What it is
CONUS COLA is a small taxable allowance paid in a limited number of expensive stateside locations. Most members never see it. It depends on duty station, grade, years of service, and dependents.
2026 rate
Varies by location. Most duty stations pay zero.
What goes wrong
If you PCS out of a COLA area and it keeps paying, that becomes a debt. If you PCS into one and it never starts, you are losing money each month.