Math Tools' Numbers endpoints return structured JSON about a number — nominal, cardinal, and ordinal names, currency formatting, base conversion, and a rotating "number of the day" — under the same platform that also powers Math Tools' other calculator APIs. A public, keyless tier is rate-limited to a small number of calls per hour; higher volume requires registering for a free account and passing an API key.
AuthenticationAPI KeySign up with the provider to obtain credentials.
HTTPSSupportedTraffic is encrypted in transit.
CORSEnabledCallable directly from browser JavaScript.
PricingFreemiumA usable free tier exists, with paid plans for more volume.
FormatsJSONResponses can be requested as JSON.
GreatAPIs Score
Score81out of 100
Authentication15/25API key required
Pricing17/20Freemium tier available
Docs20/20Machine-readable spec file bundled
Formats9/15Single response format
Freshness20/20Verified within 6 months
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Auth quickstart
Sign up with the provider to get an API key.
Send it on every request as a headerX-Mathtools-Api-Secret: <key>
Stored keyNo key stored
Your key is stored only in this browser (localStorage) and sent directly to the API — never to greatapis.
Endpoints
Servers
https://api.math.toolshttp://api.math.tools
Auth
X-Mathtools-Api-Secret
Number of the day1
Number of the day. This API is free (rate limited).
GET/numbers/nod
Responses
Status
Description
Schema
200
200 Success response
—
401
401 Unauthorized response
—
Number Facts1
Get random interesting fact about a given number.
GET/numbers/fact
Parameters
Name
In
Required
Type
number
query
yes
integer
Responses
Status
Description
Schema
200
200 Success response
—
401
401 Unauthorized response
—
Number Generation1
Generate Random and interesting numbers.
GET/numbers/random
Parameters
Name
In
Required
Type
min
query
no
integer
max
query
no
integer
total
query
no
integer
Responses
Status
Description
Schema
200
200 Success response
—
401
401 Unauthorized response
—
Spell3
Spell out a number ordinal, cardinal or currency. This API is free (rate limited).
GET/numbers/cardinal
Parameters
Name
In
Required
Type
number
query
no
integer
language
query
no
string
Responses
Status
Description
Schema
200
200 Success response
—
401
401 Unauthorized response
—
GET/numbers/currency
Parameters
Name
In
Required
Type
number
query
no
integer
language
query
no
string
Responses
Status
Description
Schema
200
200 Success response
—
401
401 Unauthorized response
—
GET/numbers/ordinal
Parameters
Name
In
Required
Type
number
query
no
integer
Responses
Status
Description
Schema
200
200 Success response
—
401
401 Unauthorized response
—
Base Conversion4
Convert from one base to another. This API is free (rate limited).
GET/numbers/base
Parameters
Name
In
Required
Type
number
query
yes
integer
from
query
no
integer
to
query
yes
integer
Responses
Status
Description
Schema
200
200 success response
—
401
401 Unauthorized response
—
GET/numbers/base/binary
Parameters
Name
In
Required
Type
number
query
yes
integer
from
query
no
integer
Responses
Status
Description
Schema
200
200 success response
—
401
401 Unauthorized response
—
GET/numbers/base/hex
Parameters
Name
In
Required
Type
number
query
yes
integer
from
query
no
integer
Responses
Status
Description
Schema
200
200 success response
—
401
401 Unauthorized response
—
GET/numbers/base/octal
Parameters
Name
In
Required
Type
number
query
yes
integer
from
query
no
integer
Responses
Status
Description
Schema
200
200 success response
—
401
401 Unauthorized response
—
Number Systems Conversion3
Convert from one number system to another.
GET/numbers/numeral/chinese
Parameters
Name
In
Required
Type
number
query
no
integer
Responses
Status
Description
Schema
200
200 Success response
—
401
401 Unauthorized response
—
GET/numbers/numeral/egyptian
Parameters
Name
In
Required
Type
number
query
no
integer
Responses
Status
Description
Schema
200
200 Success response
—
401
401 Unauthorized response
—
GET/numbers/numeral/roman
Parameters
Name
In
Required
Type
number
query
no
integer
Responses
Status
Description
Schema
200
200 Success response
—
401
401 Unauthorized response
—
Prime8
Things to do with Prime numbers
GET/numbers/prime/factors
Parameters
Name
In
Required
Type
number
query
no
integer
Responses
Status
Description
Schema
200
200 Success response
—
401
401 Unauthorized response
—
GET/numbers/prime/is-fermat-prime
Parameters
Name
In
Required
Type
number
query
no
integer
Responses
Status
Description
Schema
200
200 Success response
—
401
401 Unauthorized response
—
GET/numbers/prime/is-fibonacci-prime
Parameters
Name
In
Required
Type
number
query
no
integer
Responses
Status
Description
Schema
200
200 Success response
—
401
401 Unauthorized response
—
GET/numbers/prime/is-mersenne-prime
Parameters
Name
In
Required
Type
number
query
no
integer
Responses
Status
Description
Schema
200
200 Success response
—
401
401 Unauthorized response
—
GET/numbers/prime/is-partition-prime
Parameters
Name
In
Required
Type
number
query
no
integer
Responses
Status
Description
Schema
200
200 Success response
—
401
401 Unauthorized response
—
GET/numbers/prime/is-pell-prime
Parameters
Name
In
Required
Type
number
query
no
integer
Responses
Status
Description
Schema
200
200 Success response
—
401
401 Unauthorized response
—
GET/numbers/prime/is-perfect
Parameters
Name
In
Required
Type
number
query
no
integer
Responses
Status
Description
Schema
200
200 Success response
—
401
401 Unauthorized response
—
GET/numbers/prime/is-prime
Parameters
Name
In
Required
Type
number
query
no
integer
Responses
Status
Description
Schema
200
200 Success response
—
401
401 Unauthorized response
—
PI1
Digits of PI and more.This API is free (rate limited).
GET/numbers/pi
Parameters
Name
In
Required
Type
from
query
no
integer
to
query
no
integer
Responses
Status
Description
Schema
200
200 Success response
—
401
401 Unauthorized response
—
Number Checks4
Check Property of a given number.
GET/numbers/is-cube
Parameters
Name
In
Required
Type
number
query
no
integer
Responses
Status
Description
Schema
200
200 Success response
—
401
401 Unauthorized response
—
GET/numbers/is-palindrome
Parameters
Name
In
Required
Type
number
query
no
integer
Responses
Status
Description
Schema
200
200 Success response
—
401
401 Unauthorized response
—
GET/numbers/is-square
Parameters
Name
In
Required
Type
number
query
no
integer
Responses
Status
Description
Schema
200
200 Success response
—
401
401 Unauthorized response
—
GET/numbers/is-triangle
Parameters
Name
In
Required
Type
number
query
no
integer
Responses
Status
Description
Schema
200
200 Success response
—
401
401 Unauthorized response
—
Try it
Developer reference
Base URLhttps://api.math.tools
Rate limit
Public, keyless calls are capped at 60 requests per day, distributed as 5 per hour. Passing an API key (free registration) raises the limit according to the account's service level/plan; paid-tier caps are shown in the account dashboard, not the public docs page.
