Yeah but it&#x27;s not a 1:1.<p>i.e. a 50% smaller screen doesn&#x27;t use 50% less battery for the screen, let alone cut 50% battery.<p>For one, part of the screen is powered by a controller that&#x27;s pretty similar whether it&#x27;s a 4 inch or 5 inch screen. So if you cut the screen in half, you save maybe 40% battery going towards powering the screen.<p>But then the screen is only a fraction of the power usage, let&#x27;s call it half. So cutting the screen in half drops battery usage not by 40%, but 20%. And then the screen is off half of the time while the phone is still using battery, which is why it&#x27;s even lower than that.<p>So half as big a screen might reduce total battery usage of the phone by say 20-30% tops. And that&#x27;s without taking into account that  a big chunk of a phone&#x27;s internals are going to be non-battery (e.g. flash storage, cpu, ram) which don&#x27;t get bigger (or at least anywhere near 2x as big) if the screen is twice as big, and so the battery-to-volume ratio on a bigger phone is bigger than on a smaller phone.<p>In short, while yes obviously smaller phones have smaller screens that use less energy, overall bigger phones have better battery life because they have comparatively bigger batteries.<p>As for tablets vs phones comparison, it&#x27;s an apples&#x2F;oranges comparison as they do different things but, no way.<p>If you want to make the comparison, top iPad has a 42 watthour battery, iPhone 6 has 6.9. About 6x battery difference, despite the fact the 9.7 inch vs a 4.7 inch screen. That iPad has 3x as many pixels to power but 6x the battery to do it.<p>But again, it&#x27;s apples&#x2F;oranges.<p>Compare the iPhone 6 to iPhone 6 Plus. According to you the reason tablets get worse battery life is because they&#x27;re bigger and have bigger screens, which are the main battery sink. So the 6 Plus should have worse battery life, according to you under the same principle.<p>But it&#x27;s wrong, the iPhone 6 Plus has 60% more watthours of battery, despite being 32% bigger. And if you look at Apple&#x27;s references (usually pretty good), they rate for the Plus vs the standard iphone: 10 hours more talk time, 34 hours more standby, 2 hours more internet  time on 3G or LTE, 1 hour more on wifi, 3 hours more video playback and 30 hours more audio playback. Note the video (where the screen is one of the biggest battery sinks you can imagine), it&#x27;s got a battery lifetime of 27% more despite a 32% bigger phone, for all the above mentioned reasons that a percentage increase in screen size has a somewhat larger percentage increase in extra battery volume.<p>So I&#x27;d say that the notion that bigger phones have better battery life, in general, is true. And when choosing the plus version on the iPhone, the battery life is a benefit. While choosing say the mini version on android phones (even as they&#x27;re often underpowered, such as the Galaxy S mini series), tends to diminish battery life.