Will the Republican Tax Bill make you pay more or less in taxes?

House and Senate Republicans have passed a major tax bill. The bill makes big changes to how the government taxes its citizens. Most notably, corporations and some individuals will pay less tax (corporate rate lowered to 21%, lower individual brackets, higher standard deduction), but many deductions like the state and local deduction and personal exemption will be limited to pay for it and the deficit will likely go up.

How would this affect you? Is the backlash against certain Republican lawmakers in high tax states like California fair? Do I sense a spreadsheet in the making? After 3 prior tax posts including How to Estimate Taxes, a Marriage Tax Penalty Calculator, and an analysis of the Trump Tax Plan, you would think we had suffered enough…but here we go!

Sneak Peak – Our results indicate that married Californian homeowners making under about $700k are better off under the new plan, while those making over $700k are worse off. Disclaimer – this is really complicated, we might have made some errors (please let us know if you see any), and your mileage may definitely vary:


Spreadsheet Inputs and Simplifications

Calculating the effect of tax changes is remarkable complex – we’ll be making a lot of assumptions. We’ll focus on a married couple, set kids as an input variable, and focus on the impact of just the major changes: new brackets, limitation of the state and local tax deduction, AMT changes, and higher standard deduction/elimination of the personal exemption. We’ll ignore some complicating factors that we think have a smaller impact – that is the essence of modeling!

Our spreadsheet inputs include:

We start with cells for the user to enter their Adjusted Gross Income, mortgage interest paid, property taxes paid, and charitable/other deductions:


Current tax brackets and new tax brackets proposed under the tax plan. These are entered similarly to our past tax posts:

The standard deduction goes from $12,700 to $24,000

Personal exemptions that existed before would go away. We’ll have a space to enter personal exemptions (4 for our hypothetical family):

Okay, here’s where it starts to get complicated. The state and local tax deduction goes away, We need to add in a section that calculates state and local tax. We’re going to assume you live in California and add in those brackets

And adding even more complication, to really make this fair, we needed to include an AMT calculation, as many higher earners in CA were likely to fall under the AMT. The thresholds for AMT changed, but AMT still exists after the tax bill (despite certain promises…).

Spreadsheet Logic

Okay, usually we walk step by step through how we built the spreadsheet. This spreadsheet was pretty complex and this part would have taken up an inordinate of space (and brain damage). To learn about how we did it, just open the file and walk through some of the formulas…basically we calculated CA tax due, then calculated federal tax due under the two systems, then AMT due under the two systems, then added the updated child tax credit (Thanks, Marco Rubio..). Hopefully we didn’t make too many errors, let us know in the comments how you’d do it differently!

Download here: Will Californians pay more or less taxes under the new Republican Tax bill?


How to compare rewards credit cards with the NPV() function

In this post, we’ll show you how to compare different credit cards that have different sign-up bonuses, annual fees, rewards, etc. We’ll use the NPV function, which allows us to compare different streams of cash flows that come at different times.

A word of caution: Our post assumes that you’ll pay off your credit card in full each month. As we mentioned in our personal finance modeling post, the rate of return earned on investments is one of the key factors in achieving long term financial independence. We assumed getting a 4% return on our investments…the average interest rate you’d have to pay on a credit card balance is 15%! That’s like having a huge negative investment, which could keep you in the poor house.

Image result for suze orman credit card debt Continue reading “How to compare rewards credit cards with the NPV() function”

What’s the expected value of your Powerball ticket?

As the Powerball jackpot grows to over $300 million, we start to wonder if maybe buying a ticket is “worth it.” While the lottery is “worth it” in that ticket sales goes to things like state education, buying tickets is typically not worth it for yo because the projected payoff is far less than the ticket price. Continue reading “What’s the expected value of your Powerball ticket?”

How much money do you need to retire?

As mentioned before, we love browsing through the questions and answers on Quora. Every Quora session reveals financial success stories, inside views into jobs and companies, and some practical life advice.

One topic that comes up frequently is how much money one needs to stop working. That is a question that spreadsheets are well-suited to solve! Let’s build our Financial Freedom Spreadsheet Calculator. Continue reading “How much money do you need to retire?”

Build a weighted lottery spreadsheet to decide on lunch with friends

Taking a walk and grabbing lunch is one of the simple pleasures of the workday. Unless of course, you bring your lunch to work. Sometimes with a group of people it is hard to decide on where everyone should go to lunch together. Maybe only one person enjoys the guilty pleasure of Taco Bell, while the others want to stick with Whole Foods. Or maybe half of the group wants burgers and the other half pizza.


