RAM Calculator
Calculate total RAM capacity from installed sticks, or theoretical memory bandwidth from RAM speed and bus width.
Total RAM Capacity
32 GB
How to Calculate RAM Capacity and Bandwidth
This calculator covers two common RAM questions: how much total memory you have across multiple sticks, and how much theoretical memory bandwidth a given RAM speed and bus width can deliver. Use the capacity mode to add up installed memory, or the bandwidth mode to estimate peak data transfer rate.
Example
Two 16 GB sticks give a total capacity of 2 × 16 = 32 GB. Separately, DDR4-3200 RAM with the standard 64-bit bus width has a theoretical bandwidth of (3200 × 64) ÷ 8 ÷ 1000 ≈ 25.6 GB/s per stick — dual-channel setups effectively double this to around 51.2 GB/s.
Common Use Cases
- Checking your total installed RAM capacity when planning an upgrade.
- Estimating theoretical memory bandwidth for a given RAM speed rating.
- Comparing bandwidth across different RAM speed grades (e.g. DDR4-3200 vs DDR5-6000).
FAQs
Why is the bus width usually 64 bits?
A standard single memory channel on desktop and laptop platforms has a 64-bit (8-byte) wide data path, which is why 64 is the default here. Some specialized systems use wider or narrower buses, which you can enter manually.
Is this the real-world bandwidth I'll see?
This is the theoretical peak bandwidth for a single channel at the rated speed. Actual achieved bandwidth is typically lower due to memory controller overhead, timings/latency, and whether you're running in single-, dual-, or quad-channel mode — multiply by the number of channels for a rough multi-channel estimate.
Does more RAM capacity mean faster performance?
Not directly — capacity determines how much data can be held in memory at once, while bandwidth (driven by speed and channel count) determines how fast that data can be read and written. Both matter, but for different reasons: capacity avoids swapping to disk, while bandwidth affects throughput-sensitive tasks.