I'm going to break my response down into 2 recommendations, because there are 2 phases of estimating costs that require different "apps".
- Quick Estimates/Rough Calculations
- Detailed Estimates
Quick Estimates/Rough Calculations using the Human Brain/Calculator/Notepad
When you are first evaluating a deal you need to be able to roughly estimate costs as quickly as possible to determine if the property is a good deal and if you should make an offer.
As other's have suggested, the human brain is great at quickly making rough calculations. Experienced investors can walkthrough a property and quickly tabulate rough costs of the major renovations in their head.
Example:
Roof $5k, kitchen $15k, bathroom $5k x 2, flooring x $3/sf, etc, etc.
This rough math can all be done using the human brain, a calculator or notepad to help you quickly evaluate a deal without fumbling around with a spreadsheet or an "app".
Detailed Estimates using Spreadsheets/Software
The problem with the human brain (mine at least), is my brain tends to forget things, so after I walkthrough a property I like to go through a checklist to make sure I didn't forget anything.
I also like to put my estimate information in spreadsheet/software to document all of the repairs for future reference.
Eventually, once I get the property under contract I will need to give this detailed estimate and SOW information to my business partners, lenders, Contractors, etc.
I will also use my detailed estimate as a reference for managing my budget during construction.
A good spreadsheet or software can help streamline this process so you aren't losing all of this data in your brain/calculator/notepad.
Spreadsheets
To start, you should really create your own custom spreadsheet with all of your typical repair items and prices that you can use as a checklist.
Your spreadsheet should have a list of all of your labor prices that you pay your contractors in your local market, and it should also include material prices for your specific materials you use in your projects.
Estimating Software/App
There are estimating apps/software that streamline the estimating process that have additional benefits like:
- Ability to save your own custom estimate templates with your own pricing, SKUs, etc
- Ability to make material selections and include exact material SKUs in your estimates
- Ability to create shopping lists for your project materials
- Ability to create estimate reports/SOW detailing your estimated costs in a professional report
- Ability to create SOW documents for your Contractors telling them exactly what they need to include
- Ability to track and compare your actual costs against your estimates
These are all things the human brain can't do, which is why I tend to do the detailed estimates in a spreadsheet/software.