Used the calculator from 1010tires.com 205/40-16 is in red

Stock Tire - 205/50R15 Tire 1 - 205/40R16
Section Width: 8.07 in 205 mm
Section Width: 8.07 in 205 mm
Rim Diameter: 15 in 381 mm
Rim Diameter: 16 in 406.4 mm
Rim Width Range: 5.5 - 7.5 in
Rim Width Range: 7 - 8 in
Overall Diameter: 23.07 in 585.97 mm
Overall Diameter: 22.45 in 570.23 mm
Sidewall Height: 4.03 in 102.36 mm
Sidewall Height: 3.22 in 81.788 mm
Radius: 11.53 in 292.86 mm
Radius: 11.22 in 284.98 mm
Circumference: 72.47 in 1840.7 mm
Circumference: 70.52 in 1791.2 mm
Revs per Mile: 901.6
Revs per Mile: 926.5
Actual Speed: 60 mph 100 km/h
Speedometer1: 61.6 mph 102. km/h

Speedometer Difference: - Speedometer Difference: 2.761% too fast
Diameter Difference: - Diameter Difference: 2.69%