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Finance & Irish taxes · Calculator companion · By K Imports

Dated investment XIRR: practical guide

This guide explains how to use the Count.ie dated investment xirr. Measure annualised return from actual dated cash movements. Follow the inputs, method and worked example below, then compare your own scenario.

Guide written .

Open the Dated investment XIRR calculator

What to prepare

  • Have the figures for annual discount rate (%) ready, from a dated document, with the period (annual, monthly or per transaction) that each input expects.
  • Note the date of the transaction, since this model has no year selector and fixed rates may have changed.
  • Separate known facts from assumed rates before relying on the headline result.

Understand the inputs

The calculation method

Combine same-date flows and discount by elapsed actual days divided by 365.

Worked example

Illustrative inputs and their result.

Example inputs

Dated cash flows: YYYY-MM-DD, amount
2025-01-01, -10000 2025-06-01, 1000 2026-01-01, 10500
Annual discount rate (%)
5

Calculated example result

Annualised Xirr Percent
15.9039%
Dated Net Present Value
€980.02

How to interpret the result

Rows: YYYY-MM-DD, signed flow. Distinguish a tax saving, a tax bill, cash received and money remaining: they are not interchangeable. An estimate does not establish eligibility, filing compliance or when a refund will be paid.

Change one input of dated investment xirr at a time and record the result; keep a record of the year, date and assumptions so a change in the result can be explained.

Common mistakes to avoid

  • Do not mix tax years or apply a newly announced measure to an earlier transaction.
  • Avoid counting an allowance, credit, contribution or loss twice.
  • Check exclusions and personal circumstances before relying on the headline result.

Assumptions and sources

Rows: YYYY-MM-DD, signed flow. Single sign change required for a reported root; different conventions can change results.

If your case falls outside this scope, use a more suitable calculator or contact us about an unclear method.

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