Excel formulas to calculate IP values - Works in Excel and Google Sheet.

Updated March 16. 2023

Prerequisites:

A1 contains an IP address, such as 10.0.0.2
B1 contains the number of bits in the netmask (CIDR) such as 24

The below formulas then go into C1, D1 etc. to perform the various calculations. Some calculations depends on other calculations.

A Google Sheet with all the formulas can be accessed and copied here: https://docs.google.com/spreadsheets/d/1G-vStX0DRB7tq-wvbALnL4HeXYXXOkjh_GriTN-b6-o (Also updated march 16. 2023)

Note, the formulas below are written with the comma spreadsheet notation used in many countries globally. You may need to change the notation to semicolon notation, which is primearly used in the U.S. E.g. =ROUND(PI(),3) and =ROUND(PI();3) are identical but uses different formula notation.

Huge thanks to @6d6163 and @Baribf for pointing out a mistake when used in Excel (The instance_num in Substitute() must not be zero!) and for spotting that the StartIP in a range must be one higher than the range number. They also spotted a copy/paste error mixing up A1 and C1. Their work is what triggred the march 16. 2023 update of these formulas.

C1: Calculate netmask

=BIN2DEC(MID(REPT("1",B1)&REPT("0",32-B1),1,8))
&"."&
BIN2DEC(MID(REPT("1",B1)&REPT("0",32-B1),9,8))
&"."&
BIN2DEC(MID(REPT("1",B1)&REPT("0",32-B1),17,8))
&"."&
BIN2DEC(MID(REPT("1",B1)&REPT("0",32-B1),25,8))

D1: Calculate start of IP range

=BITAND( 
  (LEFT(A1, FIND(CHAR(160),SUBSTITUTE(A1,".",CHAR(160),1))-1)),
  (BIN2DEC(MID(REPT("1",B1)&REPT("0",32-B1),1,8)))
)
&"."&
BITAND(
  (MID(A1, FIND(CHAR(160),SUBSTITUTE(A1,".",CHAR(160),1))+1,FIND(CHAR(160),SUBSTITUTE(A1,".",CHAR(160),2))-FIND(CHAR(160),SUBSTITUTE(A1,".",CHAR(160),1))-1)),
  (BIN2DEC(MID(REPT("1",B1)&REPT("0",32-B1),9,8)))
)
&"."&
BITAND(
  (MID(A1, FIND(CHAR(160),SUBSTITUTE(A1,".",CHAR(160),2))+1,FIND(CHAR(160),SUBSTITUTE(A1,".",CHAR(160),3))-FIND(CHAR(160),SUBSTITUTE(A1,".",CHAR(160),2))-1)),
  (BIN2DEC(MID(REPT("1",B1)&REPT("0",32-B1),17,8)))
)
&"."&
BITAND(
  (MID(A1, FIND(CHAR(160),SUBSTITUTE(A1,".",CHAR(160),3))+1,FIND(CHAR(160),SUBSTITUTE(A1&".",".",CHAR(160),4))-FIND(CHAR(160),SUBSTITUTE(A1,".",CHAR(160),3))-1)), 
  (BIN2DEC(MID(REPT("1",B1)&REPT("0",32-B1),25,8)))
)+1

E1: Calculate end of IP range

=BITOR(
  (LEFT(A1, FIND(CHAR(160),SUBSTITUTE(A1,".",CHAR(160),1))-1)),
  (255-BIN2DEC(MID(REPT("1",B1)&REPT("0",32-B1),1,8)))
)
&"."&
BITOR(
  (MID(A1, FIND(CHAR(160),SUBSTITUTE(A1,".",CHAR(160),1))+1,FIND(CHAR(160),SUBSTITUTE(A1,".",CHAR(160),2))-FIND(CHAR(160),SUBSTITUTE(A1,".",CHAR(160),1))-1)),
  (255-BIN2DEC(MID(REPT("1",B1)&REPT("0",32-B1),9,8)) )
)
&"."&
BITOR(
  (MID(A1, FIND(CHAR(160),SUBSTITUTE(A1,".",CHAR(160),2))+1,FIND(CHAR(160),SUBSTITUTE(A1,".",CHAR(160),3))-FIND(CHAR(160),SUBSTITUTE(A1,".",CHAR(160),2))-1)),
  (255-BIN2DEC(MID(REPT("1",B1)&REPT("0",32-B1),17,8)))
)
&"."&
BITOR(
  (MID(A1, FIND(CHAR(160),SUBSTITUTE(A1,".",CHAR(160),3))+1,FIND(CHAR(160),SUBSTITUTE(A1&".",".",CHAR(160),4))-FIND(CHAR(160),SUBSTITUTE(A1,".",CHAR(160),3))-1)),
  (255-BIN2DEC(MID(REPT("1",B1)&REPT("0",32-B1),25,8)))
)-1

F1: Calculate Broadcast IP

=BITOR(
  (LEFT(A1, FIND(CHAR(160),SUBSTITUTE(A1,".",CHAR(160),1))-1)),
  (255-BIN2DEC(MID(REPT("1",B1)&REPT("0",32-B1),1,8)))
)
&"."&
BITOR(
  (MID(A1, FIND(CHAR(160),SUBSTITUTE(A1,".",CHAR(160),1))+1,FIND(CHAR(160),SUBSTITUTE(A1,".",CHAR(160),2))-FIND(CHAR(160),SUBSTITUTE(A1,".",CHAR(160),1))-1)),
  (255-BIN2DEC(MID(REPT("1",B1)&REPT("0",32-B1),9,8)))
)
&"."&
BITOR(
  (MID(A1, FIND(CHAR(160),SUBSTITUTE(A1,".",CHAR(160),2))+1,FIND(CHAR(160),SUBSTITUTE(A1,".",CHAR(160),3))-FIND(CHAR(160),SUBSTITUTE(A1,".",CHAR(160),2))-1)),
  (255-BIN2DEC(MID(REPT("1",B1)&REPT("0",32-B1),17,8)))
)
&"."&
BITOR(
  (MID(A1, FIND(CHAR(160),SUBSTITUTE(A1,".",CHAR(160),3))+1,FIND(CHAR(160),SUBSTITUTE(A1&".",".",CHAR(160),4))-FIND(CHAR(160),SUBSTITUTE(A1,".",CHAR(160),3))-1)),
  (255-BIN2DEC(MID(REPT("1",B1)&REPT("0",32-B1),25,8)))
)

G1: Calculate number of hosts

=2^(32-B1)-2

Example

For an IP setup such as 10.100.10.20/20 the following values will be calculated:

Netmask: 255.255.240.0
Start IP: 10.100.0.1
End IP: 10.100.15.254
Broadcast IP: 10.100.15.255
Number of hosts: 4094

RobinsonShai/excel formulas.md