Section 128 explained: this guide covers what it means, who it applies to, the step-by-step process, documents required, fees, due dates and penalties in India — so you can stay compliant with confidence and avoid costly mistakes.
Section 128 says how far a surety is liable: his liability is co-extensive with that of the principal debtor, unless the contract provides otherwise. It is the reason a surety can be called on for interest and charges as well as the principal sum. If you are a creditor sending a demand to a surety, or a surety who has received one, a legal notice needs to say clearly what is claimed and on what basis.
The liability of the surety is co-extensive with that of the principal debtor, unless it is otherwise provided by the contract. The Act's illustration: A guarantees payment of a bill of exchange by C, the acceptor. C dishonours the bill. A is liable not only for the amount of the bill, but also for any interest and charges which may have become due on it. The parties can narrow the surety's liability by the contract.
The text
"The liability of the surety is co-extensive with that of the principal debtor, unless it is otherwise provided by the contract."
"Co-extensive"
"Co-extensive" means of the same extent. The surety's liability matches the principal debtor's liability: where the principal debtor is liable for a sum, the surety is liable for the same sum, to the extent the guarantee covers it. Roles are defined in section 126; see section 126.
The section does not say that the surety and the principal debtor must be sued together, that the creditor must first proceed against the principal debtor, or in what order they are to be pursued. It states only the extent of liability. This article does not go beyond the text.
"Unless it is otherwise provided by the contract"
This is the built-in room for agreement. The contract can provide that the surety's liability is less than the principal debtor's: for example, limited to a fixed amount, to principal only, or to a stated period. Where the contract is silent, the liability is co-extensive.
The Act's illustration
A guarantees to B the payment of a bill of exchange by C, the acceptor. The bill is dishonoured by C. A is liable, not only for the amount of the bill, but also for any interest and charges which may have become due on it.
What the illustration shows: if the principal debtor (C) would owe the amount, interest and charges, the surety (A) owes them too, because his liability is co-extensive.
What "co-extensive" does and does not tell you
| Question | What the text says |
|---|---|
| Is the surety liable for the same amount as the principal debtor? | Yes, unless the contract provides otherwise. |
| Does the surety owe interest and charges? | In the Act's illustration, yes: interest and charges that became due on the bill. |
| Can the contract limit the surety's liability? | Yes: "unless it is otherwise provided by the contract". |
| Must the creditor sue the principal debtor first? | The section does not say. |
| What if the principal debtor has a defence? | The section does not deal with that; it states the extent of liability only. |
A modern example (ours)
Lakeview Builders borrows Rs. 50 lakh from Mercury Bank, with interest at an agreed rate and a clause for recovery charges on default. Nandini signs a guarantee of the loan. The builder defaults. Because Nandini's liability is co-extensive with the builder's, she is liable for the principal, interest and charges that are due from the builder under the loan, unless her guarantee provides otherwise. If her guarantee said, "my liability is limited to Rs. 20 lakh", that is a provision in the contract that makes her liability narrower than the principal debtor's.
What can the parties change?
This is the section's central feature: the contract may provide otherwise. Common ways include a cap on the amount, exclusion of interest or costs, a time limit on claims, or a limit to certain obligations of the principal debtor. If you are the surety, a limit should be written into the guarantee in clear words. If you are the creditor, make sure the guarantee says that the surety is liable for interest, costs and charges. Our overview of indemnity and guarantee: sections 124 to 147 lists the later sections that deal with the surety's rights and discharge.
Practical points
- Sureties: read the principal contract. Your liability follows it unless your own contract narrows it.
- Sureties: ask for a cap in writing if you want a ceiling on liability.
- Creditors: spell out interest, costs and charges in the guarantee so that there is no argument on extent.
- Demand notices should state the principal, interest and charges and how each was computed.
- Variation of the principal contract can affect the surety; the Act deals with it in section 133, covered in a later article: see section 133.
- For what the surety may do after paying, see section 140.
Need help with a demand to a surety?
A demand on a surety should show what the principal debtor owes, what the guarantee covers, and how the sums are made up. Our legal notice drafting service can prepare a clear demand, or help a surety respond to one. Bring the loan or supply contract, the guarantee and a statement of account.
Key takeaways
- The surety's liability is co-extensive with that of the principal debtor, unless the contract provides otherwise (s.128).
- In the Act's illustration, the surety on a dishonoured bill is liable for the amount plus interest and charges.
- The contract may narrow the surety's liability.
- The section does not say whether the creditor must first proceed against the principal debtor.
Read next
- Section 127: consideration for guarantee
- Section 129: continuing guarantee
- Indemnity and guarantee: overview of Sections 124 to 147
Disclaimer: Based on the text of the Indian Contract Act, 1872 as consulted on 1 October 2026. Many questions under this Act turn on case law and on the wording of the particular contract, which this article does not cover. It is general information, not legal advice; check the official text and take advice before acting.