What's the formula for the rds mysql gp2 throughput as a function of volume size?

Formula is on this page:
https://docs.aws.amazon.com/ebs/latest/userguide/general-purpose.html

gp2 volume performance

IOPS performance
Baseline IOPS performance scales linearly between a minimum of 100 and a maximum of 16,000 at a rate of 3 IOPS per GiB of volume size. IOPS performance is provisioned as follows:

• Volumes 33.33 GiB and smaller are provisioned with the minimum of 100 IOPS.
• Volumes larger than 33.33 GiB are provisioned with 3 IOPS per GiB of volume size up to the maximum of 16,000 IOPS, which is reached at 5,334 GiB (3 X 5,334).
• Volumes 5,334 GiB and larger are provisioned with 16,000 IOPS.

gp2 volumes smaller than 1 TiB (and that are provisioned with less than 3,000 IOPS) can burst to 3,000 IOPS when needed for an extended period of time. A volume's ability to burst is governed by I/O credits. When I/O demand is greater than baseline performance, the volume spends I/O credits to burst to the required performance level (up to 3,000 IOPS). While bursting, I/O credits are not accumulated and they are spent at the rate of IOPS that is being used above baseline IOPS (spend rate = burst IOPS - baseline IOPS). The more I/O credits a volume has accrued, the longer it can sustain its burst performance. You can calculate Burst duration as follows:

                        (I/O credit balance)
Burst duration  =  ------------------------------
                   (Burst IOPS) - (Baseline IOPS)

Throughput performance
gp2 volumes deliver throughput between 128 MiB/s and 250 MiB/s, depending on the volume size. Throughput performance is provisioned as follows:

• Volumes that are 170 GiB and smaller deliver a maximum throughput of 128 MiB/s.
• Volumes larger than 170 GiB but smaller than 334 GiB can burst to a maximum throughput of 250 MiB/s.
• Volumes that are 334 GiB and larger deliver 250 MiB/s.

Throughput for a gp2 volume can be calculated using the following formula, up to the throughput limit of 250 MiB/s:

Throughput in MiB/s = IOPS performance × I/O size in KiB / 1,024