Little bits of Bytes (and Bits)

Posted March 26, 2025

Updated June 03, 2025

2 minutes

Decimal Units

Name	Unit	Total Bytes
Exabytes	EB	1,000,000,000,000,000,000
Petabytes	PB	1,000,000,000,000,000
Terabytes	TB	1,000,000,000,000
Gigabytes	GB	1,000,000,000
Megabytes	MB	1,000,000
Kilobytes	KB	1,000

Binary Units

Name	Unit	Magnitude	Total Bytes
Exbibyte	EiB	2^60	1,152,921,504,606,846,976
Pebibyte	PiB	2^50	1,125,899,906,842,624
Tebibyte	TiB	2^40	1,099,511,627,776
Gibibyte	GiB	2^30	1,073,741,824
Mebibyte	MiB	2^20	1,048,576
Kibibyte	KiB	2^10	1,024

Generating Byte String

C++

inline static std::string createBytesString(size_t bytes)
{
    size_t constexpr b10 = size_t(1) << 10;
    size_t constexpr b20 = size_t(1) << 20;
    size_t constexpr b30 = size_t(1) << 30;
    size_t constexpr b40 = size_t(1) << 40;
    size_t constexpr b50 = size_t(1) << 50;
    size_t constexpr b60 = size_t(1) << 60;

    if (bytes < b10) return std::to_string(bytes) + " bytes";
    else if (bytes < b20) return std::to_string(bytes / b10) + " KiB";
    else if (bytes < b30) return std::to_string(bytes / b20) + " MiB";
    else if (bytes < b40) return std::to_string(bytes / b30) + " GiB";
    else if (bytes < b50) return std::to_string(bytes / b40) + " TiB";
    else if (bytes < b60) return std::to_string(bytes / b50) + " PiB";
    return std::to_string(bytes / b60) + " EiB";
}

Python

def create_bytes_string(bytes):
    b10 = 1 << 10  
    b20 = 1 << 20  
    b30 = 1 << 30  
    b40 = 1 << 40  
    b50 = 1 << 50  
    b60 = 1 << 60  
    
    if bytes < b10:
        return f"{bytes} bytes"
    elif bytes < b20:
        return f"{bytes // b10} KiB"
    elif bytes < b30:
        return f"{bytes // b20} MiB"
    elif bytes < b40:
        return f"{bytes // b30} GiB"
    elif bytes < b50:
        return f"{bytes // b40} TiB"
    elif bytes < b60:
        return f"{bytes // b50} PiB"
    return f"{bytes // b60} EiB"