Worked example · EX:time-value-of-money-and-financial-mathematics/ordinary-versus-due-service-plan

Value the same service payments in arrears and in advance

Hold payment amount, count, spacing, and rate constant to isolate the value effect of beginning versus end timing.

Updated Aug 7, 2026 Review due Nov 7, 2026
Worked-example setupScope and assumptions
  • Both alternatives contain exactly four annual $6,000 payments and use the same supplied 5 percent annual periodic rate.
  • Only every payment date shifts one year earlier in the due alternative.
Period
Four equal annual payment intervals
Units
USD at the month-zero valuation date and decimal rate per year
Rounding
Retain full precision; display currency to cents.

The ordinary alternative pays at years 1 through 4. The due alternative pays at years 0 through 3. Neither has five payments.

ordinary PV = $6,000 × [1 - (1.05)^(-4)] / 0.05
            = $21,275.7030…

due PV      = ordinary PV × 1.05
            = $22,339.4882…

At the same positive rate, the due stream has the higher value because every payment occurs one period earlier. The $1,063.79 displayed difference is a timing effect under the model, not evidence that either contract has better service, lower risk, or preferable legal terms.

Verified calculation · time value analysis

The curriculum loader recomputed this example before it entered the site build. Expand any structured input to inspect the stated facts.

annuities
2 fields
Inspect data
{
  "due_service": {
    "payment": 6000,
    "periodic_rate": 0.05,
    "periods": 4,
    "timing": "due"
  },
  "ordinary_service": {
    "payment": 6000,
    "periodic_rate": 0.05,
    "periods": 4,
    "timing": "ordinary"
  }
}

Recomputed result

Values recomputed by the curriculum loader
MeasureValue
due service future value27,153.7875
due service present value22,339.4882
ordinary service future value25,860.75
ordinary service present value21,275.703