Binary Memory Map Calculator
Calculate the address range occupied by a memory region from its starting hexadecimal address and size in bytes. Find the inclusive end address, next free address and fixed-width binary start and end addresses.
Next Free Address = Start Address + Region Size
What Is a Binary Memory Map?
A memory map describes how one or more regions occupy locations in an address space. A region normally has a starting address, a defined size and an ending address. Memory maps are commonly used for RAM, ROM, flash memory, peripheral registers, firmware sections and memory-mapped hardware.
This calculator focuses on one memory region at a time. It determines the exact inclusive address range occupied by that region.
How the Binary Memory Map Calculator Works
Enter the first hexadecimal address of a memory region and its size in bytes. Because the first byte already occupies the starting address, the inclusive ending address is calculated using size minus one.
Size: 256 bytes
End: 0x2000 + 256 – 1
= 0x20FF
The region therefore occupies every byte address from 0x2000 through 0x20FF.
Memory Map End Address Formula
The most important formula is:
The subtraction of one is essential because start and end are both included in the address range.
Substituting the end-address formula gives the original region size.
Why End Address Uses Size Minus One
Consider a one-byte region beginning at address 0x1000. That single byte occupies address 0x1000 itself.
Size: 1 byte
End: 0x1000 + 1 – 1 = 0x1000
If the size were added without subtracting one, the calculated range would incorrectly contain two byte addresses.
256-Byte Memory Region Example
A common example is a 256-byte block beginning at hexadecimal address 0x4000.
Size: 256 = 0x100 bytes
End: 0x40FF
Next Free Address: 0x4100
The address range 0x4000 through 0x40FF contains exactly 256 byte locations.
1 KB Memory Region Example
One kibibyte contains 1024 bytes. If a 1024-byte region begins at 0x8000:
Start: 0x8000
End: 0x8000 + 0x400 – 1
= 0x83FF
The next available address immediately after this region is 0x8400.
Memory Map Start and End Addresses
The start address is the first byte included in the mapped region. The end address is the final byte included in the same region.
End: Included
Next Free Address: Not included
Keeping this distinction clear prevents off-by-one errors when defining firmware, flash or peripheral address ranges.
What Is the Next Free Address?
The first address after the mapped region is calculated as:
For example:
Size: 256
End: 0x20FF
Next Free: 0x2100
The next free address is useful when planning adjacent memory regions.
Binary Representation of Memory Addresses
Memory addresses are commonly displayed in hexadecimal, but each hexadecimal digit corresponds to four binary bits. This calculator therefore also displays the complete fixed-width binary start and end addresses.
0x20FF = 0010000011111111₂
Leading zero bits are preserved according to the selected address width.
Memory Map Address Width
Address width determines the largest address that can be represented.
| Address Width | Minimum | Maximum | Total Addresses |
|---|---|---|---|
| 8-bit | 0x00 | 0xFF | 256 |
| 16-bit | 0x0000 | 0xFFFF | 65,536 |
| 24-bit | 0x000000 | 0xFFFFFF | 16,777,216 |
| 32-bit | 0x00000000 | 0xFFFFFFFF | 4,294,967,296 |
16-Bit Memory Map Example
A 16-bit address space runs from decimal 0 through 65,535, or hexadecimal 0x0000 through 0xFFFF.
Suppose a 4 KB region starts at 0xA000:
Start: 0xA000
End: 0xA000 + 0x1000 – 1 = 0xAFFF
32-Bit Peripheral Memory Map Example
Microcontrollers commonly place peripherals at fixed addresses inside a larger 32-bit address space.
Region Size: 1024 bytes = 0x400
End: 0x400203FF
Next Free: 0x40020400
This describes the address range occupied by that peripheral block without decoding individual registers inside it.
Memory Map Overflow
The complete region must fit within the selected address width. For an 8-bit system, the highest valid address is 0xFF.
Size: 32 bytes
Required End: 0x10F
Because 0x10F requires more than eight address bits, the region cannot fit in the selected 8-bit address space. The calculator reports an overflow instead of wrapping the address.
Memory Maps in Embedded Systems
Embedded processors often divide their address space into flash memory, SRAM, peripheral buses, system-control blocks and other regions. Device reference manuals normally provide start addresses and region sizes for these areas.
Calculating the inclusive ending address can help verify whether a region fits inside an available address range or where the next region can begin.
Memory Maps for Flash and ROM
Firmware images are frequently placed at defined flash addresses. Knowing the start address and allocated size makes it possible to calculate the last address reserved for the image or partition.
Size: 65536 bytes = 0x10000
End: 0x0800FFFF
Actual flash-sector and erase-block restrictions should still be verified from the device documentation.
Memory Maps for RAM
RAM regions can also be represented by a start address and byte capacity. For example, a 32 KB SRAM region beginning at 0x20000000 occupies:
Start: 0x20000000
End: 0x20007FFF
Memory Map vs Memory Address Calculator
These two BinaryCon tools intentionally answer different questions.
| Tool | Inputs | Main Result |
|---|---|---|
| Binary Memory Address Calculator | Base address + byte offset | One target address |
| Binary Memory Map Calculator | Start address + region size | Inclusive address range |
Memory Map vs Storage Alignment
Storage alignment calculates padding needed to round a data size to a required boundary. Memory mapping instead calculates which addresses a region occupies.
Memory Map: Start + Size → End Address
The memory map calculator therefore does not automatically alter the supplied region size to meet alignment requirements.
Memory Map vs Cache Address Breakdown
A memory map concerns address ranges. Cache address breakdown concerns the bit fields of one specific memory address.
Cache Breakdown: Tag | Set Index | Block Offset
The calculations are related to computer memory but serve fundamentally different purposes.
Why This Calculator Uses One Region
Large system memory maps can contain dozens or hundreds of different regions with architecture-specific permissions, aliases, reserved sections and overlapping views. Automatically building an entire hardware memory map would require much more information than a generic calculator can reliably infer.
This tool therefore performs the exact reusable calculation: determine the address range of one known region from its start address and byte size.
Important Binary Memory Map Notes
The starting address is entered in hexadecimal.
The region size must be a positive whole number of bytes.
The ending address is inclusive.
End Address = Start Address + Size – 1.
Next Free Address = Start Address + Size.
The number of occupied addresses equals the region size in bytes for a byte-addressable system.
The complete memory region must fit inside the selected address width.
The calculator reports overflow rather than wrapping an address past the maximum supported value.
This tool does not calculate memory permissions, overlapping regions, virtual-memory translation, cache indexing, storage alignment or individual peripheral registers.
For real hardware, verify memory-region definitions using the processor, microcontroller or device reference manual.