retrieve the complete formula definition for any calculator. You can then evaluate it server-side via the calculate endpoint, or implement client-side evaluation using the same expression language.

Unit conversion is automatic. Define unit groups (e.g. length: m, cm, ft, in) with conversion factors. Inputs are normalized to base units before evaluation, and outputs are converted to the user's selected display unit.

#Multilingual support

All 135 calculators are translated into 30 languages: English, Bulgarian, Spanish, German, French, Italian, Portuguese, Russian, Polish, Dutch, Turkish, Czech, Romanian, Hungarian, Ukrainian, Swedish, Danish, Finnish, Norwegian, Greek, Arabic, Hebrew, Japanese, Korean, Chinese (Simplified & Traditional), Thai, Vietnamese, Indonesian, and Malay.

Use the locale parameter on the list, info, and search endpoints to get translated titles, descriptions, input/output labels, and educational content.

#Common use cases

Embedded calculators — add interactive calculators to your website or app
Education platforms — provide step-by-step calculations for students
Health & fitness apps — BMI, calorie, and body composition calculations
Real estate tools — mortgage, loan, and amortization calculations
Construction estimators — material quantity and cost calculators
Chatbots & AI assistants — answer calculation questions programmatically
Comparison tools — evaluate multiple scenarios with different inputs

#Try it live

All 135 calculators are available for free on calculator.yeb.to. Each calculator has an interactive widget, educational article, FAQ section, and SEO-optimized pages in 30 languages. The web app uses the same formula engine as the API.

Soalan Lazim

135+ calculators across 16 categories: finance (percentage, mortgage, compound interest, ROI), health (BMI, calories, body fat), math (quadratic formula, logarithm), construction (concrete, brick, tile), physics (free fall, kinetic energy), chemistry (molar mass, pH), and more.

The Calculate endpoint costs 0.001 credits per request. List, Info, and Search endpoints are completely free. Sign up to get free credits.

All 135 calculators are translated into 30 languages including English, Spanish, German, French, Bulgarian, Russian, Japanese, Chinese, Arabic, and more. Use the locale parameter to get translated content.

Yes! Use the Info endpoint with a calculator slug to get the complete formula definition including inputs, outputs, expressions, unit groups, and constants. You can evaluate formulas client-side or via the Calculate endpoint.

Each calculator defines unit groups with conversion factors. When you send a units parameter with your Calculate request, inputs are automatically converted to base units before evaluation, and outputs are converted to your selected display units.

Ya. Setiap permintaan, termasuk yang menghasilkan ralat, menggunakan kredit. Kredit anda terikat kepada bilangan permintaan, tanpa mengira kejayaan atau kegagalan. Jika ralat jelas disebabkan oleh masalah platform di pihak kami, kami akan memulihkan kredit yang terjejas (tiada bayaran balik tunai).

Hubungi kami di [email protected]. Kami mengambil maklum balas dengan serius—jika laporan pepijat atau permintaan ciri anda bermakna, kami boleh memperbaiki atau menambah baik API dengan cepat dan memberikan anda 50 kredit percuma sebagai penghargaan.

Ia bergantung pada API dan kadangkala pada endpoint. Sesetengah endpoint menggunakan data dari sumber luaran, yang mungkin mempunyai had yang lebih ketat. Kami juga menguatkuasakan had untuk mencegah penyalahgunaan dan mengekalkan kestabilan platform kami. Semak dokumentasi untuk had khusus setiap endpoint.

Kami beroperasi dengan sistem kredit. Kredit ialah unit prabayar yang tidak boleh dikembalikan yang anda belanjakan untuk panggilan API dan alatan. Kredit digunakan secara FIFO (yang paling lama dahulu) dan sah selama 12 bulan dari tarikh pembelian. Papan pemuka menunjukkan setiap tarikh pembelian dan tamat tempohnya.

Ya. Semua kredit yang dibeli (termasuk baki pecahan) sah selama 12 bulan dari pembelian. Kredit yang tidak digunakan tamat tempoh secara automatik dan dipadam secara kekal pada akhir tempoh sah. Kredit yang tamat tempoh tidak boleh dipulihkan atau ditukar kepada tunai atau nilai lain. Peraturan peralihan: kredit yang dibeli sebelum 22 Sep 2025 dianggap dibeli pada 22 Sep 2025 dan tamat tempoh pada 22 Sep 2026 (melainkan tamat tempoh lebih awal dinyatakan semasa pembelian).

Ya—dalam tempoh sah mereka. Kredit yang tidak digunakan kekal tersedia dan dibawa dari bulan ke bulan sehingga tamat tempoh 12 bulan selepas pembelian.

Kredit adalah tidak boleh dikembalikan. Beli hanya apa yang anda perlukan—anda sentiasa boleh menambah nilai kemudian. Jika ralat platform menyebabkan caj gagal, kami mungkin memulihkan kredit yang terjejas selepas siasatan. Tiada bayaran balik tunai.

Harga ditetapkan dalam kredit, bukan dolar. Setiap endpoint mempunyai kosnya sendiri—lihat lencana "Kredit / permintaan" di atas. Anda akan sentiasa tahu dengan tepat berapa yang anda belanjakan.

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Mata Wang

Bilangan permintaan

Calculator API — 135+ Online Calculators | YEB

Try it live

Calculate

Contoh

Contoh Respons

Kod Respons

Calculate

Parameters

Code Samples

Response

List Calculators

Contoh

Contoh Respons

Kod Respons

List Calculators

Parameters

Code Samples

Response

Calculator Info

Contoh

Contoh Respons

Kod Respons

Calculator Info

Parameters

Code Samples

Response

Search Calculators

Contoh

Contoh Respons

Kod Respons

Search Calculators

Parameters

Code Samples

Response

Calculator API — 135+ Online Calculators | YEB — Practical Guide

#What the Calculator API does

#Endpoints at a glance

#Available categories

#How the formula system works

#Multilingual support

#Common use cases

#Try it live

Soalan Lazim

What calculators are available?

How much does it cost?

What languages are supported?

Can I get the formula definition?

How does unit conversion work?

Adakah permintaan dengan ralat dikira dan memakan kredit?

Saya menemui pepijat atau mahu penyesuaian dalam API. Apa yang perlu dilakukan?

Apakah had kadar permintaan?

Bagaimana pembayaran dan penggunaan berfungsi?

Adakah kredit tamat tempoh?

Adakah kredit yang tidak digunakan dibawa ke hadapan?

Adakah anda menawarkan bayaran balik?

Berapakah kos setiap panggilan API?