String Memory Calculator
Estimate the memory strings occupy including object overhead and encoding.
About String Memory Calculator
Short strings are dominated by object overhead rather than content, so a forty-byte header on a ten-character string more than doubles its cost. Interning collapses duplicates to a single copy plus a reference. String duplication is extremely common in parsed data, which is why interning often reclaims a third or more of heap memory.
Formula
String Memory
Bytes per string = object overhead + length × bytes per character
- interning
- Storing one copy of each distinct value and referencing it
- bytes per character
- Two for UTF-16 runtimes, one for compact Latin storage
Worked example
With the default values below, String Memory Calculator returns Total Memory of 99.1821. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Number of stringsminimum 0
- 1,000,000
- Average length in charactersminimum 0
- 32
- Bytes per characteraccepts 1–4 bytes
- 2 bytes
- Per-string object overheadminimum 0 bytes
- 40 bytes
- Share that are duplicatesaccepts 0–100 %
- 40 %
Results
- Total Memory
- 99.1821 MB
- Memory After Interning Duplicates
- 67.1387 MB
- Bytes per String
- 104 bytes
- Memory Consumed by Object Overhead
- 38.1470 MB
- Saving From Interning
- 32.31%
Step by step
- 1Values used
- 2String Memory
- 3Total Memory= 99.1821 MB
- 4Memory After Interning Duplicates= 67.1387 MB
- 5Bytes per String= 104 bytes
- 6Memory Consumed by Object Overhead= 38.1470 MB
- 7Saving From Interning= 32.31
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 String Memory calculated?
Bytes per string = object overhead + length × bytes per character Short strings are dominated by object overhead rather than content, so a forty-byte header on a ten-character string more than doubles its cost. Interning collapses duplicates to a single copy plus a reference.
Why does String Memory matter?
String duplication is extremely common in parsed data, which is why interning often reclaims a third or more of heap memory.
What values do I need to enter?
This calculator takes 5 inputs: Number of strings, Average length in characters, Bytes per character, Per-string object overhead, Share that are duplicates. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.