🗓️ Average Maturity Calculator

What does average maturity mean?

Average maturity summarizes multiple dated payments into a single representative number of days. It is amount-weighted: a larger payment has more influence on the result than a smaller payment. That is why average maturity is not the same as taking the simple average of the listed due dates.

This is useful in commercial finance, receivables planning, note scheduling, and payment negotiations. Instead of reading a long list of maturities, you get one day value that reflects both timing and amount.

How the formula works

The calculator multiplies each amount by its maturity in days, adds those weighted day values, and divides the total by the total amount. This gives an amount-weighted average maturity.

1. For each row, calculate amount × days.
2. Add all amount × days values.
3. Add all amounts.
4. Average maturity = total amount × days divided by total amount.
5. Approximate months are shown by dividing the day result by 30.

Day-count mode versus due-date mode

Use day-count mode when the number of days is already known for each payment. This is the quickest workflow for planned notes, invoices, or receivables where the maturity day count is already written in the table.

Use due-date mode when you know the actual due dates. By default no shared start date is required: each row's amount and due date are combined by amount weight into one average maturity date, shown as a plain calendar day. You can also turn on a shared start date to get the amount-weighted result in days instead, measured from that one reference date. Neither variant applies business-day calendars or holiday adjustments.

• Day-count mode is best when all day counts are already measured consistently.
• Due-date mode reduces manual counting errors when the dates are available, and needs no shared start date by default.
• With the shared-start-date option turned on, a due date before the start date is invalid because it would create a negative maturity.
• All variants use the same amount-weighted formula once each row's day count or date is known.

Worked example: 10,000 at 30 days and 20,000 at 60 days

Suppose one payment is 10,000 due in 30 days and another is 20,000 due in 60 days. Because the larger payment is due later, the weighted average maturity is higher than the simple average of 30 and 60.

1. First row: 10,000 × 30 = 300,000 amount-days.
2. Second row: 20,000 × 60 = 1,200,000 amount-days.
3. Total amount-days: 1,500,000.
4. Total amount: 30,000.
5. Average maturity: 1,500,000 / 30,000 = 50 days.

A simple average of the two day counts would be 45 days, but that ignores the fact that the 60-day payment is twice as large. The amount-weighted result is therefore 50 days.

When this calculator is the right tool

This page is the right tool for searches such as average maturity calculator, weighted average maturity, average due date, or maturity days for multiple payments. The input is a row list; the output is one weighted day result plus a row breakdown.

• Use it for multiple receivables, payment rows, bills, or notes.
• Use a discount calculator when you need the present cash value of a single nominal amount.
• Use an interest calculator when you need interest amount or rate-based growth.
• Use purchasing-power or monetary-value tools when inflation equivalence is the question.

Common mistakes to avoid

• Averaging the day counts without weighting by amount.
• Mixing day counts measured from different start dates.
• Reading average maturity as an interest or discount result.
• Expecting business-day or holiday-aware date counting.
• Entering a row partially and assuming it will be ignored safely; each participating row must be complete.