Interest Swap Valuation Calculator

Analyze fixed and floating legs with payment schedules. Test discount rates, forwards, and positions easily. See valuation outputs, cash flows, and charts instantly today.

Calculator Inputs

Enter one line per payment in this format: payment_time_years, accrual_fraction, zero_rate_percent, forward_rate_percent

Example Data Table

Payment Time (yrs) Accrual Fraction Zero Rate % Forward Rate %
0.250.254.204.35
0.500.254.254.40
0.750.254.304.45
1.000.254.354.50
1.250.254.404.55
1.500.254.454.60

This sample represents a six-period plain-vanilla swap schedule with quarterly accruals, zero rates for discounting, and forward rates for expected floating coupons.

Formula Used

Fixed cash flow per period = Notional × Fixed Rate × Accrual Fraction

Floating cash flow per period = Notional × Forward Rate × Accrual Fraction

Discount factor depends on the selected compounding method and zero rate for each payment time.

Fixed leg present value = Sum of all fixed cash flows × corresponding discount factors

Floating leg present value = Sum of all floating cash flows × corresponding discount factors

Net swap value = Receive leg PV − Pay leg PV

Par swap rate = Floating Leg PV ÷ (Notional × Sum of Accrual Fraction × Discount Factor)

PVBP is estimated as Notional × Sum of Accrual Fraction × Discount Factor × 0.0001. It helps show approximate value change for a one-basis-point coupon move.

How to Use This Calculator

  1. Enter the swap notional and the fixed coupon rate.
  2. Select whether you pay fixed or receive fixed.
  3. Choose the compounding method for discount factors.
  4. Apply any parallel curve shock if you want a quick scenario test.
  5. Set the display currency and decimal precision.
  6. Paste the schedule as one row per payment date.
  7. Click Value Swap to show present values above the form.
  8. Use the CSV and PDF buttons to save the valuation output.

FAQs

1. What does this calculator value?

It values a plain-vanilla interest rate swap by discounting projected fixed and floating coupon cash flows. It then reports each leg’s present value, net value, par swap rate, and sensitivity summary.

2. Why are discount factors important?

Discount factors convert future payments into today’s value. A payment due later is worth less than one due sooner, so valuation must use payment timing and market discount rates together.

3. What is a payer-fixed swap?

A payer-fixed position pays the fixed coupon stream and receives floating payments. Its value rises when projected floating cash flows become more valuable than the fixed leg on a discounted basis.

4. Can I stress the curve?

Yes. Enter a parallel shock in basis points. The calculator shifts both zero and forward rates by that amount, allowing a quick scenario view of valuation changes under higher or lower rates.

5. Why can the par rate differ from my fixed rate?

The par rate is the coupon that would make the swap’s net value close to zero under the supplied curve. If your fixed coupon differs, the swap will usually show a gain or loss.

6. Does this model principal exchanges?

No. This page is designed for standard coupon-only plain-vanilla interest rate swaps. It does not include amortizing notionals, principal exchanges, stubs, convexity adjustments, or cross-currency features.

7. What schedule format should I enter?

Use one row per payment. Each row should contain payment time in years, accrual fraction, zero rate percent, and forward rate percent, separated by commas.

8. How should I read a negative net value?

A negative result means the swap is a liability for the selected position under the entered assumptions. The pay leg’s discounted value exceeds the receive leg’s discounted value.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.