An estimated one-rep maximum is calculated from a recorded set. It is not a maximum you have demonstrated.
Check the input
The exercise, weight and actual repetitions must describe the same set. Mixed units or copied targets make the estimate misleading.
Keep comparisons consistent
Different formulas and exercise variations can produce different estimates. Compare like with like and inspect the source set behind a change.
Do not turn an estimate into a prescription
A model output does not establish a safe attempt or assess readiness. This page explains estimates; it does not provide a tested maximum or identify the formula used by the app.
Keep estimates distinct from completed lifts
If a calculator estimates a one-rep maximum from a multi-repetition set, label the result as an estimate and retain the original set beside it. Different formulas can give different outputs from the same input. The estimate does not prove that the predicted load was lifted, nor that attempting it would be appropriate. A chart should not cause a calculated value to replace a historical fact in your records.
Compare the inputs as well as the outputs
Check that the exercise variation, load convention and formula are the same across the entries you compare. A result based on a different machine or method may not belong in the same series. Read the calculator’s stated assumptions and avoid extrapolating beyond them. This page does not claim a particular undocumented formula for Weights or prescribe a maximal attempt; use the actual recorded sets as the underlying evidence.