You bill a US client $1,500. On invoice day the dollar is at one rate, three weeks later the money reaches your account at another, and the bank's credit advice shows a third number after its charges. Then you sit down to fill in GSTR-1 and wonder which rupee value belongs in the return. Many guides tell you to use the RBI reference rate, and that advice is out of date for services.
For services, Rule 34(2) of the CGST Rules says the rupee value of a foreign-currency supply is worked out at the rate of exchange determined under generally accepted accounting principles for the date of time of supply. The RBI reference rate was the original 2017 wording and was replaced weeks later. Here is how to choose a rate, which date counts, what an export invoice must show, and why GST, income tax and your bank can each give a different rupee figure.
Rule 34(2) points to accounting principles, not to a fixed RBI rate
The CGST Rules contain two rules for converting currency. Rule 34(1), for goods, uses the rate notified by the Board under the Customs Act. Rule 34(2), for services, reads that the rate of exchange for determining the value of taxable services is the applicable rate determined as per generally accepted accounting principles for the date of time of supply under Section 13. The consolidated rules on the CBIC site note that the original reference-rate wording was amended on 27 July 2017. That compilation carries a disclaimer that only gazette notifications have legal force, so check for later changes.
In practice, "accounting principles" means your own consistent policy. A common choice is the reference rate published for that date, but the rule does not require that rate. Pick one source, write it down, and apply it to every invoice.
The date that counts is the time of supply, which can be the payment date
Section 13 of the CGST Act sets the time of supply for services. In broad terms, if you issue the invoice within the time Section 31 allows, the time of supply is the earlier of the invoice date and the date payment is received. If you do not invoice in time, it is the earlier of the date you provided the service and the date payment is received. Payment received counts from the earlier of the date it is entered in your books or the date it is credited to your bank.
So an advance paid before you invoice can pull the rate date earlier for that amount. How that works for an export advance is a point to confirm with your CA before you rely on it. The guide on invoicing an advance payment explains the invoice side.
An export invoice carries an endorsement, and good practice shows the rate
Under Rule 46, an invoice for an export must carry a statement that the supply is meant for export, either on payment of integrated tax or under bond or Letter of Undertaking without payment of tax, and must show the recipient's name and address and the country of destination. Check the exact wording against the rules before you copy it. The rule does not require the exchange rate to be printed, but showing the foreign-currency amount, the rate, where you took it from and the rupee value is good practice, and it saves arguments later. The guide to GST invoices for freelancers lists the other fields.
Under a valid LUT, the GST charged is nil, as the guide on LUT and GST for freelance exports explains.
In GSTR-1, an export of services goes in Table 6A
On the GST portal's GSTR-1 guide, export invoices are reported in Table 6A with the invoice number and date, total invoice value, whether tax was paid, and the taxable value. The port code and shipping bill fields are mainly relevant to goods, so for services check how the portal treats them or ask your CA. The portal is a rupee return, so keep the rupee values consistent with your books.
Income tax uses a different rule, so do not reuse the GST rate
For income tax, Rule 115 of the Income-tax Rules converts foreign income at the SBI telegraphic transfer buying rate on a date the rule specifies, which differs by type of income. The date is not the same as the GST time of supply, and the rule has its own exceptions, so ask your CA which rate and date apply to your professional income. The Income-tax Act 2025 renumbers these rules from 1 April 2026.
The rupees that reach your account after bank charges are a third figure. They are your evidence of receipt, as the guide on FIRC versus FIRA explains, and they are not what you report as the GST value. Any gain or loss between the invoiced and received amounts is a matter for your books. Whether GSTR-1 changes when the rupees received differ is not clearly settled, so confirm it with your CA, and see the guide on currency risk for freelancers for managing the swing itself.
Record the rate on every export invoice
Whatever source you choose, record it on the invoice and in your books. Rinto creates GST-ready invoices with automatic IGST, CGST and SGST calculation, so your own records stay consistent. It does not file your returns or choose your exchange rate policy, which you set with your CA. The guide on invoicing international clients from India covers the rest of the process. This post is general information, not tax advice.
Frequently Asked Questions
Which exchange rate should I use on a GST export invoice?
For services, Rule 34(2) of the CGST Rules says to use the rate of exchange determined under generally accepted accounting principles for the date of time of supply. It does not require the RBI reference rate, though many businesses choose the published reference rate as their policy. Pick one source, write it down and apply it to every invoice. The customs-notified rate in Rule 34(1) is for goods, not services. Ask your CA to confirm your policy. Keep the source and date of the rate with each invoice.
Does GST law require the exchange rate to be printed on the invoice?
Rule 46 does not list the exchange rate or a rupee equivalent among the required fields. An export invoice must carry the export endorsement, either on payment of integrated tax or under bond or Letter of Undertaking, along with the recipient's name, address and country of destination. Showing the foreign-currency amount, the rate, its source and the rupee value is good practice, not a rule, and it helps if your return is ever questioned. Check the rule text before copying the endorsement. Keep a copy of your LUT acknowledgement with the invoices.
What is the time of supply for a service exported to a foreign client?
Section 13 of the CGST Act sets it. In broad terms, if you issue the invoice within the Section 31 time limit, it is the earlier of the invoice date and the payment date. If you do not, it is the earlier of the date you provided the service and the payment date. An advance can pull the date earlier for that amount, and how that applies to exports is worth confirming with your CA before you rely on it.
Is the GST exchange rate the same as the income tax rate?
No. GST follows Rule 34(2) of the CGST Rules, using a rate set under accounting principles on the date of time of supply. Income tax follows Rule 115, which uses the SBI telegraphic transfer buying rate on a date the rule specifies for each type of income. The rupees credited to your bank, after fees, are a third figure. Each serves a different purpose, so keep all three on file and ask your CA which dates apply to you. Each figure has its own purpose, so do not substitute one for another.
Where do export of services invoices go in GSTR-1?
In Table 6A, with the invoice number and date, the total invoice value, whether tax was paid, and the taxable value. The port code and shipping bill fields are mainly relevant to goods, so for services check how the portal treats them or ask your CA. The return is in rupees, and the figures should match your books. If you supply under a Letter of Undertaking, the tax charged is nil. Keep your LUT acknowledgement and invoices together in case of questions. Check the portal's current format before you file.