Promo codes are used to influence purchasing decisions, test pricing strategies, and track how customers respond to different offers. Used strategically, promo codes can help drive conversions without changing core pricing or long-term value. Promo codes or other types of discount pricing are used in 38% of all online purchases.

Below, we’ll explain what a promo code is, how they work at checkout, and how businesses use them to shape demand and measure results.

What’s in this article?

• What is a promo code?
  
• How do promo codes work at checkout?
  
• Why do businesses use promo codes?
  
• What are the most common types of promo codes?
  
• What rules and restrictions apply to promo codes?
  
• How do businesses track promo code performance?
  
• How are promo codes different from coupons or discounts?
  
• How Stripe Checkout can help
  

What is a promo code?

A promo code is a short string of letters and/or numbers that a customer enters on a checkout screen to unlock a specific offer. That promotional offer might be a price reduction, free shipping, bonus item, or some other benefit tied to the purchase.

Promo codes can help businesses win new customers and better understand which channels and pricing strategies have the best results.

How do promo codes work at checkout?

The customer enters the promo code into a designated field during the checkout flow, typically labeled “promo code,” “discount code,” or something similar. The system checks whether the code is valid by confirming that it hasn’t expired, exceeded its usage limits, or already been used by that customer. The system then confirms that the order meets the code’s conditions, including minimum purchase amounts, eligible products or plans, customer type (e.g., new vs. returning), or geographic constraints.

If the code is valid, the checkout calculates the promotion based on its structure. That might mean applying a percentage off, subtracting a fixed amount, waiving shipping fees, or adding a bonus item. The adjusted total is shown immediately, with the discount clearly reflected before final payment.

If the code doesn’t qualify, the checkout flow typically returns a message explaining why. Common reasons include expired codes, unmet minimums, or ineligible items in the cart. Once the customer pays, the transaction is recorded with the promo code attached, allowing the business to track how and where the code was used.

Why do businesses use promo codes?

Promo codes allow businesses to influence buying behavior without changing their core pricing or product structure. Promo codes preserve the perceived value of a product instead of lowering list prices. Customers who receive the discount feel rewarded, while base pricing stays consistent for everyone else.

Here are common reasons why businesses use promo codes:

• Driving first-time purchases: A targeted introductory offer can turn curiosity into a first transaction without committing the business to a permanent discount.

• Increasing conversion: When customers hesitate at checkout, a promo code can be the nudge that closes the sale. This is especially effective for price-sensitive purchases.

• Encouraging repeat purchases: A code sent after a purchase, during a renewal window, or as part of a customer retention effort can bring customers back sooner and more often.

• Controlling when and how discounts apply: Promo codes can be limited to certain products, order sizes, customer segments, or time periods, which keeps pricing controlled.

• Supporting specific marketing campaigns: Promo codes pair naturally with email, social media, paid ads, partnerships, and affiliate programs. Unique codes make it easy to tie revenue back to a specific campaign or channel.

• Testing pricing and offers: Businesses can test different discount levels, structures, or eligibility rules and compare performance without committing to long-term changes.

• Clearing inventory or shaping demand: Promo codes help move excess stock, promote underperforming products, or shift demand toward higher-value bundles.

• Creating urgency without pressure: Time-bound or limited-use codes create a natural reason to act now. That urgency is often more effective and less disruptive than permanent price cuts.

What are the most common types of promo codes?

Promo codes tend to fit a few well-established patterns, shaped by how widely they’re shared and what kind of benefit they deliver.

Here are the most common promo codes based on deployment:

• Public promo codes: Broadly available and easy to find, often promoted on websites, ads, and social channels. They’re commonly used for seasonal sales, launches, or high-visibility campaigns where reach matters most.

• Private promo codes: Often delivered through email, direct outreach, or account-level messaging. They can reward loyalty, encourage repeat purchases, or support targeted offers.

• Single-use or unique codes: Useful for referrals, customer support adjustments, or highly controlled promotions where sharing isn’t intended.

• Restricted promo codes: Restricted by order value, product type, customer status, geography, or purchase channel.

Promo codes can also unlock different kinds of deals:

• Percentage-based discounts: Reduce the price by a set percentage, such as 10% or 20% off. They scale naturally with order size, which makes them effective for encouraging larger purchases.

• Fixed-amount discounts: Easy for customers to understand and work well when paired with minimum spend requirements, such as $5 off a purchase of $50 or more.

• Free shipping codes: Especially effective when shipping fees are a common source of cart abandonment. Businesses usually set a minimum spend threshold with these codes.

