In the sport of powerlifting, your lifts are measured in kilograms.
The bar weighs 20 kilograms, or 44.1 pounds. So the lightest weight you can attempt is 20kg, and we go up from there, in multiples of 2.5 kilograms (or about 5 1/2 pounds).
Kilogram-pound conversion charts, like the one below, will usually be available throughout your event venue. If not, download one ahead of time or bring a print out with you.
Openers
When you weigh in, you’ll submit your opening attempts for squat, bench and deadlift.
Decide on these numbers ahead of time. If you are a first-time competitor, I recommend you select an opening attempt between 85-90% of your 1RM (assuming your 1RM is a legit number, judged by strict standards like full squat depth, a 3-second pause at your chest on bench, practicing commands, etc).
If you are very nervous about competing, or unsure about your range of motion or referee commands, choose an even lower starting attempt.
One good rule of thumb for your opening attempts: choose a weight you can do FOR A TRIPLE in the gym on your very worst day. If you slept like poo, your nutrition is off, your head hurts and life sucks, what weight can you still lift for three legit reps, without a doubt?
THAT is your starting attempt.
Your openers are not set in stone until 3-5 minutes before your flight begins that lift (this varies by federation so pay attention at the Rules Briefing).
Let’s say you’re in Flight C and when you start warming up squat it is feeling heavier than usual. If Flight B is still squatting, you can go to the scorer’s table and ask them to adjust your opening attempt, as long as there is still more than 3-5+ minutes remaining in Flight B.
Other attempts
There are many philosophies on attempt selection for a powerlifting meet. Most coaches agree the first attempt should be in the 85-90% range, attempt 2 should be 95-98%, and attempt 3 should be 100-103%. Of course there are lots of variables (your energy level, mental state, goals for the meet, podium contention, etc) that might change your game plan. Do your best and have some fun.
Whenever you take the platform for your first meet, I wish you lots of PRs and white lights.