Race pace calculator

I want to run a: 1 km 1500 m 1 mijl 2 km 3 km 2 mijlen 5 km 8 km 5 mijlen 10 km 12 km 15 km 10 mijlen 20 km Halve marathon 25 km 30 km 20 mijlen 40 km Marathon 50 km 100 km  in a time of hrs mins seconds

And I want to run Very negative (48/52) Negative (49/51) Even (50/50) Positive (51/49) Very positive (52/48) splits in two even paced halves gradually changing pace