Best ways to estimate refund with planned marriage

[TheEngineer]

My fiancé and I will be getting married in about a month. We have both been paying taxes if we were single filers. I have a substantially larger amount of income compared to my partner (I will make 5x their income be years end). 
With myself paying 5/6 of our joint income and paying as if I’m a single filer all year, and my partner doing the same for the other fraction, what is the best way to calculate the tax implications of being wed? There are other factors at play but I’d like to know what tools are recommended. 

I’ve tried using the tax estimator through Intuit but it doesn’t take into account the taxes we’d been paying as an input to the tax refund estimator. 

Additionally, if other tax incentivized activities (like insulating a house, purchasing an electric car, etc) were purchased there is not a convenient way to calculate the tax implications. Again, what tool is recommended for use? 

[carmen_t]

Congratulations and thank you for your question.  There are some benefits based on updating filing status.  You now have the options of married filing jointly (MFJ) and married filing separately (MFS).  Please keep in mind if you chose MFS if one itemizes the other has to and the same with standard deduction.    I will also recommend for both to update W4 forms at work to account for filing status and income.  I will include a 1040ES and tax estimator to help.  Have a great day!  

IRS 1040ES 

Tax Estimator