I use Google Calculator for all of my swim questions like this.  For instance, go to Google.com and type in:

1500 meters in yards

Take the answer (1640), then type in:

1640 divided by 50

You will get the number of laps.   A lap is down and back, so I divide by 50. 

I swim in a 60 foot pool.  So, after a swim I do calculations like "120 feet times 30 in yards"  (30 being the number of laps I swam).

1500 meters = 1640.42 yards

÷25 yards = 65.62 lengths, or ~66 lengths

÷2 lengths/lab = 32.81 laps, or ~33 laps

Roughly speaking, a meter is about 10% longer than a yard, thus you would have to do 10% more of anything measured in yards to be equivalent to meters.