How many man-hours should I estimate for this iPad app?

Question

Background: I've developed an iPad/iPhone app of my own before. This will be my first app for a client. I have no experience estimating the number of hours it will take, since all of my prior iOS development has been off the clock.

I'd like to get a very general recommendation for how long it would take a knowledgeable iOS developer to develop a simple PDF-viewing app for a clients' existing PDF book series. For something of that scale, what would you ballpark-estimate your hours? 10 hours? 25? 50? 100?

I know estimates are hard to get right and it depends on the developer, having carefully-planned requirements, and the like. I will take those precautions and refine the estimate to better match well-outlined requirements. I'm a competent developer, I just don't know where to start in terms of estimating time.

Answer 1

This is very subjective. You'd need to look back and add up the hours you spent on your previous apps to get a idea. One thing I can lend you is take your estimate and add on 30% for unforseen issues.

A general PDF Viewing app shoudln't take too long depending on how fancy you want it to be. Is it a bare bones or will it have add on features? A basic Iphone app go with 25-50 hour marker (Roughly a week and change). Perhaps make it 80 Hours (Two full weeks) to give you some breathing room.

Once you're through your first week you'll have a better grasp of how much time you'll need.

Keep in mind my guess assumes you working alone doing only basic testing and validation and not including any client required test time or review time etc.

Answer 2

In the back of your head you have a gut reaction estimate in mind.

Take that estimate and triple it. Seriously, we developers are notoriously optimistic as a rule.

This sets a good base line with some padding.

Track it heavily and use the data to make future estimates.

Answer 3

You could break the app up into parts and time yourself for building one piece. Then it is a matter of how long will the other pieces take relative to your test piece. Example:

• Part A (test) 1.5 hours
• Part B 3 times as long
• estimate 4.5 hours.

Try to do the test under normal development times and you energy level.