Shopify Bundle Pricing: Percentage vs Fixed Discount

Use a percentage discount when the savings rate should stay constant as the eligible product price changes. Use a fixed amount per item when the dollar saving on each discounted unit should stay constant. Use a custom total when the offer itself is an exact headline such as “Buy 3 for $72.”

None of those choices tells you how deep the discount should be. Approve the quantity and profit-safe tier total first. Then convert that same total into each pricing format and choose the rule you are prepared to maintain.

Kaching Bundles & Upsells is a direct fit for this decision because its Quantity Break setup supports percentage or fixed-amount discounts per item and a custom total for the selected quantity. The worksheet below helps you choose among those controls before you publish the offer.

⚡ ShopSideK Verdict

Choose percentage when: You want the discount rate to follow the eligible price. A 20% offer remains 20%, but the amount the shopper pays moves when the product price moves.

Choose fixed amount per item when: You want to keep a specific dollar saving on every discounted unit. The saving stays fixed, but the bundle total does not.

Choose custom total when: “Buy X for $Y” is the offer. The headline total stays fixed, but the effective discount percentage and contribution can change after a catalog-price update.

Kaching fit: Quantity Break gives you all three inputs. Kaching does not decide which total is profitable or guarantee an untested mixed-variant, market, subscription, or discount-stack result.

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The short decision table

This table assumes the discount is already economically acceptable. If you have not set a contribution floor or maximum safe discount, do that before choosing how the discount appears in the app.

Normalize all three methods to the same approved total

Comparing 20% off with $6 off and “3 for $72” is useful only when all three produce the same starting price. Otherwise, you are changing the discount depth and the presentation at the same time.

For an equal-price quantity tier, record:

• q: quantity in the tier;
• P: regular eligible unit price;
• T: approved tier total.

Then calculate:

Regular total = q × P

Equivalent percentage discount = (regular total − T) ÷ regular total

Equivalent fixed amount per item = (regular total − T) ÷ q

Custom total = T

Enter only the precision your bundle editor supports, then calculate the achieved total again. A mathematically exact percentage can miss the intended total if the input or line prices must be rounded.

Worked example: three units for $72

Assume one unit normally costs $30, the tier quantity is three, and your approved tier total is $72.

• Regular total: 3 × $30 = $90
• Percentage setting: 20% off
• Fixed-amount setting: $6 off each unit
• Custom-total setting: $72

At this baseline, all three methods charge $72 before tax, shipping, another discount, subscription pricing, currency handling, or an app-specific interaction.

That is the fair comparison point. You can now choose a format by asking what should happen when the $30 price no longer stays $30.

What each pricing format actually keeps constant

Percentage discount: keep the rate

A percentage follows the eligible price. If the product goes from $30 to $32, a 20% discount still removes one-fifth of the regular total. Both the dollar saving and the amount paid increase.

Percentage is the cleanest starting candidate when:

• product or variant prices change regularly;
• the same relative saving should apply across eligible price points;
• a specific “3 for $72” total is not part of the promise;
• your team prefers to maintain one rate rather than several currency amounts.

It is a weaker fit when your creative, landing page, or ad promises an exact bundle total. A 20% tier on a changing product price cannot also guarantee “3 for $72.”

Fixed amount per item: keep the dollar saving

Kaching describes this Quantity Break option as a fixed discount per item. If the setting is $6 off each unit, three discounted units receive $18 off in total.

That is not the same as fixing the final bundle price.

At a $30 regular unit price, $6 off produces $24 per unit and $72 for three. If the regular price rises to $32, the same setting produces $26 per unit and $78 for three. The dollar saving remains $18, while the effective percentage falls from 20% to 18.75%.

Fixed amount per item is a sensible starting candidate when:

• “save $6 on each” is the intended message;
• the absolute allowance per discounted unit matters more than a fixed rate;
• eligible prices sit within a controlled range;
• the team will review the offer after price or market changes.

Do not label this method “3 for $72” unless the current calculation really produces $72 and your change process protects that claim.

Custom total: keep the headline price

A custom total is the natural candidate when the offer is “2 for $50,” “3 for $72,” or another exact selected-quantity price.

The trade-off is economic drift. If the regular price rises while the custom total stays at $72, the shopper receives a deeper effective discount. If the regular price falls, the deal becomes weaker and can eventually stop being a discount at all.

Use a custom total when:

• the exact bundle total is easier to communicate than a rate;
• paid creative or merchandising relies on one clean price;
• the eligible products and variants have a tested pricing structure;
• someone owns the review triggered by catalog-price changes.

Do not assume that a custom total will behave the way you expect across differently priced variant combinations. Kaching’s current Quantity Break documentation confirms the custom-total control, but it does not document every mixed-price outcome. That requires storefront, cart, and checkout evidence from your own setup.

See price drift before it reaches checkout

The table below keeps the three baseline settings unchanged: 20% off, $6 off each unit, and a $72 custom total.

The custom-total column models a configured $72 value that has not been changed. It is not evidence that Kaching will resolve every differently priced variant combination to that amount.

