# Renewal Calculator: Payment Shock & Switch vs Stay

> Prices the balance you will owe at maturity over the years left, so you see payment shock — and whether a switch beats staying — before the renewal letter does.

Category: Calculator
Last verified: 2026-08-29
Source: https://ratellow.com/mortgages/renewal-calculator

## TL;DR
- Stay is always untested. An uninsured straight switch has been untested since 21 November 2024. A refinance is always tested.
- The tool re-amortizes the maturity balance over remaining amortization at a renewal rate you choose — that difference is payment shock.
- Most lenders will hold a rate 120–180 days before maturity. Federally regulated lenders must send a renewal statement at least 21 days before the term ends.