A change follows the business facts, not a preferred exchange result
Under Ind AS 21, paragraphs 13 and 35–37, an entity changes functional currency only when the underlying transactions, events and conditions change. The resulting accounting is prospective from that date. Translate all items into the new functional currency at the exchange rate on the change date; the translated amounts of non-monetary items become their historical amounts. This is different from simply choosing a new presentation currency or changing the currency configured in an accounting system.
Build a dated economic assessment
Ind AS 21 in ICAI’s current compendium defines functional currency by the primary economic environment in which the entity operates. Paragraph 9 gives primary attention to the currencies influencing selling prices and the labour, material and other costs of supplies. Financing and retained operating receipts provide supporting evidence; foreign operations have additional indicators under paragraph 11. Where indicators conflict, paragraph 12 gives priority to the primary indicators and requires management judgement. A single foreign loan, parent instruction or temporary exchange-rate movement is not a numerical safe harbour for changing the conclusion.
Document what changed, when it became effective and why it changes the primary economic environment. Relevant records can include revised sales contracts, sustained pricing and sourcing changes, cost commitments and the timing of an operating-model transition. No statutory majority-of-revenue percentage is invented here. The date must follow the evidence; it is not automatically the first day of the financial year or the date a software migration finishes.
Separate the translation at change from later exchange accounting
First prepare a reliable carrying-amount trial balance in the old functional currency at the change date, including the adjustments required up to that point. Translate that complete balance into the new functional currency at that date’s rate. Preserve the mapping and reconcile the resulting ledger. This accounting translation does not amend the company’s legally denominated share capital, contracts, tax filings or registry records. Those require their own applicable-law analysis.
After the change, apply the normal monetary and non-monetary rules using the new functional currency. A fixed rupee payable can become a foreign-currency monetary item when USD becomes functional; a USD receivable can cease to be foreign currency for that entity. A non-monetary historical-cost item does not keep being reset merely because the INR/USD closing rate subsequently changes. Fair-value measurements, impairment, hyperinflation, lack of exchangeability and hedge accounting can require additional analysis. The examples assume exchangeable currencies, ordinary non-hedged monetary balances and no such complications.
Do not clear the translation reserve through earnings
Paragraph 37 expressly preserves previously recognised foreign-operation translation differences in other comprehensive income until the relevant disposal requirements apply. A functional-currency change alone does not justify recycling them to profit or loss. Paragraph 54 requires disclosure of the fact, reason and date of a change in the reporting entity’s functional currency or that of a significant foreign operation. If presentation currency differs from functional currency, paragraph 53 separately requires that fact, disclosure of the functional currency and the reason for using the different presentation currency. Keep the change-date ledger conversion distinct from the subsequent presentation-currency translation of financial statements.
Mistakes that the working should expose
Watch for retrospective rewriting of all past transactions as though the new functional currency had always applied, rates quoted in the wrong direction, conversion of assets without liabilities, arbitrary retained-earnings balancing gains, and a change justified only by management preference. A genuine prospective change is different from correcting a previously erroneous functional-currency conclusion. The latter needs the applicable error-correction analysis rather than a change label used to avoid it.
Six worked illustrations
All facts and amounts below are fictional. Assumptions describe the model, not additional statutory rules.
Illustrative example 1: Historical-cost item at the change date
Assume a supported INR-to-USD functional-currency change on 1 October 2026 at ₹80 per USD. An inventory item’s valid INR carrying amount is ₹80,00,000. Its translated historical amount is USD 1,00,000. A later ₹82 rate does not by itself reduce that non-monetary historical amount to USD 97,560.98.
Illustrative example 2: Convert a balanced ledger
On the same assumptions, a simplified opening ledger has assets ₹1,80,00,000, liabilities ₹60,00,000 and equity ₹1,20,00,000. Translation at ₹80 gives USD 2,25,000, USD 75,000 and USD 1,50,000 respectively. Assets still equal liabilities plus equity. This is an accounting balance reconciliation, not a legal redenomination of issued shares.
Illustrative example 3: Rupee liability after USD becomes functional
An ₹8,00,000 ordinary monetary payable translates to USD 10,000 at the change-date rate of ₹80. At a later closing rate of ₹82 it is USD 9,756.10. The isolated exchange gain is USD 243.90, rounded to cents, assuming no intervening payment, hedge or other special treatment.
