I have no experience and I'm looking at an older duplex (off market) that is basically gutted and has no electrical, plumbing, or ac. Do I have to have the house under contract before asking a contractor for an estimate on repairs?

No - you do not have to have it under contract. I would recommend setting an appointment and just let them know you want your contractor to look at it. The seller will actually feel like you are more serious as you are taking steps ahead of time to be prepared and cut down on time between acceptance and closing doing it ahead of time. 

@Rebekah Valdez

I do not think it is necessary however, I would want to be certain their are good chances the deal could go through to sure I am not wasting their time. This is more for the sake of your relationship to ensure you are not calling them for every property you walk through. 

After talking to a few of my local contractors it is much more preferred to bring them in during the inspection period, especially when first starting out. 

Thank you both, much appreciated. 

Catherine is correct. You don’t need to be under contract. When you call the contractor just be upfront with them and tell them what your plans are. They are not going to be able to give you and accurate estimate on the spot so be patient. Be concise with what you want done, your timeline, and what level of finishings. IE: high end, low end, durable, long lasting and so on. Make sure the contractor is reputable, preferably someone who has worked with investors before. Make sure he is licensed and insured.  Hope this helps. 

@Raymond Temprano

Thanks so much!

you should be able to inspect it with a contractor before getting it under contract. The key is gonna be finding a good contractor. You should aim to develop a good working relationship with one. 

Sometimes being in a trade gets busy and its hard to get out to give estimates for new customers on buildings they dont even own yet especially if they expect a free in depth estimate immediately. So generally we'll charge for an estimate on new customers that cold call us randomly for estimates (it weaves out a lot BS). Good existing customers are a different story because they have a track record and less likely to be a waste of time on the contractor end. 

You might do just as well to take an experienced house flipper with you for ballpark estimates.  Also, if you have to do major rehab to a place where the renovations exceed 50% of the current market value, a lot of cities will require to bring up the property to current code, which can add to your expenses to repair things you otherwise would not, such as making the place comply with energy code requirements and next thing you know you gotta replace the windows and insulation. But if the place is basically a complete gut anyway, then maybe that's not so much a big deal.

Thank you!