> For the complete documentation index, see [llms.txt](https://mariadb.com/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://mariadb.com/docs/server/reference/data-types/data-type-storage-requirements.md). # Data Type Storage Requirements The following tables indicate the approximate data storage requirements for each data type. ## Numeric Data Types | Data Type | Storage Requirement | | ------------------------------------------------------------------------------ | ------------------------------------- | | [TINYINT](/docs/server/reference/data-types/numeric-data-types/tinyint.md) | 1 byte | | [SMALLINT](/docs/server/reference/data-types/numeric-data-types/smallint.md) | 2 bytes | | [MEDIUMINT](/docs/server/reference/data-types/numeric-data-types/mediumint.md) | 3 bytes | | [INT](/docs/server/reference/data-types/numeric-data-types/int.md) | 4 bytes | | [BIGINT](/docs/server/reference/data-types/numeric-data-types/bigint.md) | 8 bytes | | [FLOAT](/docs/server/reference/data-types/numeric-data-types/float.md)(p) | 4 bytes if p <= 24, otherwise 8 bytes | | [DOUBLE](/docs/server/reference/data-types/numeric-data-types/double.md) | 8 bytes | | [DECIMAL](/docs/server/reference/data-types/numeric-data-types/decimal.md) | See table below | | [BIT](/docs/server/reference/data-types/numeric-data-types/bit.md)(M) | (M+7)/8 bytes | Note that `MEDIUMINT` columns will require 4 bytes in memory (for example, in InnoDB buffer pool). ### Decimal [Decimals](/docs/server/reference/data-types/numeric-data-types/decimal.md) are stored using a binary format, with the integer and the fraction stored separately. Each nine-digit multiple requires 4 bytes, followed by a number of bytes for whatever remains, as follows: | Remaining digits | Storage Requirement | | ---------------- | ------------------- | | 0 | 0 bytes | | 1 | 1 byte | | 2 | 1 byte | | 3 | 2 bytes | | 4 | 2 bytes | | 5 | 3 bytes | | 6 | 3 bytes | | 7 | 4 bytes | | 8 | 4 bytes | ## String Data Types In the descriptions below, `M` is the declared column length (in characters or in bytes), while `len` is the actual length in bytes of the value. | Data Type | Storage Requirement | | ---------------------------------------------------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------- | | [ENUM](/docs/server/reference/data-types/string-data-types/enum.md) | 1 byte for up to 255 enum values, 2 bytes for 256 to 65,535 enum values | | [CHAR(M)](/docs/server/reference/data-types/string-data-types/char.md) | M × w bytes, where w is the number of bytes required for the maximum-length character in the character set | | [BINARY(M)](/docs/server/reference/data-types/string-data-types/binary.md) | M bytes | | [VARCHAR(M)](/docs/server/reference/data-types/string-data-types/varchar.md), [VARBINARY(M)](/docs/server/reference/data-types/string-data-types/varbinary.md) | len + 1 bytes if column is 0 – 255 bytes, len + 2 bytes if column may require more than 255 bytes | | [TINYBLOB](/docs/server/reference/data-types/string-data-types/tinyblob.md), [TINYTEXT](/docs/server/reference/data-types/string-data-types/tinytext.md) | len + 1 bytes | | [BLOB](/docs/server/reference/data-types/string-data-types/blob.md), [TEXT](/docs/server/reference/data-types/string-data-types/text.md) | len + 2 bytes | | [MEDIUMBLOB](/docs/server/reference/data-types/string-data-types/mediumblob.md), [MEDIUMTEXT](/docs/server/reference/data-types/string-data-types/mediumtext.md) | len + 3 bytes | | [LONGBLOB](/docs/server/reference/data-types/string-data-types/longblob.md), [LONGTEXT](/docs/server/reference/data-types/string-data-types/longtext.md) | len + 4 bytes | | [XMLTYPE](/docs/server/reference/data-types/string-data-types/xmltype.md) | len + 4 bytes (same as LONGBLOB) | | [SET](/docs/server/reference/data-types/string-data-types/set-data-type.md) | Given M members of the set, (M+7)/8 bytes, rounded up to 1, 2, 3, 4, or 8 bytes | | [INET6](/docs/server/reference/data-types/string-data-types/inet6.md) | 16 bytes | | [UUID](/docs/server/reference/data-types/string-data-types/uuid-data-type.md) | 16 bytes | **Note**: Introduced in MariaDB 12.3, the `XMLTYPE` data type has a maximum storage capacity of 4GB, similar to `LONGBLOB`*.* In some [character sets](/docs/server/reference/data-types/string-data-types/character-sets.md), not all characters use the same number of bytes. utf8 encodes characters with one to three bytes per character, while `utf8mb4` requires one to four bytes per character. When using field the `COMPRESSED` attribute, 1 byte is reserved for metadata. For example, `VARCHAR(255)` will use +2 bytes instead of +1. ### Examples Assuming a single-byte character-set: | Value | CHAR(2) | Storage Required | VARCHAR(2) | Storage Required | | ----- | ------- | ---------------- | ---------- | ---------------- | | '' | ' ' | 2 bytes | '' | 1 byte | | '1' | '1 ' | 2 bytes | '1' | 2 bytes | | '12' | '12' | 2 bytes | '12' | 3 bytes | ## Date and Time Data Types | Data Type | Storage Requirement | | ------------------------------------------------------------------------------------ | ------------------- | | [DATE](/docs/server/reference/data-types/date-and-time-data-types/date.md) | 3 bytes | | [TIME](/docs/server/reference/data-types/date-and-time-data-types/time.md) | 3 bytes | | [DATETIME](/docs/server/reference/data-types/date-and-time-data-types/datetime.md) | 8 bytes | | [TIMESTAMP](/docs/server/reference/data-types/date-and-time-data-types/timestamp.md) | 4 bytes | | [YEAR](/docs/server/reference/data-types/date-and-time-data-types/year-data-type.md) | 1 byte | ### Microseconds MariaDB defaults to the MySQL format (by means of the [mysql56\_temporal\_format](/docs/server/server-management/variables-and-modes/server-system-variables.md#mysql56_temporal_format) variable). Microseconds have the following additional storage requirements: | Precision | Storage Requirement | | --------- | ------------------- | | 0 | 0 bytes | | 1,2 | 1 byte | | 3,4 | 2 bytes | | 5,6 | 3 bytes | ## NULL Values For the InnoDB [COMPACT](/docs/server/server-usage/storage-engines/innodb/innodb-row-formats/innodb-compact-row-format.md), [DYNAMIC](/docs/server/server-usage/storage-engines/innodb/innodb-row-formats/innodb-dynamic-row-format.md) and [COMPRESSED](/docs/server/server-usage/storage-engines/innodb/innodb-row-formats/innodb-compressed-row-format.md) row formats, a number of bytes will be allocated in the record header for the nullable fields. If there are between 1 and 8 nullable fields, 1 such byte will be allocated. In the record payload area, no space will be reserved for values that are `NULL`. For the [InnoDB REDUNDANT row format](/docs/server/server-usage/storage-engines/innodb/innodb-row-formats/innodb-redundant-row-format.md), the overhead is 1 bit in the record header (as a part of the 1-byte or 2-byte "end of field" pointer). In that format, a `NULL` fixed-length field will consume the same amount of space as any `NOT NULL` value in the record payload area. The motivation is that it is possible to update in place between `NOT NULL` and `NULL` values. In other formats, `NULL` values usually require 1 bit in the data file, 1 byte in the index file. *This page is licensed: CC BY-SA / Gnu FDL* {% @marketo/form formId="4316" %}