6 converters. Strain as a ratio, a percent and in microstrain (µε), each with the formula and the math worked out with your numbers.
1,500 µε = 0.15%
0.2% = 2,000 µε
0.002 m/m = 2,000 µε
500 µε = 0.0005 m/m
0.05 m/m = 5%
2.5% = 0.03 m/m