What is the smallest monetary unit in Tezos, and where is it defined in the code?

1 Answer 1


Currently 1 tez (1 XTZ) is divisible to six decimal places, and the smallest unit is called a micro tez (mutez).

1 tez = 1,000,000 micro tez

In code it is referred to as one_mutez and it is defined in src/proto_013_PtJakart/lib_protocol/tez_repr.ml:

(* all other constant are defined from the value of one micro tez *)
let one_mutez = Tez_tag 1L

let max_mutez = Tez_tag Int64.max_int

let mul_int (Tez_tag tez) i = Tez_tag (Int64.mul tez i)

let one_cent = mul_int one_mutez 10_000L

let fifty_cents = mul_int one_cent 50L

(* 1 tez = 100 cents = 1_000_000 mutez *)
let one = mul_int one_cent 100L
  • 4
    The Tezos shell also makes use of "nanotez" in fine-grained calculations for fees, where 1000 nanotez = 1 mutez. I believe such values are rounded (truncated?) to mutez before being passed to the protocol proper and stored in the persistent chain data. Commented Oct 16, 2019 at 17:55

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