I recommend a different approach. Charge your laptop to 100%, unplug it, fire up a movie in VLC, loop the movie so it plays forever, and use a stopwatch to see how long it takes your battery to drain.
MacBook Air vs. MacBook Pro; some MacBooks last longer than other configurations, depending on the chip, battery size, and other variables. The 16-inch MacBook Pro has a 100-watt-hour How long should MacBook Air 2015 battery last? The latest upgrade of the 13-inch Apple MacBook Air brings a more powerful Core i5 processor and an astounding 17.5 hours of battery life. It remains our top choice for ultraportable laptops. How long will 15 battery last on Mac? With the introduction of the MacBook Pro “Core Duo” 2.16 17-Inch on April 26, 2006, Apple reported that the battery life of the 17-Inch model was 5.5 hours, and that the 15-Inch models provide 4.5 hours of battery life, officially confirming the earlier speculation. MacBook Pro 16-inch 2019 Battery Draining while plugged in Upgraded from a 2018 MacBook Pro 15-inch. Same software, same daily use of zoom for meetings but this new MacBook drains the battery like never before. Can only run for about 5 hours of zoom before it drains from 100% down to 5%. The new 13-inch MacBook Air lasted 12 hours and 13 minutes, 23 minutes longer than our previous 13-inch MacBook Air. Not quite as large of a change as the official Apple estimates, but it also should be emphasized that these unofficial test results actually demonstrate longer battery life than the official numbers. They also offer exceptional battery life. As revealed by our Tom’s Guide battery tests, the 14-inch MacBook Pro with an M1 Pro chip can last 14:08 hours (with ProMotion refresh rate). The M1 Max Cz7Q.