Estimating Google's Storage Bill for the Photos Users Back Up to Google Photos

Google Photos backs up the photos people take on their phones to Google's servers. Estimate how much it costs Google to store those photos. Set up an equation, label every assumption, work through the arithmetic and check whether your answer is plausible. ```hint Volume times unit cost Treat this as an amount of data multiplied by the cost of holding it. Size the data from the people who back up photos and how many each one adds, and think about what keeping a gigabyte for a year costs Google itself before you pick a price. ``` ### Clarifying Questions - Should the answer be a yearly cost, and should it cover only the photos uploaded this year or the whole library stored since the service began? - Is this worldwide or for one market? - Photos only, or videos too? A video is far larger than a photo. - Does "cost" mean raw storage only, or also redundant copies, network transfer and processing such as thumbnails and search indexing? ### What a Strong Answer Covers - An equation that separates users, photos per user, average stored size and cost per unit of storage. - A user count built from a defensible base, such as smartphone users and the share of Android and iPhone owners who back up to the app, with each figure labeled as an assumption. - User segments by how many photos they take, plus a deliberate choice between one year of uploads and the accumulated library. - A realistic unit cost for storage Google runs itself, including redundant copies, rather than a retail price taken at face value. - Correct unit conversions and arithmetic, and a sanity check against an independent figure. ### Follow-up Questions - How much would the total change if videos were included, and why? - Which single assumption moves your answer most, and how would you narrow it down? - How would you use this estimate when deciding how much free storage to give each account?