Calcs.finance

investment calculator

Finance Calculator

The Finance Calculator is a five-key time-value-of-money solver. It takes N, annual I/Y, PV, PMT, FV, payments per year, compounding periods per year, and beginning or end payment timing, then solves the selected unknown and reports the solved value, future value, payment, annual rate, period count, present value, sum of payments, and total interest.

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Solve for
PMT made at

Result

Solved value
FV = $-9,455.36
Future value
-$9,455.36
Periodic payment
-$2,000.00
Interest rate per year
6.00%
Number of periods
10
Present value
$20,000.00
Sum of all periodic payments
-$20,000.00
Total interest
$9,455.36

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Before you calculate

Use this calculator when you need one generic TVM variable from the others and the cash-flow signs, period count, payment frequency, compounding frequency, and payment timing are explicit. Use Present Value or Future Value for narrower discounting or accumulation questions, Payment, Loan Payment, Interest Rate, APR, or Amortization for borrowing workflows, and official CFPB, Regulation Z, lender, Investor.gov, SEC, FINRA, IRS, FCA, MoneyHelper, product, adviser, legal, or local regulator sources for APR, lending disclosure, annuity, retirement-income, tax, investment-product, legal, product-specific, or jurisdiction-specific questions.

Formula summary

The app converts annual I/Y into a per-payment rate with r = (1 + interestRate / 100 / compoundPeriodsPerYear)^(compoundPeriodsPerYear / paymentPeriodsPerYear) - 1. The timing factor is 1 for end-of-period PMT and 1 + r for beginning-of-period PMT. Future value uses FV = -(PV * (1 + r)^N + PMT * (((1 + r)^N - 1) / r) * timingFactor), with FV = -(PV + PMT * N) when r is 0. Periodic payment and present value are rearrangements of the same equation. Interest-rate solve uses bisection over annual rates from -99.999% to 1000%, period-count solve uses bisection from 0 to 12000 periods, sumPeriodicPayments equals PMT * N, and totalInterest is abs(FV + PV + sumPeriodicPayments).

Worked example

Example: five TVM solve modes from fixture-backed inputs

Default FV solve: N = 10, I/Y = 6%, PV = $20,000, PMT = -$2,000, P/Y = 1, C/Y = 1, and end-of-period payments produce FV = $-9,455.36, sum of periodic payments of $-20,000.00, and total interest of $9,455.36. PMT solve with the same N, I/Y, PV, P/Y, C/Y, timing, and FV = $0 returns PMT = $-2,717.36, sum of payments of $-27,173.59, and total interest of $7,173.59. PV solve with N = 2, I/Y = 10%, PMT = $0, and FV = $-121 returns PV = $100.00 and total interest of $21.00. Changing the default FV example to beginning-period PMT changes the timing factor to 1.06 and returns FV = $-7,873.67. Using PMT = $-2,717.36 and FV = $0 over 10 periods returns I/Y = 6.00%, while solving N with that payment and rate returns 10 periods.

The examples show the TVM equation, signs, payment timing, and solver branches. They are not APR disclosures, lender quotes, annuity illustrations, retirement-income promises, tax calculations, investment recommendations, product comparisons, legal answers, or personal finance advice.

Assumptions

Common mistakes to avoid

Methodology and sources

This calculator is an original implementation based on documented formulas, app-specific assumptions, deterministic fixtures, edge cases, rounding policy tests, and internal validation. It is not copied from a single source.

Outputs are checked with deterministic fixtures, edge cases, rounding policy tests, and internal independent comparator checks where overlapping outputs are available. The result remains an educational estimate, not a quote, approval, tax answer, or personalised advice.

Formula version 2026.05.21-generic-tvm-five-key. The version marks the calculation logic and validation fixture set used for this estimate.

Estimate only

The result is educational and is not financial, tax, legal, lending, investment, or regulated advice. Real provider terms, fees, rates, taxes, and personal circumstances can change the final answer.

Formula and help: read the full finance calculator methodology notes.

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