Minimizing your income tax bill is an important part of your financial plan.  Many physicians either coming out of residency or moving from an employed position to one as an independent contractor or partner aren't aware of the need to pay quarterly estimated taxes.  Even worse, many doctors don't realize the difference between the amount of taxes that are withheld and the amount owed.  These numbers can be quite different.

What You Need to Know about Estimated Taxes and the Safe Harbor Rule

Taxes Withheld Do Not Equal Taxes Owed

I always get a kick out of people excited to get a big tax refund.  “Tax refund sales” pander to the financial ignorance of our nation.  These fools rejoice in the fact that they got to loan the government their own money interest-free for a period of up to 16 months!

Instead, your goal ought to be to pay as few of your taxes as possible until the last possible moment without owing any penalties or interest.  An employee does this by selecting an appropriate number of allowances on his Form W-4.  An independent contractor or a partner does this by paying an appropriate amount with his quarterly estimated tax payments.  But either way, the amount withheld or sent in with estimated tax payments may have little to do with the actual amount of taxes owed at the end of the year.

Quarterly Estimated Payments

Since no one is withholding your taxes anymore, you are responsible to pay them yourself.  This includes your federal income taxes, your payroll taxes (Social Security and Medicare), your state income taxes, and if incorporated, your state and federal unemployment insurance payments.

These quarterly payments must be post-marked by April 15th (of the current year), June 15th, September 15th, and January 15th.  State deadlines often differ slightly and the payments are sent to the state tax commission instead of the US Treasury/IRS, but the principle is the same.  Instructions for how to do this can be found on IRS Form 1040-ES.

safe harbor ruleThere are a few exceptions to the need to make payments, but most doctors don't meet them, except possibly in their first year as an independent contractor/partner.  To avoid making quarterly estimated tax payments you need to either owe less than $1000 total for the year (fat chance of that), have had 100%-110% (requirement is higher if you have more than $150K of income) of what you owed the previous year already withheld prior to transitioning from employee to independent contractor, or have already had 90% of what you owe for the current year withheld.  I came very close to this situation this year (my first making estimated tax payments) so I know it is quite possible for a doc.

The 3 Big Tax Mistakes

There are three big mistakes to avoid when paying taxes.

#1 The first, least serious mistake, is to pay your taxes earlier than you have to (or pay more than you owe in the first place.

#2 The second, more serious mistake, is to not pre-pay a high enough percentage of your taxes and thus owe penalties and interest (not to mention the taxes themselves.)

#3 The third, and most serious mistake that commonly gets people into tax trouble with the IRS, is to spend your tax money on something besides taxes, so that when April 15th comes around you don't actually have the money to pay the taxes.

Understanding the safe harbor rules will help you avoid the first two problems.  Understanding the tax code and being disciplined will help with the last.

Safe Harbor Rules

The tax system is a pay-as-you-go system.  You can't just wait until April 15th and pay your tax bill.  If you do you'll owe penalties (1/4 to 1% of the amount owed for each month it is owed) and interest (at the rate of the federal short-term rate– currently around 0.25%- plus 3%).  But you can make a big payment on April 15th without paying penalties or interest IF you qualify under one of the following safe harbor rules.

  1. You didn't owe any tax at all last year.  (Good luck with this one.)
  2. You underpaid by less than $1000.  (So basically you never want to pay that last $1000 you owe early.)
  3. You underpaid by less than 10% of what you owe this year. (Again, no point in ever paying more than 90% of your tax bill prior to April 15th.)
  4. You paid in, either through witholding or via estimated tax payments, at least 100% (110% if you made over $150K) of what you owed last year.  (More on this below.)

You may also be able to avoid the penalties (but not the interest) if your underpayment was due to disaster, casualty, other unforeseen circumstance, disability or even retirement, if you can show the underpayment was due to reasonable cause and not willful neglect.

The 110% Rule

Estimating your taxes isn't necessarily easy, especially when you have a variable income like most physician independent contractors or partners.  Doctors rarely qualify under rule 1, and rules 2 and 3 require you to somewhat accurately estimate your current tax bill.  So rule 4 is really the only safe harbor that most physicians can actually count on.  Take what you owed last year, multiply it by 1.1, then divide it by four, and send in a check for that amount every quarter.

If you transitioned from an employee position midway through the year (like most docs), it can be even trickier.  You take what has been withheld so far for you, subtract that from the amount owed last year multiplied by 1.1, divide by two, and send that amount in on September 15th and January 15th.

Unequal Payments

So, you're thinking to yourself, why not just send in all the money on January 15th?  Unfortunately, the IRS is one step ahead of you.  Your payments throughout the year have to be related to your income throughout the year, as you can see on Form 2210.  Interestingly, if you have the money withheld by an employer, it doesn't matter when it was withheld.  You can claim 50 allowances all year, then claim 0 in November and December, and if you otherwise fall into the safe harbor rules, no penalties or interest are owed!

Remember To Keep Your Tax Money Safe

If you pay less than you owe, either deliberately or accidentally, be sure to keep enough cash on hand to pay those taxes come April.  Remember that taxes withheld/pre-paid may have little to do with the taxes actually owed, and come April 15th, you've got to square the accounts.