All, What happens when you add one to a large floating-point number. 10 X=8.58993459E9 20 X=X-100 30 PRINT X 40 X=X+1 50 FOR T=1 TO 600:NEXT T 60 GOTO 30 There's likely some rounding going on. And it stops counting at the value shown in line 10. John Mark Mobley