Array Memory Calculator
Calculate the memory an array occupies including per-element and header overhead.
About Array Memory Calculator
Dynamic arrays reserve spare capacity so appends stay amortised constant time, which means allocated memory exceeds the data held. Arrays of references cost an extra pointer per element on top of the objects themselves. Choosing a typed or primitive array over a reference array can halve memory use for large numeric datasets.
Formula
Array Memory
Memory = elements × (element size + reference size) × (1 + spare capacity) + header
- spare capacity
- Dynamic arrays over-allocate so appends are amortised constant time
- indirection
- Reference arrays store a pointer per element plus the object itself
Worked example
With the default values below, Array Memory Calculator returns Total Memory of 9.5368. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Number of elementsminimum 0
- 1,000,000
- Bytes per elementminimum 0 bytes
- 8 bytes
- Array header overheadminimum 0 bytes
- 24 bytes
- Spare capacity reserved for growthaccepts 0–100 %
- 25 %
- Elements are referencesone of No, stored inline, Yes, stored as references
- No, stored inline
Results
- Total Memory
- 9.5368 MB
- Total Memory
- 10,000,024 bytes
- Memory Holding Data
- 8,000,000 bytes
- Memory Consumed by Overhead
- 2,000,024 bytes
- Share That Is Overhead
- 20.000%
Step by step
- 1Values used
- 2Array Memory
- 3Total Memory= 9.5368 MB
- 4Total Memory= 10,000,024 bytes
- 5Memory Holding Data= 8,000,000 bytes
- 6Memory Consumed by Overhead= 2,000,024 bytes
- 7Share That Is Overhead= 20.000
Assumptions and limits
- The result is derived only from the 5 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
How is Array Memory calculated?
Memory = elements × (element size + reference size) × (1 + spare capacity) + header Dynamic arrays reserve spare capacity so appends stay amortised constant time, which means allocated memory exceeds the data held. Arrays of references cost an extra pointer per element on top of the objects themselves.
Why does Array Memory matter?
Choosing a typed or primitive array over a reference array can halve memory use for large numeric datasets.
What values do I need to enter?
This calculator takes 5 inputs: Number of elements, Bytes per element, Array header overhead, Spare capacity reserved for growth, Elements are references. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.