• Buy-more, get-more offers: Designed to increase average order value by encouraging customers to add more items to their purchase. For example, a 10% discount when they buy two of the same item.

• Bonus item codes: Add a bonus item to the purchase at a certain threshold as a way to reward customers without cutting into revenue.

What rules and restrictions apply to promo codes?

Rules are what turn promo codes from blunt discounts into precise tools.

Here are the code rules you should consider:

• Expiration windows: Time limits prevent outdated offers from lingering and create a clear incentive for customers to act while the code is still valid.

• Usage limits: A business might restrict a code to one use per customer, and/or limit the total redemptions to a certain number to prevent overuse.

• Minimum purchase requirements: Many promo codes only apply once an order reaches a certain value. This encourages customers to add more to their cart and helps offset the cost of the discount.

• Product eligibility: Some codes apply only to specific products, categories, or subscription tiers. This keeps discounts focused on the items a business wants to promote, rather than reducing prices across the board.

• Customer eligibility: Promo codes are often limited to certain customer groups, such as first-time buyers, returning customers, or specific accounts. Eligibility is typically determined by account status or purchase history.

• Geographic and channel constraints: A code might only work in certain countries, regions, or sales channels. These limits account for pricing differences, shipping costs, regulatory requirements, or channel-specific campaigns.

• One-code-per-order rules: Checkout systems typically allow only one promo code per transaction. This prevents stacking multiple discounts in ways that could erode margins or create unintended pricing outcomes.

• Single-use conditions: Some promo codes are generated for one-time use or for a specific customer. They can’t be reused or shared, which is useful for referrals and customer service adjustments.

How do businesses track promo code performance?

Promo codes are valuable partly because each redemption ties a specific transaction to a specific offer. This makes it easy to understand which strategies work and why.

These metrics can tell you about promo code performance:

• Redemption volume: How many times a promo code is used over its lifetime.

• Redemption rate: How many people received it vs. how many actually used it.

• Revenue attributed to the code: How much revenue the promotion generated.

• Average order value impact: Which promo codes increased average order value and which didn’t. Minimum spend requirements and bundle-based offers might have more of an impact than simple discounts.

• Customer-type analysis: How promo code usage split between new vs. returning customers. This helps businesses understand whether a promotion is driving acquisition, customer retention, or both.

• Channel and campaign attribution: Which efforts contributed most directly to conversions.

• Timing and urgency signals: When codes are redeemed relative to when they’re issued. Fast redemption can signal strong urgency, while slower usage can indicate a longer consideration cycle.

• Longer-term customer behavior: Repeat purchase and churn rates after a promo code is used. This helps determine whether a promotion attracted durable customers or one-time bargain seekers.

How are promo codes different from coupons or discounts?

These terms are often used interchangeably, but they point to slightly different ideas inside a commerce system. The differences matter more for how businesses design and manage promotions than for how customers experience them.

Here’s what each one means:

• Promo codes: These are the specific strings of letters and numbers that customers enter at checkout to activate an offer. They act as the trigger that tells the system which promotion to apply and under what conditions. Promo codes allow offers to be shared selectively, tracked by source, and limited by use, which is harder to do with broad, automatic discounts.

• Coupons: In many systems, a coupon defines the rules of the offer, such as the discount amount, eligibility, and expiration. One or more promo codes are created to redeem that coupon.

• Discounts: Discounts are the outcome, not the mechanism. A discount is the reduced price the customer receives, which can be applied automatically or triggered by a promo code.

Promo codes require customer action, while some discounts apply automatically when conditions are met. Both can result in the same price reduction, but the customer experience is different. Customers often think in terms of “having a code” rather than “receiving a discount.” That sense of access or exclusivity can influence behavior, even when the underlying price reduction is the same.

How Stripe Checkout can help

Stripe Checkout is a fully customizable prebuilt payment form that makes it easy for you to accept payments on your website or application.

Checkout can help you:

• Increase conversion: Checkout’s mobile-optimized design and one-click checkout flow make it simple for customers to input and reuse their payment information.

• Reduce development time: Embed Checkout directly into your site, or direct customers to a Stripe-hosted page, with just a few lines of code.

• Improve security: Checkout handles sensitive card data, simplifying PCI compliance.

• Expand globally: Localize pricing in 100+ currencies with Adaptive Pricing, which supports 30+ languages and dynamically displays the payment methods most likely to improve conversion.

• Use advanced features: Integrate Checkout with other Stripe products, such as Billing for subscriptions, Radar for fraud prevention, and more.

• Maintain control: Fully customize the checkout experience, including saving payment methods and setting up post-purchase actions.

Learn more about how Checkout can optimize your payment flow, or get started today.