Mortgage rates are always in flux, changing daily, and even hourly, depending on market conditions.

According to a study from The Mortgage Reports and MBSQuoteLine, rates tend to fluctuate the most on Wednesdays and Fridays, varying as much as 24 basis points (0.24). They’re steadiest on Mondays.

These movements can pose a challenge if you’re in the process of buying a house. For example, you might apply for a mortgage, get quoted a 6.5% rate, and then, by the time you find your house, rates have jumped to 7%. This can mean a big difference in monthly payments and your overall loan costs.

To see how rate fluctuations can impact your mortgage, you can look at the rates at different points over the last year (see table below). The payment and total interest for each rate (on a $300,000, 30-year loan) are included. At the lowest rates in the table, you’d save $226 per month and over $81,000 through the life of the loan compared to the highest rates.

To control the flow of money and credit in the economy, the Fed sets the federal funds rate, a benchmark rate that affects the interest rates consumers pay on different types of loans and earn on their savings.

The federal funds rate doesn’t directly determine mortgage rates, but it impacts the yield on the 10-year Treasury note, which mortgage rates closely track.

Home loan interest rates are determined by a variety of other market factors, including:

• Overall economic conditions

• Financial markets as a whole

• Inflation

• Interest moves by the Federal Reserve

Yet, mortgage rates and the 10-year Treasury tend to move in unison. If the 10-year Treasury yield moves higher, mortgages typically do too — but with a margin of separation. Historically, the spread between the two has been between one to two percentage points. More recently, that spread has widened to over two percentage points.

For example, on April 24, 2025, the 10-year Treasury yield was 4.32%, and average 30-year mortgage rates were 6.81%.

Market conditions are only one factor that influences the mortgage rate you qualify for when you apply for a loan. And the rates seen above? Those are just averages.

Your rate will also be affected by:

• Your credit score: Your credit score and the score of any co-borrowers will factor in. Lower scores usually mean higher rates, while higher credit scores can help you snag a lower rate.

• Your down payment: If you’re able to make a large down payment — and borrow less from your lender — you'll usually get a lower interest rate in return.

• Loan term: The length of your loan also plays in, with longer terms carrying higher rates than shorter-term loans. For instance, the average rate on a 15-year loan as of May 7 was 5.92%. For 30-year loans, it was 6.76%.

• Type of loan and interest rate: Adjustable-rate mortgages often come with lower rates than fixed-rate loans at the start, but those rates can rise over time. Rates also vary by loan type with government-backed options like FHA loans boasting lower rates than conventional loans.

Rates also vary depending on the mortgage lender you choose. In fact, getting rate quotes from at least four lenders can help you save as much as $1,200 annually, according to Freddie Mac.

Rates change often and homebuying timelines can be hard to predict.

That’s where a mortgage rate lock can come in. With a rate lock, you’re able to secure your interest rate for a set period of time — usually somewhere between 30 to 60 days, depending on the lender. Once your rate is locked, it can't change, no matter what happens in the market, during that time frame.

Some lenders lock your rate from the outset, while others require you to request it. You also might need to pay a fee, particularly if you need a lengthy rate lock. (Some lenders offer locks of 120 days or longer.)

Be choosy about when you lock your rate and ask your lender about potential float-down options, which allow you to take advantage of lower rates if they drop during your lock-in period. Be sure to ask about any fees for float-downs too.

Knowing what impacts your mortgage rate can help you snag a lower one. Timing your application and rate lock right are good places to start. You can also reduce your rate by increasing your credit score and saving up for a larger down payment.

Choosing a shorter loan term, going with a government-backed loan program, and shopping around for your lender can also help secure a lower rate.

You can consider buying down your rate — or buying discount points. These are tools that let you pay a fee in exchange for a lower rate, either temporarily or for your entire loan term. In some cases, you may be able to negotiate for the lender, seller, or even your agent to pay these fees, though it depends on the market conditions in your area. (A seller may be more willing to do it if they’re desperate to unload the house and are in a strong buyer’s market, for example.)

Mortgage interest rates change daily, and sometimes even hourly, depending on market conditions. The rate you qualify for also depends on your lender, the home you’re purchasing, your financial details and credit, and other factors.

Banks and lenders change their interest rates daily or even hourly. The best way to ensure your rate doesn’t change is to get a rate lock, which secures your mortgage rate for 30 to 60 days, in most cases.

A 1 percentage point difference in mortgage rates can make a huge difference cost-wise. For example, a $300,000, 30-year mortgage at a 7% interest rate would come with a $1,996 monthly payment and over $418,000 in total interest. A 6% rate, on the other hand, would have a $1,799 payment and $347,515 in total interest.