How to use this calculator
- Pick what to solve for. Choose Annual rate, Monthly payment, Present value, Number of payments, or Future value from the "Solve for" dropdown.
- Fill the other four fields. Enter the known values. Use a negative number for money you pay out (e.g., a purchase price) and a positive number for money you receive.
- Read the result and amortization schedule. The solved value updates live as you type. The amortization schedule below the solver shows month-by-month principal and interest breakdown.
Try some example scenarios
Solve for: Annual rate (I/YR) Monthly payment (PMT) Present value (PV) Number of payments (N) Future value (FV)
Number of Payments (N) ⓘ
Annual Interest Rate (I/YR) ⓘ
%
Present Value (PV) ⓘ
$
Monthly Payment (PMT) ⓘ
$
Future Value (FV) ⓘ
$
Advanced (payments per year, begin/end mode)
Payments per year
Payment timing End of period (standard amortizing loan) Beginning of period (annuity due)
How this compares to other TVM calculators
| Feature | FIXnotes | 10bii | Bankrate | FCI |
|---|---|---|---|---|
| Solves all five TVM variables | ✓ | ✓ | Partial | Partial |
| Renders amortization schedule | ✓ | ✓ | ✓ | ✓ |
| Uses NET payment for partial yield (servicing fee deducted) | ✓ | ✓ (manual) | — | ✗ (uses gross) |
| Renders partial buyer's amortization (not the loan's) | ✓ | ✓ (manual) | — | ✗ |
| Begin / End mode toggle | ✓ | ✓ | ✗ | ✗ |
| Worked examples for note investors | ✓ | ✗ | ✗ | ✗ |
| Free to use, web-based | ✓ | App ($) | ✓ | ✓ (account required) |
Frequently Asked Questions
What is the time value of money?
The time value of money (TVM) is the principle that a dollar today is worth more than a dollar tomorrow because today's dollar can be invested and earn interest. Note investors use TVM math to compare a lump-sum purchase price against a future stream of monthly payments and determine the yield (IRR) on the investment.
How do note investors use TVM calculations?
Note investors use TVM solvers to answer questions like: "If I pay $X today for a $Y/month payment stream lasting N months, what is my annualized yield?" or "What price should I pay to hit a 12% yield on a 60-month payment stream of $400/month?" The math is the same regardless of which variable you're solving for.
What is the difference between PV and PMT?
PV ( Present Value) is a one-time amount today — typically the purchase price or current loan balance. PMT (Payment) is a recurring amount paid at regular intervals — typically monthly. TVM math relates the two through interest and time.
Why does the same payment stream show different yields when I add a servicing fee?
The servicing fee comes out of every payment before it reaches the investor. If the gross payment is $400/mo and the servicing fee is $20/mo, the investor actually receives $380/mo. Calculating yield on $380 instead of $400 produces a lower (and accurate) annualized return. The difference between using gross vs net payment is the most common error in third-party partial-sale calculators.
When should I use Begin mode vs End mode?
End mode is the default and applies to virtually all amortizing mortgage loans — payments are due at the end of each period. Begin mode applies to lease payments and some annuity-due contracts where the payment is due at the start of the period. If you're analyzing a note, use End mode.
How does this compare to a 10bii financial calculator?
This calculator solves the same equations as a 10bii or HP-12C and produces the same numbers. Two differences: (1) input labels are plain English instead of cryptic abbreviations like I/YR; (2) the amortization schedule renders automatically alongside the solved variable so you can verify the math row-by-row. For most note-investor workflows, this is faster than using a separate calculator app.
How this calculator computes results
Calculations solve the present-value annuity equation PV + PMT × annuityFactor(r, n) + FV × (1+r)−n = 0 for the unknown variable. Rate solves use Newton-Raphson iteration with a bisection fallback when the iterative method diverges; convergence is tested to 1e-7 against the residual.
For independent verification, the same inputs entered into a 10bii or HP-12C financial calculator will produce identical results.
Last updated: May 2026