A rate change turned into dollars on your own balances.
Who this is for: Turning an FOMC decision into dollars on your own balances.
Fed funds target 3.75–4.00% since September 17, 2026
pts
$
%
$
%
$
%
$
%
%
How it is worked out
1Card and HELOCbalance × change ÷ 12, e.g. $6,000.00 × 0.0025 ÷ 12 = +$1.25
2Adjustable loanlevel payment at 7.25% − at 7.00% over 300 months = +$48.08
3Netdebts +$57.67 − savings +$4.17 = +$53.50 a month
Before and after, a month
Line
Rate after
Before
After
Change
Credit card interest
22.25%
$110.00
$111.25
+$1.25
HELOC interest
8.75%
$283.33
$291.67
+$8.33
Adjustable-rate loan payment
7.25%
$2,120.34
$2,168.42
+$48.08
Savings interest earned
4.25%
$66.67
$70.83
+$4.17
Calculated in your browser — the numbers you enter are never sent to our servers.
See what the Federal Reserve’s latest quarter-point increase, or any rate change you enter, does each month to a credit card balance, a HELOC, an adjustable-rate loan and the interest your savings earn.
Best for: After an FOMC decision, Card and HELOC balances, Adjustable-rate loans, High-yield savings
Updated September 2026 · Estimates only, not financial advice.
The Fed raised its range to 3.75%–4.00% on September 16, 2026
The Federal Open Market Committee raised the target range for the federal funds rate by a quarter point, effective September 17, 2026. The Board raised the primary credit rate to 4.0% and the interest paid on reserve balances to 3.90% at the same time.
The federal funds rate is what banks charge each other overnight, so nobody pays it directly. It reaches households through the rates that are set from it: variable card and HELOC rates that follow the prime rate, adjustable loans at their resets, and savings accounts whose banks choose to pass it on.
A quarter point on a $6,000 card balance is $1.25 a month
Interest on a revolving balance is the balance times the rate divided by 12. At 22% a $6,000 balance costs $110.00 a month; at 22.25% it costs $111.25. A $40,000 HELOC drawn interest-only goes up $8.33 a month on the same move.
Δ monthly interest = balance × Δrate ÷ 12
Small monthly amounts add up over a balance carried for years, and a series of moves compounds them. The quickest way to cut the effect is to shrink the balance that carries the highest rate.
An adjustable loan feels it most: $48.08 a month on $300,000
An adjustable-rate loan is re-amortized at each reset. On a $300,000 balance with 300 months left, the level payment at 7% is $2,120.34; at 7.25% it is $2,168.42, $48.08 more every month until the next reset.
Unlike a card, where only the interest changes, the whole payment moves, because the new rate applies to every remaining month. That is why the same quarter point costs a mortgage borrower dozens of dollars and a card holder a dollar or two.
$300,000, 300 months
payment at 7.00% = $2,120.34
payment at 7.25% = $2,168.42
change = +$48.08 a month
Savings rates follow at the bank’s pace
A bank decides how much of a rate change to pass to savers and when. At full pass-through a quarter point on $20,000 earns $4.17 more a month; many accounts move less, or later, which is what the pass-through setting is for.
Netting savings against debts shows the household view. In the example the debts cost $57.66 more a month and the savings earn $4.17 more, a net $53.50 a month, or $642 over a year.
Fixed-rate mortgages and loans do not move
A fixed-rate mortgage, auto loan or student loan keeps its rate for the life of the loan, whatever the Fed does. A rate change affects only new borrowing on those products and the variable-rate balances above.
That is why the calculator asks only for variable-rate lines. If you are shopping for a new fixed loan, the Fed’s range is one input among several; lenders price fixed loans off longer-term market rates.
Worked example
The September 16, 2026 increase of 0.25 points on one household.
Worked example
$6,000 card at 22% = +$1.25 a month
$40,000 HELOC at 8.5% = +$8.33
$300,000 adjustable loan, 300 months = +$48.08
$20,000 savings at 4% = +$4.17 earned
Net = +$53.50 a month
Limitations
Card issuers, HELOC lenders and banks set their own timing and margins; the calculator assumes the full move passes through unless you change it.
Fixed-rate loans are not affected and are not included.
Frequently Asked Questions
Did the Fed raise rates in September 2026?
Yes. On September 16, 2026 the Federal Open Market Committee raised the target range for the federal funds rate by a quarter point to 3.75%–4.00%, effective September 17.
How much will my credit card interest go up?
By about the balance times the increase divided by 12: on a $6,000 balance a quarter point adds $1.25 a month, once the issuer moves the card’s rate.
Does a Fed hike change my mortgage payment?
Not a fixed-rate mortgage. An adjustable-rate mortgage changes at its next reset; on $300,000 with 300 months left, 7% to 7.25% adds $48.08 a month.
Sources & References
Figures on this page are checked against primary, authoritative sources. Links open in a new tab.
Results are estimates based on the figures you enter and standard formulas. Rates, fees, taxes, and lender terms vary and change over time, so confirm important numbers with your lender or a qualified professional. This is educational information, not financial advice.
Published a Fed rate impact calculator starting from the September 16, 2026 increase to 3.75%–4.00% (Federal Reserve implementation note): card, HELOC, adjustable-rate loan and savings, with a pass-through setting.
Added an automated formula suite.
Show it to your clients, not just tell them
Mortgage brokers, accountants, and advisors embed this to walk clients through the numbers live — nothing they enter ever leaves their browser.