So when you get scores in bridge such as +420 for making 4 spades non-vulnerable and the other team scores say +170 for making 4 spades but not bidding it…you can see there is a difference of 250 points…but how do those points reflect to the IMP’s?

Here is a handy IMP scoring table…

Difference in PointsIMPS
0-100
20-401
50-802
90-1203
130-1604
170-2105
220-2606
270-3107
320-3608
370-4209
430-49010
500-59011
600-74012
750-89013
900-109014
1100-129015
1300-149016
1500-174017
1750-199018
2000-224019
2250-249020
2500-299021
3000-349022
3500-399023
4000+24