What is a bid bond?
A bid bond — also called bid security, a tender guarantee, or an earnest money deposit (EMD) — is a guarantee you submit together with your bid. It protects the buyer if you win the tender and then refuse to sign the contract or withdraw your offer. Walk away, and the bond is forfeited; lose the tender or sign normally, and it is released.
Bonds come in two main forms. A cash deposit locks real capital in an escrow or bank account until the tender closes. A bank guarantee or surety bond achieves the same protection for a fee — typically 0.5%–3% of the bond amount — leaving your working capital free. Which is cheaper depends on what your capital earns elsewhere; the break-even line above does that comparison for you.
How bid security is calculated
The formula is deliberately simple:
The rate is always set by the tender document, not by law alone — but most markets cluster around well-known conventions, which the presets above encode. Always verify against the document you are actually bidding on.
Bid bond vs performance bond vs advance payment guarantee
These three instruments secure different risks, and bidders routinely confuse them:
| Instrument | Secures | Typical amount | Lifecycle |
|---|---|---|---|
| Bid security / bid bond | Your promise to sign the contract if selected | 1–10% of bid price, often capped | With the bid; released after award |
| Performance bond | Your execution of the signed contract | ~10% of contract price | From contract signature through the defects period |
| Advance payment guarantee | The owner’s down payment to you | 100% of the advance | Reduces as the advance is deducted from progress payments |
Bid security requirements by market
Reference values used by the presets. Treat them as starting points, not substitutes for the tender document.
| Market | Typical rate | Cap | Notes | Source |
|---|---|---|---|---|
| US public works | 5–10% of bid price | None | Surety bid bond; percentage set by the tender document, state by state. The federal Miller Act covers performance & payment bonds. | State “little Miller Acts” / tender documents |
| China (PRC) | Max 2% of estimated price | ¥800,000 for construction | Validity must match the bid validity period. | Bidding Law implementing regulations, Art. 26; Seven-Ministry Order No. 30 |
| World Bank / MDB | ~2% or a fixed sum | None | Amount and currency stated in the tender data; usually valid 28 days beyond bid validity. | Standard Procurement Document, bid security clause |
| India | 1–3% of estimated cost | None | EMD per the NIT; registered MSMEs are often exempt. | General Financial Rules / NIT |
| UK / EU public contracts | Often none; 1–5% when required | None | Authorities rely on qualification screening; parent company guarantees are common. Performance bonds (~10%) are the bigger lever. | Public Contracts Regulations 2015; Directive 2014/24/EU |
Why multi-package totals matter
Large tenders are routinely split into lots or packages — site preparation, main structure, MEP, landscaping — and each lot requires its own bid security. Bidders lose deals by budgeting for one bond and discovering four. The table above totals every package, applies the cap per lot, and shows the full capital at risk plus the guarantee fees before you commit.
Frequently asked questions
How is a bid bond calculated?
Multiply your bid price by the bond rate stated in the tender document (commonly 1–10%), then apply any contractual or statutory cap. For example, a $5,000,000 bid at 5% requires a $250,000 bond. The calculator applies the rate and cap for you, per package.
Is a bid bond the same as bid security?
Yes — same instrument, different names by market: bid security (World Bank documents), tender guarantee, EMD (India), cautionnement (Francophone Africa), bid bond (the US surety market). The mechanics are equivalent: money or a guarantee at risk if you fail to honor your bid.
What happens to my bid bond if I win?
It is released or replaced. Once you sign the contract and post the performance bond, the bid security is returned (cash) or expires (guarantee) on the terms stated in the tender document. If you refuse to sign, it is forfeited to the buyer.
What is the difference between a bid bond and a performance bond?
Timing and risk. A bid bond secures your promise to sign if selected and is released after award; a performance bond (typically ~10% of the contract price) secures your execution of the work and runs through the defects liability period. You will usually post both — sequentially, not simultaneously.
How much does a bid bond cost?
If you post cash, the cost is your locked capital — often the real price. A bank guarantee or surety bond typically costs 0.5%–3% of the bond amount, depending on your credit standing and the market. Use the break-even line in the calculator: it tells you the annual return at which a guarantee becomes cheaper than posting cash.
Why another calculator?
Most bid bond tools stop at “price × percentage”. Real tenders have caps, multiple lots, and a financing decision hiding inside every bond. BondKit does all three in one page, with the market conventions cited — and keeps your numbers in your browser, not on a server.