Effort is a real dial on Opus 5.5 and nearly flat on Opus 5
Cost per task at list prices, 13 single-shot tasks, 3 repeats each, 39 calls per cell. Accuracy was 97% or better in every cell.
Claude Opus 5.5
Claude Opus 5
$0.000
$0.005
$0.010
$0.016
$0.021
$0.026
$0.0072
$0.0204
default
$0.0060
$0.0201
low
$0.0085
$0.0200
medium
$0.0094
$0.0206
high
$0.0111
$0.0197
xhigh
$0.0240
$0.0220
max
At its default setting Opus 5.5 costs $0.0072 per task against Opus 5's $0.0204, at the same accuracy.
Only at max effort does Opus 5.5 cost more than Opus 5. Measured 2026-09-23.