Calculator
Evaluate mathematical expressions: arithmetic, algebra, trig, logarithms, unit conversions, and plain English queries.
⚡ 1 credit per call
Try it
Fill in the fields below and hit Send.
Why use this
Models get maths wrong. This offloads calculation to a proper evaluator. Accepts mathjs syntax or plain English.
Pricing
| Any call | 1 credit |
|---|
Request format
Send a single expression field — either mathjs syntax or plain English:
{ "expression": "sqrt(144)" }
{ "expression": "square root of 144" }
Plain English input is echoed back in its normalised mathjs form:
{ "result": 12, "expression": "sqrt(144)" }
What you can send
mathjs expressions
Anything the mathjs expression parser accepts:
2 + 3 * 4 → 14
(2 + 3) * 4 → 20
sqrt(81) → 9
2^8 → 256
pi * 5^2 → 78.54...
log(100, 10) → 2
sin(pi / 2) → 1
Unit conversions (mathjs native)
1 mile to km → 1.609...
1 feet to m → 0.3048
100 celsius to fahrenheit → 212
32 fahrenheit to celsius → 0
Plain English
what is 2 + 2 → 4
15 percent of 340 → 51
15% of 340 → 51
square root of 144 → 12
cube root of 27 → 3
2 to the power of 8 → 256
9 squared → 81
3 cubed → 27
half of 60 → 30
double 15 → 30
10 plus 5 → 15
10 divided by 5 → 2
Error responses
Invalid or unrecognisable expressions return 400 — no credit charged:
{
"error": "VALIDATION_ERROR",
"message": "Cannot evaluate: \"banana phone\". Try a mathjs expression (e.g. \"sqrt(144)\") or plain English (e.g. \"square root of 144\")."
}
API Reference
Endpoint
POST https://api.lightningapi.tools/calculator/calculate
Required headers
Authorization: Bearer <apiKey>
Content-Type: application/json
Example request
{
"expression": "sqrt(144)"
}
Example response
{
"result": 12,
"expression": "sqrt(144)"
}