Two Level Cache Average Access Time Calculator
Calculate average memory access time and path probabilities for serial L1, L2 and memory lookups.
YOUR CALCULATION
Result
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Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Weight each serial path by its probability. L2 hit rate is conditional on an L1 miss; all requests pay L1 lookup time.
AMAT=t1+(1−h1)[t2+(1−h2)tm]
Worked example
L1 hit 90%, conditional L2 hit 80%, times 1 ns + 5 ns + 100 ns give AMAT=1+0.1(5+0.2×100)=3.5 ns.
Assumptions and input details
Times are incremental costs, not already accumulated path latencies. Hit rates are entered long-run proportions. The model is blocking and serial; no overlapping lookup, prefetch, write buffer, cache-line transfer, bandwidth saturation or contention is included. Path contributions sum to the average. Rates of 0% and 100% are supported.
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
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