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

Hent API-nøkkel Kjøp kreditter

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.

Endepunkt:

99.9 % Oppetid

7ms Svar

20 req/s

0.001 Kreditter / forespørsel

Calculate


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

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

Eksempel

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": {}
}'

Svareksempel

{
  "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
}

Svarkoder

Kode	Beskrivelse
200 Success	Forespørsel behandlet OK.
400 Bad Request	Inngangsvalidering mislyktes.
401 Unauthorized	Manglende / feil API-nøkkel.
403 Forbidden	Nøkkel inaktiv eller ikke tillatt.
429 Rate Limit	For mange forespørsler.
500 Server Error	Uventet feil.

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	Type	Påkrevd	Beskrivelse
`api_key`	string	ja	Your API key
`category`	string	valgfri	Filter by category slug (e.g. "finance", "health", "math")
`locale`	string	valgfri	Language code for translated titles (default: en)
`limit`	integer	valgfri	Max results, 1–100 (default: 50)
`offset`	integer	valgfri	Skip N results for pagination (default: 0)

Eksempel

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
}'

Svareksempel

{
  "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
}

Svarkoder

Kode	Beskrivelse
200 Success	Forespørsel behandlet OK.
400 Bad Request	Inngangsvalidering mislyktes.
401 Unauthorized	Manglende / feil API-nøkkel.
403 Forbidden	Nøkkel inaktiv eller ikke tillatt.
429 Rate Limit	For mange forespørsler.
500 Server Error	Uventet feil.

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	Type	Påkrevd	Beskrivelse
`api_key`	string	ja	Your API key
`slug`	string	valgfri	Calculator slug (e.g. "bmi", "mortgage")
`calculator_id`	integer	valgfri	Calculator ID (alternative to slug)
`locale`	string	valgfri	Language code (default: en)

Eksempel

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

Svareksempel

{
  "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
}

Svarkoder

Kode	Beskrivelse
200 Success	Forespørsel behandlet OK.
400 Bad Request	Inngangsvalidering mislyktes.
401 Unauthorized	Manglende / feil API-nøkkel.
403 Forbidden	Nøkkel inaktiv eller ikke tillatt.
429 Rate Limit	For mange forespørsler.
500 Server Error	Uventet feil.

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	Type	Påkrevd	Beskrivelse
`api_key`	string	ja	Your API key
`query`	string	ja	Search query (minimum 2 characters)
`locale`	string	valgfri	Language code (default: en)
`limit`	integer	valgfri	Max results, 1–50 (default: 20)

Eksempel

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
}'

Svareksempel

{
  "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
}

Svarkoder

Kode	Beskrivelse
200 Success	Forespørsel behandlet OK.
400 Bad Request	Inngangsvalidering mislyktes.
401 Unauthorized	Manglende / feil API-nøkkel.
403 Forbidden	Nøkkel inaktiv eller ikke tillatt.
429 Rate Limit	For mange forespørsler.
500 Server Error	Uventet feil.

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 mar 2026, 00:16 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.

Ofte stilte spørsmål

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.

Ja. Hver forespørsel, selv de som resulterer i feil, forbruker kreditter. Kredittene dine er knyttet til antall forespørsler, uavhengig av suksess eller feil. Hvis feilen tydelig skyldes et plattformproblem på vår side, gjenoppretter vi de berørte kredittene (ingen kontantrefusjon).

Kontakt oss på [email protected]. Vi tar tilbakemeldinger på alvor—hvis feilrapporten eller funksjonsforespørselen din er meningsfull, kan vi fikse eller forbedre API-et raskt og gi deg 50 gratis kreditter som takk.

Det avhenger av API-et og noen ganger til og med av endepunktet. Noen endepunkter bruker data fra eksterne kilder, som kan ha strengere grenser. Vi håndhever også grenser for å forhindre misbruk og holde plattformen stabil. Sjekk dokumentasjonen for den spesifikke grensen for hvert endepunkt.

Vi opererer med et kredittsystem. Kreditter er forhåndsbetalte, ikke-refunderbare enheter du bruker på API-kall og verktøy. Kreditter forbrukes etter FIFO-prinsippet (eldste først) og er gyldige i 12 måneder fra kjøpsdatoen. Dashbordet viser hver kjøpsdato og dens utløp.

Ja. Alle kjøpte kreditter (inkludert brøkdeler) er gyldige i 12 måneder fra kjøpet. Ubrukte kreditter utløper automatisk og slettes permanent ved slutten av gyldighetsperioden. Utløpte kreditter kan ikke gjenopprettes eller konverteres til kontanter eller annen verdi. Overgangsregel: kreditter kjøpt før 22. sep. 2025 behandles som kjøpt 22. sep. 2025 og utløper 22. sep. 2026 (med mindre en tidligere utløpsdato ble oppgitt ved kjøpet).

Ja—innenfor gyldighetsperioden. Ubrukte kreditter forblir tilgjengelige og overføres fra måned til måned til de utløper 12 måneder etter kjøpet.

Kreditter er ikke-refunderbare. Kjøp bare det du trenger—du kan alltid fylle på senere. Hvis en plattformfeil forårsaker en mislykket belastning, kan vi gjenopprette de berørte kredittene etter undersøkelse. Ingen kontantrefusjon.

Prisene er satt i kreditter, ikke dollar. Hvert endepunkt har sin egen pris—se merket «Kreditter / forespørsel» ovenfor. Du vet alltid nøyaktig hva du bruker.

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Calculator API — 135+ Online Calculators | YEB

Try it live

Calculate

Eksempel

Svareksempel

Svarkoder

Calculate

Parameters

Code Samples

Response

List Calculators

Eksempel

Svareksempel

Svarkoder

List Calculators

Parameters

Code Samples

Response

Calculator Info

Eksempel

Svareksempel

Svarkoder

Calculator Info

Parameters

Code Samples

Response

Search Calculators

Eksempel

Svareksempel

Svarkoder

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

Ofte stilte spørsmål

What calculators are available?

How much does it cost?

What languages are supported?

Can I get the formula definition?

How does unit conversion work?

Teller forespørsler med feil og koster de kreditter?

Jeg fant en feil eller ønsker tilpasninger i API-ene. Hva gjør jeg?

Hva er hastighetsgrensen?

Hvordan fungerer betaling og bruk?

Utløper kreditter?

Overføres ubrukte kreditter?

Tilbyr dere refusjoner?

Hva koster hvert API-kall?