@tooba_usman said in How do you convert swimming times from meters to yards?:
use google 
But I would rather say 
The formulas below are used in San Diego – Imperial Swimming to convert short course yards times to meter times, and vice versa.
(Some definitions: * means multiplied by, / means divided by; short course is 25 yards or 25 meters, long course is 50 meters.)
A few very important notes about using converted times:
First, conversions will not always be exact. You must enter times which maintain the class for which you are qualified. When necessary (for example, when an A time short course does not convert to an A time long course), you should use the minimum qualifying time for the class you’ve achieved (in this example, a minimum A time) as your entry time.
There are a few situations where there are limitations on the use of a converted time for qualifying purposes. For example, if you are entering long course Far Westerns, a converted short course Q time does not automatically qualify you to enter an event. Your converted time must meet or exceed the listed long course qualifying time (Q time) for you to enter that event. Also, a converted short course time may not be used as a Western Zone Consideration Time (WZCT) — a WZCT must be a long course swim.
Converting short course yards times to meter times
Short course yards to short course meters:
Meter time = (yard time in sec.) * 1.1
Short course yards to long course meters:
When yard distance = meter distance, meter time = (yard time in sec. * 1.1) + T
( where T = the difference in the number of turns between short course and long course)
50 yard event to 50 meter event: meter time = (yard time in sec. * 1.1) +1
100 yard event to 100 meter event: meter time = (yard time in sec. * 1.1) + 2
200 yard event to 200 meter event: meter time = (yard time in sec. * 1.1) + 4
400 yard event to 400 meter event: meter time = (yard time in sec. *1.1) + 8
500/1000 yd free to 400/800 meter free: meter time = (yd time in sec. * 1.1 * .8 ) + T ( where T = the difference in the number of turns between short course and long course)
500 yard event to 400 meter event: meter time = (yard time in sec. * 1.1 * .8) + 12
1000 yard event to 800 meter event: meter time = (yard time in sec. *1.1 * .8) +24
1650 yard free to 1500 meter free: meter time = yard time + 30 seconds
Converting meter times to short course yards times
Short course meters to short course yards:
Yard time = meter time in sec. / 1.1
Long course meters to short course yards:
When meter distance = yard distance, yard time = (meter time in sec. – T ) / 1.1 (where T = the difference in the number of turns between short course and long course).
50 meter event to 50 yard event: yard time = (meter time in sec. -1) / 1.1
100 meter event to 100 yard event: yard time = (meter time in sec. -2) / 1.1
200 meter event to 200 yard event: yard time = (meter time in sec. -4) / 1.1
400 meter event to 400 yard event: yard time = (meter time in sec. -8) / 1.1
For 400/800 meter free to 500/1000 yards free, yard time = [(meter time in sec. – T) / 1.1] *1.25
(where T = the difference in the number of turns between short course and long course)
400 meter event to 500 yard event: yard time = [(meter time in sec. -12) / 1.1] * 1.25
800 meter event to 1000 yard event: yard time = [(meter time in sec. -24) / 1.1] * 1.25
For 1500 meter free to 1650 yards free, yard time = meter time – 30 sec.
Thanks to Si-Swimming
