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Estimate the cost of storing google photos on the photos app?

estimation Guessestimation Market sizing
New answer on Apr 30, 2020
3 Answers
2.7 k Views
PK asked on Apr 10, 2020
Director of Product at PayPal. Based in SF. Worked at Twitter, Yelp, Salesforce, Houzz in the past.

Clarifying questions:

  1. Google photos - an app that syncs automatically to your camera app and uploads photos to Google cloud and reduces the need to store it on your device

  2. Cost of 1GB storage $0.002

  3. Time storage cost per year

Equation:

Cost of storage per year = average cost of storing photos per day x 30 days x 12 months

The average cost of storing photos = # of photos uploaded per day x average size of photos x $0.002/GB

# of photos uploaded per day:

Photos from developed world + developing world + underdeveloped world.

Total world population 7B, 50% have access to the internet. → 3.5B.

70% of those users use smartphones with camera and the majority of them are android users. → 2.1B.

Assuming 60% of these are android users → 1.2B Android devices that have Google photos app

Assuming 40% of iPhone users use google photos → ~300M iphone users use Google photos app.

Thus we have about 1.5B total google photos app users.

Breaking down the usage of camera and photo upload by the market:

  1. Developed countries - Assuming users take around 10 photos per day on average with high end cameras. Average photo size 4MB.

  2. Developing countries - Assuming users take around 5 photos per day with a medium to high end cameras. Average photo size 4MB

  3. Developing countries - Assuming users take around 2 photos per day with a medium to high end cameras. Average photo size 2MB

% of world in developed world ~ 20%

% of world in developing countries ~ 60%

% of world in developing countries ~ 20%

Assuming the same distribution holds across smartphones too:

Google photos users in developed world ~ 20% → 300M

Google photos users in developing countries ~ 60% → 900M

Google photos users in developing countries ~ 20% → 300M

The total size of photos stored per year:

  1. Developed - (300M x 10 photos/day x 4MB x 30 days x 12 months)--> 4.3 x 10^18 Bytes

  2. Developing - (900M x 5 photos/day x 4MB x 30 days x 12 months) → 6.4 x 10^18 bytes

  3. Under developed - (300M x 2 photos/day x 2MB x 30 days x 12 months) → 0.4x10^18 bytes

Total storage ~12 x 10^18 bytes -->12 x 10^9 GB

Total cost → 12 x 10^9 x $0.02 → $24 x 10^7 → $240M

This would be the cost for just one data center, assuming Google has atleast 5 data centres where this data gets replicated, it will be close to 240M x 5 --> $1.2B!

(edited)

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Best answer
Axel
Expert
Content Creator
replied on Apr 10, 2020
Bain Consultant | Interviewer for 3 years at Bain |Passionate about coaching |I will make you a case interview Rockstar

Hi PK,

Your approach makes sense but you are not considering one important driver of required storage which would be the number of photos that are being deleted on a daily basis. It may not make a huge difference but maybe reduces the required storage by 5-10%. I do think it should be included in an ideal answer though to show you have a comprehensive answer!

Best,

Axel

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Clara
Expert
Content Creator
replied on Apr 10, 2020
McKinsey | Awarded professor at Master in Management @ IE | MBA at MIT |+180 students coached | Integrated FIT Guide aut

Hello there!

To me the logic makes sense -this is what matters- but the assumption of photos/day in the 3 types of countries layed out seems very very high.

Take into consideration that is not only pics that are taken, but those than then are chosen to be stored -e.g., even if you make 10 pics at day, that it´s a way too high average, not all of them are good and relevant, so you don´t save them (particularly when u are paying for it)-.

Hope it helps!

Cheers,

Clara

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Antonello
Expert
Content Creator
replied on Apr 30, 2020
McKinsey | NASA | top 10 FT MBA professor for consulting interviews | 6+ years of coaching

Hi, I think it is a good approach. Always try to stay in 20 minutes and - if needed - accelerate some estimations by asking to the interviewer

Best,
Antonello

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