Does cutting weight for a powerlifting weigh-in hurt your total?

Short answer

Not within 5%. In a study of 26 people who cut 4.81% of body weight and lifted 2 hours after weigh-in, the 3-lift total held steady and the body-weight-adjusted score rose 3.83%. The cost was fatigue and stress.

Does cutting weight for a powerlifting weigh-in hurt your total?
'Less body weight → less strength → lower total' — does this formula hold?
Powerlifting is contested in weight classes. So lifters often drop weight fast in the days before weigh-in to compete one class lower. We checked whether this cut takes away from the total.
How much do lifters cut?
More than 8 in 10, about 3% on average
In a survey of 321 lifters, 85.8% cut weight fast before competing, losing 3.0% of body weight on average. Among 64 world championship lifters, 83% cut an average of 2.9%. For an 80 kg (176 lb) person, that is about 2.4 kg.
Lose water, lose strength
Strength fell 5.5% on average
An analysis pooling 28 studies found that when people were tested low on body water, their strength dropped 5.5% on average. Losing water by sweating through exercise cut performance 5.4% more than losing it passively, as in a sauna.
But after weigh-in, you refill
After recovery, performance matched pre-cut levels
An analysis of combat-sport studies found maximal strength dipped slightly right after a fast cut. After 3-36 hours of eating and drinking post weigh-in, performance was no different from before the cut.
Powerlifting gives you 2 hours to recover
The 3-lift total still held
26 people were split, and one side cut 4.81% of body weight over 4 days by adjusting food, carbs, salt and water. At a mock meet 2 hours after weigh-in, their 3-lift total went from 540 kg to 538 kg, no change. It was also no different from the side that did not cut (534 → 537 kg).
The body-weight-adjusted score went up
Same weight lifted with a lighter body
In the same study, the score that accounts for body weight (IPF GL) rose 3.83% in the cut group and fell 1.23% in the no-cut group. In a study where 11 weightlifters ate 41.8% less for 6 days and lost 4.34% of body weight, their lifts did not drop either.
The cost showed up outside the total
Fatigue, stress and stalled progress
In the study of 11 weightlifters, the group that held its weight lifted more, while the cut group stayed flat. Among 64 world championship lifters, 91% had their mood worsen during the cut. A study of 53 lifters found that the more they cut, the worse their stress and recovery scores.
Summary: within 5% and 2 hours of recovery, the total did not suffer
Fatigue and stress came along instead
In the study where lifters cut about 5% and recovered for 2 hours, the 3-lift total did not drop and the body-weight-adjusted score went up. For an 80 kg person, that is about 4 kg. The cost was fatigue and stress, and it grew with bigger cuts. Cuts beyond 5% were not tested.