# Convert Slots to POSIX Time

By

Travis Horn

The time in Plutus is described in POSIX time (the number of milliseconds that have elapsed since 1 January 1970 00:00:00.000). But the time in Plutus Playground is described in "slots". Each slot is 1000 milliseconds starting at 29 July 2020 9:44:51.000.

Slot 0 (the first slot) ends at 29 July 2020 9:44:51.999 (1596059091999).

Slot 1 ends at 29 July 2020 9:44:52.999 (1596059092999).

And so on.

If you need to calculate the POSIX time at the end of a specific slot, there is a function in Plutus that will convert slots to POSIX time called slotToEndPOSIXTime. It takes two parameters:

• SlotConfig: A datatype to configure the length (ms) of one slot and the beginning of the first slot
• Slot: The number of slots to show the time for

SlotConfig for Plutus Playground is a defined standard.

You can find out what (for example) 10 slots past the start time of Plutus Playground's standard config is with this function.

Change into the plutus-apps directory

cd plutus-apps

Start a Nix shell

nix-shell

Change into the Plutus Pioneer Program's week 1 directory

cd plutus-pioneer-program/code/week01

Start the REPL

cabal repl

In the REPL, import the following modules

import Data.Default
import Ledger.TimeSlot

Now you can use the function to determine the POSIX time for the end of 10 slots.

slotToEndPOSIXTime def 10

The corresponding POSIX time is shown:

POSIXTime {getPOSIXTime = 1596059101999}

Some arbitrary conversions are: