Weekly Mortgage Payment Index - PMMS Rate to $300k P&I

Track the weekly Freddie Mac PMMS 30-year rate as monthly P&I on a $300k loan. Free CSV download, cited methodology, updated after each survey week.

Rajkishor Sahu
By Rajkishor Sahu Software Engineer, Founder of Daily Calcs
· Published October 15, 2026 · 7 min read

How Much Do Mortgage Payments Rise When Rates Change?

When the Freddie Mac PMMS 30-year average moves, monthly principal-and-interest moves with it. On a locked $300,000 / 30-year loan, a 0.10 percentage-point rate change is roughly $20/mo of P&I in the mid-6% to mid-7% band. This weekly index converts each PMMS print into that comparable dollar payment so you can see week-over-week and year-over-year cash-flow impact - not a personalized Loan Estimate.

Last reviewed: · Sources: Freddie Mac PMMS via FRED; Daily Calcs amortization engine

Editorial note: National averages are planning context only. Your Loan Estimate depends on credit score, loan-to-value (LTV) ratio, points, product (conventional, FHA, VA, jumbo), and lender pricing.

Research method: Daily Calcs ingests FRED series MORTGAGE30US, commits a weekly JSON snapshot, and applies the same fixed-payment formula used by our Mortgage Calculator and Amortization Calculator on a locked $300,000 / 30-year loan. Lifetime interest assumes the rate holds for the full term with zero extra principal. Headline figures below refresh when the snapshot updates.

Weekly PMMS payment index · Snapshot verified

As of , the Freddie Mac 30-year PMMS average was 7.40%. On a standard $300,000 / 30-year loan, that implies about $2,077 per month in principal-and-interest (P&I only).

Week-over-week payment
$0
Rate 0.00 pts
Year-over-year payment
+$226
Rate +1.13 pts
2026 YTD avg rate
6.48%
~$1,892/mo P&I
Lifetime interest @ latest
$447,770
If rate held for full term

Freddie Mac Primary Mortgage Market Survey (PMMS). Data retrieved via FRED series MORTGAGE30US and MORTGAGE15US. Index loan: 20% down on a $375,000 purchase (loan amount $300,000). Download the full weekly series ( 2,899 observations) as CSV.

Last 52 weekly observations (newest first). Principal-and-interest only on a $300,000 30-year loan. Snapshot verified .
Week ending 30yr PMMS Monthly P&I Lifetime interest
7.40% $2,077 $447,770
7.40% $2,077 $447,770
7.28% $2,053 $438,949
7.03% $2,002 $420,704
6.95% $1,986 $414,904
6.76% $1,948 $401,204
6.71% $1,938 $397,617
6.66% $1,928 $394,037
6.65% $1,926 $393,322
6.67% $1,930 $394,752
6.69% $1,934 $396,184
6.66% $1,928 $394,037
6.58% $1,912 $388,325
6.55% $1,906 $386,189
6.49% $1,894 $381,923
6.43% $1,882 $377,669
6.49% $1,894 $381,923
6.47% $1,890 $380,504
6.52% $1,900 $384,055
6.48% $1,892 $381,214
6.53% $1,902 $384,766
6.51% $1,898 $383,344
6.36% $1,869 $372,720
6.37% $1,871 $373,426
6.30% $1,857 $368,491
6.23% $1,843 $363,570
6.30% $1,857 $368,491
6.37% $1,871 $373,426
6.46% $1,888 $379,795
6.38% $1,873 $374,133
6.22% $1,841 $362,869
6.11% $1,820 $355,172
6.00% $1,799 $347,515
5.98% $1,795 $346,127
6.01% $1,801 $348,209
6.09% $1,816 $353,777
6.11% $1,820 $355,172
6.10% $1,818 $354,474
6.09% $1,816 $353,777
6.06% $1,810 $351,687
6.16% $1,830 $358,666
6.15% $1,828 $357,966
6.18% $1,834 $360,066
6.21% $1,839 $362,167
6.22% $1,841 $362,869
6.19% $1,835 $360,766
6.23% $1,843 $363,570
6.26% $1,849 $365,677
6.24% $1,845 $364,272
6.22% $1,841 $362,869
6.17% $1,832 $359,365
6.19% $1,835 $360,766

What The Data Shows

Rate moves show up as cash-flow moves

A 0.10 percentage-point change on this index loan is roughly $20/mo of principal-and-interest in the mid-6% to mid-7% band. Week-over-week deltas look small; year-over-year deltas often matter more for household budgets and for stories that compare “this October” to “last October.”

Lifetime interest dwarfs the monthly print

Even when the weekly payment change is tens of dollars, locking a higher rate for 30 years compounds into tens of thousands of dollars of lifetime interest on the same balance. That is why the table shows both monthly P&I and lifetime interest side by side.

The index is a benchmark, not a quote

PMMS is a national survey average for a conforming 30-year fixed product. Borrowers with different credit, LTV, points, or government-backed products can see quotes well above or below the index. Treat it as a comparable time series - then re-run the Mortgage Calculator with your numbers.

Method And Limits

  1. Source: Freddie Mac Primary Mortgage Market Survey via FRED MORTGAGE30US (weekly since April 1971).
  2. Loan frame: $300,000 principal, 30-year fully amortizing fixed rate, monthly payments, no extra principal.
  3. Payment formula: Standard fixed-payment amortization (r/12 monthly rate). Same engine as our public calculators.
  4. Excluded: Taxes, insurance, PMI, HOA, points paid upfront, lender fees, and credit-based pricing adjustments.
  5. Refresh: pnpm rates:fetch updates JSON + CSV; a weekly GitHub Action can commit those files when FRED advances.

For decade-level narrative and an interactive chart, see Historical Mortgage Rates Chart. For year-by-year landmark payments, see Mortgage Rate History Payment Impact.

Official And Supporting Sources

Next Step

Download the weekly payment-index CSV, then plug your price, down payment, and quote into the Mortgage Calculator.

Frequently Asked Questions

What is the Daily Calcs weekly PMMS payment index?

It converts each Freddie Mac Primary Mortgage Market Survey (PMMS) 30-year weekly average into the fixed principal-and-interest payment on a standard $300,000 / 30-year loan. Holding the loan amount and term constant isolates rate as the only variable, so journalists and planners can cite one comparable dollar figure each week.

Does the index include taxes, insurance, or PMI?

No. The index is principal-and-interest only. Property taxes, homeowners insurance, private mortgage insurance (PMI), HOA dues, and closing costs are excluded so the series stays comparable across decades. Use the Mortgage Calculator with local tax and insurance assumptions for a full monthly housing cost.

Where can I download the full weekly series?

Download the CSV from this page (path /data/reports/pmms-30yr-weekly-payment-index.csv). Columns include week-ending date, 30-year PMMS rate, monthly P&I, lifetime interest, total paid, loan amount, and term years. The file refreshes when we re-run the FRED ingest (weekly automation when enabled).

How often is the payment index updated?

Freddie Mac typically publishes PMMS on Thursdays. Daily Calcs commits a JSON snapshot via FRED series MORTGAGE30US and regenerates the payment CSV in the same step. The verified date under the headline shows when the snapshot was last refreshed. National averages are not a personalized Loan Estimate.

Can I cite or republish this payment index?

Yes. Use the citation block on this page. Credit Freddie Mac PMMS as the rate source, link back to this URL, and note that payments are modeled on a fixed $300,000 / 30-year loan. Dataset JSON-LD identifies the temporal coverage, creator, and CSV distribution.

How does this differ from the historical rates chart?

The historical chart emphasizes the full PMMS rate path (30-year and 15-year) with decade tables. This index is the citeable weekly dollar series - latest week, week-over-week and year-over-year payment deltas, YTD averages, and a downloadable CSV of every weekly observation since 1971.

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