Calculator Features

This page is mostly a duplicate of the "Welcome to NumPad" document that is shown by default when you visit NumPad. It will probably be more helpful to view that document as it's interactive and shows inline results. However it is possible to lose or edit that document; if this has happened to you, I recommend loading NumPad in a private browser window to see it again.

Arithmetic

NumPad has all the basics

  1 + 1
  2 - 1
  2 * 2
  5 / 2

You can also use "per" to divide and "to" to subtract, although "to" subtracts the left hand side from the right hand side

  20 miles per gallon
  30 to 50

And a "to the power of" operator

  3^2

And "mod" for modulo arithmetic

  15 mod 12

Units and Conversions

NumPad has a lot of built in units

  9.8 m/s^2
  3.6 roentgen

You can naturally combine units like feet and inches

  6 foot 2 inches

You can add and subtract units of the same dimension

  2kg + 1lb
  2 miles - 1km

The "in" operator converts between units

  £200 in USD
  100kg + 20lbs in tonnes

You can multiply and divide units even if they don't have the same dimensions

  20kg * 9.8m/s^2
  20 litres/minute

And raise them to powers or root them

  3feet^3 in l
  sqrt(20 acres) in m

NumPad even automatically handles conversions between units that are the inverse of one another

  26.2 miles / 3 hours 30 minutes in min/km
  4.6L/100km in miles / gallon

Variables

You can declare variables with the "=" sign and variable names can even contain spaces and apostrophes

  Alice's food = £30
  Bob's food = £25
  VAT  = 20%
  Alice's food + Bob's food + VAT

Line References

Line references are like variables, but they let you refer to the value of another line whether that line without declaring a variable. For clarity, I've started each line in the following examples with a line number, but you should not copy these into a NumPad document. NumPad can display line numbers in a column to the left of documents. If you don't see these you can go to settings and tick "show line numbers".

1 | 100
2 | line 1 * 2
3 | Line 1 * 3

Line references behave dynamically, so if you insert new lines before the line that's being referred to, your line reference will update to point to its line's new line number.

Line references are useful generally, but especially useful for ranges in functions.

Percentages

There is support for all the main percentage operations

  10% of $200
  $200 + 10%
  $200 - 10%
  
  $40 as a % of $50
  $60 as a % on $50
  $40 as a % off $50
  
  5% of what is $6
  5% on what is $210
  5% off what is $190

Dates and Times

NumPad has support for times...

  10:10
  17:30 - 2 hours 20 minutes

...dates...

  30th Sept
  1st January 1970 + 3 months

...and times with dates

  13:00 16th August 2022 - 2 weeks

Notice that times with unspecified dates default to the current day, dates with unspecified years default to the current year, and dates without unspecified times default to midday.

Functions

There are functions for finding the sum, mean, average and median of a list of numbers. Average is just an alias for the mean.

  sum(1, 2, 3)
  mean(1, 2, 3)
  average(1, 2, 3)
  median(1, 2, 20)

You can also give these functions a range. You can make a range by putting a colon between two line references, this is the same as passing the function all of the values of those line references. Ranges are inclusive, so line 1 : line 4 will include lines 1 and 4.

1 | 10
2 | 20
3 | 30
4 | 40
5 |
6 | sum(line 1 : line 4)

Ranges behave dynamically so that if you insert new lines between the lines of a range your range will be expanded to accomodate that line. Likewise they will contract if you remove lines in the range.

The sum, mean and median of all the values of the document are also shown in the bottom right hand corner of the window, though only when all values have the same dimension (e.g. all dollars, or all distances).

There are built in square root (sqrt) and cube root (cbrt) functions

  sqrt(9)
  cbrt(27)

Although if you want to find roots higher than 3 you'll have to raise your value to a fractional power, e.g.

  81^1/4

There is also support for basic trigonometry functions and their inverses

  sin(90 degrees)
  arccos(1) in degrees

There are natural logarithm "ln" and base 10 logarithm "log" functions too

  ln(e)
  log(1000)

Constants

NumPad has the following constants built in, you can add your own with variable assignment

  pi
  PI  
  e

Bases and base conversion

You can express numbers in binary, octal, and hexadecimal with the prefixes "0b", "0o", and "0x" respectively

  0b101010
  0o777
  0xcab1

You can convert them using the "in" operator

  4011 in hex
  0o52 in decimal
  51889 in hexadecimal
  0xcab1 in binary
  64 in octal