Mortgage refinance calculator w/ additional principal payments?

[FIREintraining11]

Does anyone know of a good mortgage refinancing calculator that includes additional principal payments?  Or more specifically what the break even additional principal payment is between two rates?

I currently owe $87,000 on my house purchased for $137,000 in 2017.  My current mortgage rate is 4.00% for a 30 year loan.

Through credible.com’s refinance rates I can get a 15 year fixed mortgage for 2.625% + $5,000 in loan costs.

Asking because I started a new job in September at a lower salary and won’t be able to pay down the principal as aggressively as I have the past few years.

[ericbonabike]

this is what I've been using.
You can download the excel spreadsheet at the very bottom.

very nice.

http://www.tvmcalcs.com/index.php/calculators/apps/excel_loan_amortization_with_extra_payments

[DK]

https://www.bankrate.com/calculators/mortgages/amortization-calculator.aspx

[Sibley]

I have my own amortization schedule in excel.

[FIREintraining11]

this is what I've been using.
You can download the excel spreadsheet at the very bottom.

very nice.

http://www.tvmcalcs.com/index.php/calculators/apps/excel_loan_amortization_with_extra_payments

This worked great, thank you!

[stacheinprogress]

This is somewhat related to the question. I have used bankrate's refinance calculator to see if it would be worth it to refinance right now. Their calculator showed that refinancing would save $134k in interest over the life of the loan, evening with $9k in closing costs. However, when I put the same numbers into Zillow's refinance calculator, it showed that I would save just $60k in interest. Does anyone know why that might be?

[MDM]

Does anyone know why that might be?

One is correct and the other is incorrect?  Input error?

See http://forum.mrmoneymustache.com/real-estate-and-landlording/help-with-time-to-payoff-mortgage/msg1220054/#msg1220054 for a quick way (if you have Excel) to check.

[rab-bit]

I like this one:

https://financialmentor.com/calculator/mortgage-payoff-calculator

[Beach_Stache]

I love Karl's Mortgage Calculator: https://www.drcalculator.com/mortgage/
I have the app on my phone and when we would make extra payments I'd love to see how that would affect our end of loan date.  We refinanced in Nov 2019 so we don't pre-pay anymore since our rate is now 2.25% on a 15 year fixed, but I used the calculator to do the math to determine what the break even period was on refinancing with fees and how much we would ultimately save over time. 

[TomTX]

That sounds like a terrible refi offer.

Personally, I'd rather have cash/stocks than put extra money into a mortgage where it's hard to extract if you need it.