What this calculator does
CAS latency (CL) is measured in memory clock cycles, not seconds, so comparing CL numbers alone across different memory speeds is misleading. This calculator converts CL and data rate into true latency in nanoseconds, the actual real-world delay.
The formula
Since DDR memory transfers data on both clock edges, the actual memory clock in MHz is half the quoted data rate in MT/s. True latency in nanoseconds is then ns = (CL / (MT/s ÷ 2)) × 1000. For example, DDR4-3200 CL16 works out to (16 / 1600) × 1000 = 10 ns.
This is why a higher-CL kit at a faster data rate can still have equal or lower real latency than a lower-CL kit at a slower data rate — the true nanosecond figure is what actually matters for responsiveness.
Last reviewed August 2026