Here’s a relatively simple Google Mobile spreadsheet. It’s part 2 of our mobile phone spreadsheet series (See Part 1 on Tracking New Year’s Resolutions) that uses a weighted lottery to fairly determine where to go for lunch, taking into account each person’s individual preferences. Basically, each person gets 10 “points” to allocate to three restaurant choices. Each point is effectively a lottery ticket, and the spreadsheet randomly chooses the restaurant, with the probability weighted by how many points each restaurant has received. Continue reading “Build a weighted lottery spreadsheet to decide on lunch with friends”

Track New Year’s Resolutions on Mobile Sheets

This is the first in a series of posts focused on the Google Sheets app on our mobile phone, rather than the typical desktop spreadsheets. We use the mobile Google Sheets app to set our New Year’s Resolutions and track what percentage of days we have fulfilled our promises. Hopefully, having this tracker on our phone and nearby at all times makes it slightly easier to fulfill our resolutions! Continue reading “Track New Year’s Resolutions on Mobile Sheets”

Keep New Year’s Resolutions with Spreadsheets

new-year-hatWhat are your new year’s resolutions? As in most cases, coming up with the goals is easy…but achieving them is another story! According to a Forbes article published a couple of years ago, only 8% of Americans achieve their resolutions. How can we keep our resolutions? Can we be better at goal-setting? As an organizational and prioritization tool, spreadsheets can keep us accountable and help us reach our goals. In our busy lives, it can be a challenge to keep track of and prioritize everything we set out to do. Spreadsheets can help by making us better managers of our lives. Continue reading “Keep New Year’s Resolutions with Spreadsheets”

What makes a good business? Part 3 of the IRR trilogy

This post was inspired by reading a Quora response where the child of a top 1% family says that one of the advantages of his upbringing is that his parents taught him about how business works. “Business” is a somewhat broad term that some schools say takes two years and $120k in tuition to “master”. However, as we typically do in this blog, we can educate ourselves on some of the central concepts of business on our own through spreadsheets!


Our hope is that anyone with internet access can find this page and play around with spreadsheets to begin to think about what makes a good business. Now if only this site could also provide the exotic travel experiences, connections, and the ability to take risks with a safety net that growing up in the 1% also provides… Continue reading “What makes a good business? Part 3 of the IRR trilogy”

Make a Buy vs Rent calculator spreadsheet

Is it better to buy or rent a house? Advice on this problem comes in all shapes and sizes, from the dogmatic idea that homeownership is the American dream, to some more nuanced methods like calculating the price to rent ratio. What would you do if you found a great house and are deciding whether to buy it or keep on renting?house-435618_1280
Continue reading “Make a Buy vs Rent calculator spreadsheet”

Is medical school “worth it”? An introduction to Internal Rate of Return (“IRR”)

Finance hiring is down, law school grads are having a tough time finding real law jobs, so what is an ambitious but risk averse college student to do with his or her life these days? Okay, right now the answer is computer science. Yes seriously, do computer science. But let’s pretend it is the year 2001 and the only other option respectable option is medical school. But doesn’t med school take a lot of time (4 years school plus 3-7 years residency/fellowship) and cost a lot of money? How can we figure out if going to med school and not earning doctor money until 7 years from now is worth it financially relative to just entering the workforce and working for those 7 years? Continue reading “Is medical school “worth it”? An introduction to Internal Rate of Return (“IRR”)”

How to analyze a nonprofit Form 990 with a spreadsheet

“The more you give, the more you get, that’s being alive” – The Money Song, Avenue Q

Charitable giving serves a valuable purpose  in  our society. It allows organizations in health, education, social services and others to provide benefits to people who otherwise couldn’t afford them. It allows people who have built up wealth to give back and make a difference. The federal government even subsidizes charitable giving by allowing donations to be deducted from income reported for taxes (effectively kicking in up to 39.6% of each donation). It’s a great system that is meant to fund those people and organizations in need. At least that is how it should be. Continue reading “How to analyze a nonprofit Form 990 with a spreadsheet”

Build a Spreadsheet to help you choose a healthcare plan

Will you save more with standard PPO or a high-deductible PPO Saver plan with a Health Savings Account?

It is currently Open Enrollment season at many workplaces, which is when employees choose their medical insurance and other benefits plans for the upcoming year. It’s also the time of year when people grumble “why is the US healthcare system so complicated” and just elect whatever plan they had in the prior year. Building a spreadsheet can help someone compare the costs and benefits of each of the plans under a variety of different assumptions about tax rate and healthcare expenditure. Continue reading “Build a Spreadsheet to help you choose a healthcare plan”