MikroTik Bandwidth Calculator (Simple Queue, Burst, PCQ, FQ-CoDel)

Bandwidth management in MikroTik RouterOS ensures fair link sharing across all clients while preventing bufferbloat—the latency spike that occurs when a single device saturates the upstream ISP modem queue. This calculator computes queue parameters across the three primary traffic-shaping strategies in RouterOS v7: per-client Simple Queues with Burst, Per Connection Queue (PCQ) for dynamic multi-user networks, and FQ-CoDel (Fair Queuing Controlled Delay) for modern low-latency packet scheduling. Under MikroTik's Hierarchical Token Bucket (HTB) scheduler, every child queue relies on two foundational rates: Limit-At (Committed Information Rate / CIR), which guarantees a minimum bandwidth floor during peak congestion, and Max-Limit (Maximum Information Rate / MIR), which caps a client's throughput when spare capacity is available on the parent queue. To take control of the bottleneck away from the ISP modem or ONT, the parent queue Max-Limit should always be shaped to 90%–95% (headroom) of the measured ISP line rate. MikroTik's token-bucket Burst mechanism temporarily allows a client to exceed Max-Limit up to Burst-Limit as long as the sliding-window average rate over Burst-Time remains below Burst-Threshold. The most common field misconfigurations are setting Burst-Threshold equal to or higher than Max-Limit—which prevents burst from ever triggering—and leaving IPv4 FastTrack enabled in the firewall filter table, which causes packets to bypass Simple Queues and global Queue Trees entirely.