What This EIDL Calculator Actually Models
The tool runs two phases that mirror how SBA serviced these notes. Phase one compounds your loan amount at the monthly note rate for every deferment month, because unpaid interest was capitalized rather than waived. Phase two re-amortizes that grown balance across the months remaining in the term, which is what your servicer did when the payment finally started. On the default $150,000 note at 3.75%, the balance hits $161,663.72 after 24 deferred months and the payment lands at $777.84.
The re-amortization step is where most hand math goes wrong. Original estimates divided the note over 360 payments from month one, which produces $694.67 on the default example. Deferral consumed 24 of those months without a single payment, so the grown balance amortizes over 336 months instead. Fewer months on a bigger balance pushes the payment $83.17 higher, and that gap persists for the life of the loan. An amortization calculator shows the same mechanics on any fixed loan.
Under the hood, the schedule is simulated month by month with cent-level rounding, the same approach servicer systems use, and it stops with an honest warning if a payment can never clear the balance. Borrowers who want the sibling problem — how interest accrues on deferred student-style debt before repayment begins — can model it with the deferred payment loan calculator. Both tools capitalize deferred interest, which is the detail most estimates skip.
The Real Cost of Deferment, in Dollars
Deferment was payment relief, never interest relief. At 3.75%, the monthly rate is 0.3125%, so the first deferred month accrues $468.75 per $150,000 borrowed and the figure grows as the balance compounds. Twelve deferred months add $5,722.69 and lift the payment to $734.69. Twenty-four months add $11,663.72 and lift it to $777.84. Thirty-six months add $17,831.40 and push the payment to $824.49 — a $129.82 monthly gap versus the original estimate.
Nonprofit notes accrued more slowly at 2.75%. The same $150,000 with 24 deferred months grows by $8,471.12 instead of $11,663.72, and the payment lands at $676.81. If your portal shows a balance larger than what you originally signed for, capitalized deferment interest is nearly always the reason. The line items rarely appear separately, which is exactly why this tool itemizes the growth before your eyes.
Borrowers whose deferment already ended should work from the current balance, not the original note amount. Enter the capitalized balance from the servicer portal as the loan amount and set deferment months to zero — the growth already happened, and what remains is a plain fixed-rate loan you can prepay or refinance on its own merits.
What 3.75% Fixed Costs Over 30 Years
The default example pays $262,132.08 against $150,000 borrowed — $112,132.08 of interest, or 74.8% of principal stacked on top. Without the 24-month deferment the same note costs $100,775.87 in interest, so deferral carried an $11,356.21 premium. That is the price of the cash-flow relief, and seeing it as a single number beats guessing at it for years.
The scale is linear, which helps for quick mental checks. A $50,000 note with the same terms runs $259.28 per month and $37,377.36 of total interest, while a $500,000 note runs $2,592.80 per month and $373,773.60 of interest. A $25,000 note — a common smaller EIDL size — pays $129.64 per month and $18,688.68 of interest across the full term.
That fixed 3.75% also turned out to be an accidental hedge. Small-business rates climbed well above it after 2022, so the loan became the cheapest line on many balance sheets. The same deferment-then-repayment structure appears in federal education debt, and the student loan calculator models that variant for borrowers juggling both.
Prepayment Math: Killing 30 Years of Interest
EIDL notes carry no prepayment penalty, and extra dollars apply straight to principal. Adding $100 per month to the default example saves $20,726 in interest and clears the note 62 payments sooner. Two hundred extra saves $33,318 and cuts 103 payments. Five hundred extra saves $55,122 and ends the loan 175 payments early — nearly 15 years of scheduled payments erased.
Timing matters as much as amount. Extra principal in the first years after deferment removes debt that would otherwise sit through decades of compounding, while the same dollars in year twenty save far less. A practical escalation works well here: round the payment up to a flat figure now, then raise it by $25 whenever revenue ticks up, and let the schedule quietly collapse.
For a single-debt schedule view, the loan payoff calculator breaks down principal versus interest by month, which pairs well with the totals reported here. Borrowers balancing several business debts at once should sequence by rate, a decision covered in the next section.
Where the EIDL Sits in Your Debt Stack
A fixed 3.75% belongs at the back of the payoff line. Ten thousand dollars of credit card debt at 25% APR burns about $2,500 a year, while the same balance on an EIDL costs $375. Attack the expensive money first and send the EIDL its minimum until cards, merchant advances, and equipment loans clear.
For budgeting, the default payment equals $9,334.08 per year. Against $300,000 of annual revenue that is 3.1% of sales; against $120,000 it is 7.8%. Tracking the payment against actual inflows is easier with a cash flow calculator, and the honest ratio tells you whether prepayment or reserves deserve the next spare dollar.
The note also affects borrowing capacity. When you apply for new financing, lenders test whether operating income covers existing debt service, and the EIDL payment counts in that math. The DSCR calculator computes the coverage ratio from your numbers, and the business loan calculator prices what a new loan would add on top.
Refinancing and Consolidation Decisions
A refinance wins only when the new rate is meaningfully lower after fees and the term does not secretly stretch the debt. Work the break-even first: a $2,500 closing cost recovered by $60 of monthly savings takes 42 months to pay back, and deals that recoup in under two years are rare against a 3.75% base. If the new note adds a balloon or resets to a variable rate, the comparison gets worse.
Watch what collateral and guarantees attach to the new loan. The original EIDL required no collateral for most balances and carried broad deferment rights in disaster scenarios. Swapping that flexibility for a bank facility that demands a personal guarantee or a lien on equipment is a real cost that never appears in the rate quote.
Consolidation deserves the same skepticism. Rolling a 3.75% note into a facility priced off current small-business rates usually raises the blended cost even when the single monthly payment looks smaller. Judge every offer by total remaining interest over a matched horizon, including fees — the exact figure this tool reports for keeping the loan.
Budgeting a Payment That Outlives Most Plans
A 30-year note spans recessions, price cycles, and at least one building lease, so the payment needs a permanent line in the budget rather than a mental note. At the default figures, that is $777.84 every month or $9,334.08 a year. Building the annual view with a business budget calculator keeps the line visible when revenue shifts and other costs fight for the same cash.
Seasonal businesses should hold one full payment in reserve during strong months, because servicers rarely align due dates with slow seasons. Auto-pay avoids late marks on a loan that will report into your business credit file for decades, and a small buffer absorbs the months when receivables run late.
Escalation beats willpower for the long haul. Raising the extra payment by $25 a year compounds quietly: the first bump is barely felt, and by year ten the note is tracking years ahead of schedule. The calculator shows the end state instantly, which is the motivation a three-decade commitment otherwise lacks.
Reserves Before the Next Disaster Hits
The 2020 experience taught the timing lesson: EIDL funding took weeks to months to arrive while rent and payroll kept running, and businesses with cash bridged the gap while others closed. A reserve of three to six months of expenses changes that outcome. Sizing the target starts with an emergency fund calculator applied to your business, not your household.
The engine underneath that target is your monthly consumption of cash. The burn rate calculator converts expenses into a monthly burn figure, and burn times your chosen coverage months equals the reserve you need. A business burning $12,000 a month that wants four months of cover needs $48,000 parked somewhere boring and liquid.
Debt is the expensive substitute for reserves — disaster loans arrive late, accrue from day one, and take decades to clear. Pairing a real reserve with insurance that matches your actual risks costs money every year, but it is the version of disaster protection that never capitalizes at 3.75% and never sends a monthly statement.