Mortgage Excel Spreadsheet

What this does

PMT returns the fixed monthly payment that fully repays a loan — principal plus interest — over its term. It assumes a constant rate and equal payments, which is how the overwhelming majority of mortgages, car loans and personal loans are structured. Dividing the annual rate by 12 and multiplying the years by 12 puts everything on a monthly footing; the negative sign on the amount makes the payment show as a positive number. The same idea underpins a lot of everyday Excel work, so the few minutes spent getting it right here pay back across every sheet you build afterwards. Treat it as a pattern, not a one-off, and it stops being something you look up and starts being something you reach for. Treat “mortgage excel spreadsheet” as a small repeatable workflow rather than a one-off click you hope to remember next time. Use a small test block before the live file, so any surprise in the affected sheet shows up while it is still harmless. When a formula is involved, keep the inputs labelled beside it, reference cells instead of typing values, and apply number formatting only after the result checks out. That turns a calculation you can defend to a CFO or an auditor into a method you can reuse, explain, and defend when the workbook leaves your screen.

A worked example

A €250,000 mortgage at 3.8% over 25 years: =PMT(3.8%/12, 25*12, -250000) returns about €1,292 a month. Over the full term you repay roughly €387,500, so interest alone is about €137,500 — the area the balance curve above shrinks as you shorten the term or drop the rate. Whether you are comparing mortgage offers, sizing a car loan, or stress-testing a budget against a rate rise, PMT is the one formula that turns a headline rate into the number that actually hits your account each month. If there is any chance you will reuse this, drop it into a small template tab right now: a labelled input area on the left and the formula beside it, checked once against the tool above. Next time the same question comes up, the answer is a single paste away instead of a rebuild from memory.

In Google Sheets

Google Sheets handles this almost identically to Excel. The formula syntax above is the same, and the menu lives under a slightly different label rather than a ribbon tab. Use the platform toggle at the top of the page to switch every keyboard shortcut between Windows and Mac, and expect at most cosmetic differences in naming. Keep this page bookmarked for the next time the same question comes up. Better still, rebuild the example once in your own sheet — doing it yourself, with the tool above to check against, is what turns a copied formula into a technique you own. Treat “mortgage excel spreadsheet” as a small building block rather than a chore. Once the inputs sit in their own cells and the formula reads from them, the same setup answers a dozen related questions with a tweak, and Excel keeps every dependent figure current as the data changes. The tool above is there so you can rehearse and verify before committing anything to a real workbook; the steps and worked example are there so the logic sticks. Get it right once and it stops costing you time — it starts saving it, every time the question comes back around.

Common mistakes

• Forgetting to divide the annual rate by 12, which inflates the payment roughly twelve-fold.
• Entering the loan amount as positive, so PMT returns a negative payment.
• Mixing the term and rate periods (annual rate with a monthly term, or vice versa).
• Ignoring fees, insurance or an offset, which the bare PMT figure does not include.

Frequently asked questions