Illustrative example 4: USD receivable after the change
A USD 10,000 receivable has already been correctly carried at ₹8,60,000 immediately before a supported change when the rate is ₹86. It translates to USD 10,000. Collection of USD 10,000 after the change, when the rate is ₹88, produces USD zero settlement exchange difference in the new functional currency. A separate INR presentation working may still move.
Illustrative example 5: New foreign-currency transaction
After USD becomes functional, an ordinary ₹4,20,000 service payable is initially recognised when the spot rate is ₹84 per USD: USD 5,000. It is settled when the rate is ₹87.50, requiring USD 4,800. The isolated settlement exchange gain is USD 200, assuming the stated normal treatment and no other changes.
Illustrative example 6: Existing translation reserve
Assume an existing, validly accumulated foreign-operation translation reserve of USD 30,000 is already identified in the relevant group equity schedule. A functional-currency change alone permits USD zero recycling to profit or loss. With no other reserve movements in this simplified illustration, USD 30,000 remains accumulated; any later disposal must be analysed separately.
Ten-step verification table
| Step | Action | Evidence |
|---|---|---|
| 1 | Confirm Ind AS applicability | Identify the reporting entity and existing functional currency. |
| 2 | Collect primary indicators | Retain pricing and labour/material/other cost evidence under paragraph 9. |
| 3 | Assess supporting indicators | Document financing, retained receipts and foreign-operation factors where relevant. |
| 4 | Identify the underlying change | Distinguish sustained economic changes from a preferred reporting result. |
| 5 | Support the effective date | Link the date to contracts and operating evidence. |
| 6 | Close the old-currency ledger | Complete relevant adjustments before the change-date conversion. |
| 7 | Verify rate direction | Retain the dated spot-rate source and INR-per-USD convention. |
| 8 | Translate and reconcile all items | Tie assets, liabilities and equity without an invented balancing profit. |
| 9 | Preserve subsequent measurement | Track monetary exposure and new historical amounts separately. |
| 10 | Complete disclosures and reserve review | State reason/date and prevent unsupported OCI recycling. |
Sixteen practitioner FAQs
1. Can management choose any functional currency?
No. It follows the primary economic environment and the standard’s indicators.
2. Is a parent’s reporting currency automatically the subsidiary’s functional currency?
No. Assess the subsidiary’s own facts, including the additional foreign-operation indicators.
3. Does a new foreign loan alone settle the issue?
Financing is supporting evidence. Apply the priority given to the primary indicators rather than treating one loan as decisive.
4. Is a revenue percentage prescribed as a universal trigger?
No such universal numerical threshold is specified in the cited paragraphs.
5. When is the change accounted for?
Prospectively from the date the underlying change supports the new functional currency.
6. Must that date be 1 April?
No. The date follows the relevant economic facts, which can change during a reporting period.
7. What rate translates the change-date balances?
The exchange rate at the date of change, applied to all items under paragraph 37.
8. Does a historical inventory amount keep its old INR number as its USD cost?
No. Its new functional-currency historical amount is the translated change-date amount.
9. Can a rupee payable become foreign currency after the change?
Yes. If USD becomes functional, a fixed INR monetary liability needs subsequent foreign-currency analysis.
10. Does a USD receivable still create USD exchange differences when USD is functional?
The same fixed USD amount is no longer foreign currency to that entity; distinguish separate presentation-currency effects.
11. Does this change legally redenominate share capital?
No. Accounting translation does not itself amend legally denominated shares or contracts.
12. Should every historical transaction be reconstructed in the new functional currency?
A genuine change is prospective. Do not treat it as though the new functional currency had always applied.
13. Is presentation-currency selection the same decision?
No. Paragraphs 38 onwards govern use of a presentation currency different from functional currency.
14. Can the translation reserve be released merely because functional currency changes?
No. Paragraph 37 preserves the relevant accumulated differences until the disposal requirements apply.
15. What does paragraph 54 require?
Disclose the change, its reason and its date for the reporting entity or a significant foreign operation.
16. What if the original functional-currency determination was wrong?
Assess error correction under the applicable standard. Calling it a prospective change does not resolve a prior error.
Conclusion
A functional-currency change needs changed underlying economic facts. Translate all items at the change-date rate, preserve new historical amounts and disclose the reason and date.