At $32 per unit, the $72 custom total is effectively 25% off. At $28 per unit, it is about 14.29% off. The displayed total is stable, but the discount depth is not.

The opposite happens with percentage pricing: the 20% depth is stable, but the total moves from $67.20 to $76.80. Fixed amount sits between those rules—it preserves $6 per unit and lets both the rate and final total move.

There is no universal winner in this table. The right choice is the rule that preserves the part of the offer you actually need to keep constant without violating the approved contribution floor.

Do not let a pricing-psychology rule override the economics

Many discount articles reduce this decision to a rule such as “use dollars below one price point and percentages above it.” That can be a framing hypothesis. It is not evidence that one format will convert better on your products, traffic, and offer.

Start with equivalent economics. If 20% off, $6 off per item, and “3 for $72” all produce the same baseline total, you can compare the messages without quietly paying for a deeper discount in one version.

Before treating the copy as the variable, hold these elements constant:

• eligible product and variants;
• quantity and final baseline price;
• placement and default tier;
• traffic source and audience;
• other promotions;
• measurement window and business-cycle coverage;
• primary outcome, preferably contribution profit per eligible visitor rather than AOV alone.

If you cannot make the economics equivalent because of rounding or app constraints, record the difference. A test that compares both framing and discount depth cannot tell you which change caused the result.

Handle rounding, variants, and Markets explicitly

Odd-cent totals

Suppose three units cost $19.99 each and you want a $49.99 tier.

• Regular total: $59.97
• Exact equivalent percentage: approximately 16.6417%
• Exact fixed saving per item: approximately $3.3267

An editor that accepts less precision can land above or below $49.99 after rounding. A custom total is the clearer candidate for the exact headline, but you still need to check the value shown on the product page, cart, and checkout.

Do not hide a one-cent discrepancy in the savings copy. Decide the allowed tolerance, document it, and make all customer-facing totals agree.

Differently priced variants

Variant spread changes the risk.

A percentage normally scales with the eligible price basis. A fixed amount gives the same dollar reduction to a low- and high-priced eligible unit. A custom total may imply a much deeper discount on a premium selection—or the app may apply its own rule to the chosen variants.

Do not infer the outcome. Test:

1. the lowest-priced eligible variant;
2. the highest-priced eligible variant;
3. each allowed mixed-price combination that can materially change contribution;
4. the exact quantities and discount lines in cart and checkout.

If you cannot state which items qualify, how the selected prices form the regular total, and what the shopper will be charged, hold the offer.

Markets and currencies

Shopify documents that its percentage discounts apply to the shopper’s local price, while fixed amounts are created in the store’s default currency and converted at checkout. The converted fixed amount can move with the exchange rate.

That platform rule is a reason to test each active market. It is not proof of how every Kaching custom-total configuration works internally.

For a secondary market, record:

• the contextual regular price;
• the currency displayed;
• the configured bundle method;
• the product-page total and savings;
• the cart discount lines;
• the charged checkout total;
• the contribution result in your approved finance basis.

Kaching can limit a deal to selected Shopify Markets. If one global pricing rule does not produce an acceptable local result, a separate market-targeted deal can be more controlled than forcing one format everywhere.

Run the 12-case Price Drift Matrix

An app preview confirms that you entered a setting. It does not prove the complete purchase path.

Use three release states:

• PASS: The method produces the approved result across every material case.
• REVISE: The architecture is sound, but the value, message, eligibility, or price method must change and be retested.
• HOLD: An undocumented interaction, failed contribution floor, misleading saving, or checkout mismatch remains.

Do not average away a failure. If the premium variant misses the contribution floor or one market charges a different total, exclude that state or revise the offer before launch.

Where Kaching fits—and where it does not

Kaching is a practical fit when you want a visible product-page Quantity Break and need to choose between the three methods in this article. Its current Quantity Break documentation states that the offer can use:

• a percentage discount per item;
• a fixed amount discount per item;
• a custom total price for the selected quantity.

That gives you an implementation path inside Kaching’s Quantity Break setup. It does not remove the commercial decisions around the control.

Use this sequence:

1. Approve the quantity and profit-safe tier total outside the app.
2. Calculate the equivalent percentage and fixed amount per item.
3. Choose what should remain constant.
4. Configure that candidate in a Quantity Break.
5. Make the tier label describe the actual math.
6. Run the 12-case matrix before sending traffic.

Do not carry the same calculation into a Buy X Get Y offer without rebuilding it. Kaching’s current BXGY guide applies percentage, amount-off, fixed-price, or free treatment to the discounted Y item. That is a different pricing question from setting the total for a Quantity Break tier.

Kaching is not the complete answer when:

• you still need to calculate the safe discount;
• a true bundle product and inventory architecture is required;
• the price must follow undocumented custom rules;
• mixed variants, subscriptions, Markets, or other discounts have not passed QA;
• you need proof that one framing causes higher conversion.

If Quantity Break is the right architecture and the matrix is feasible, you can claim 20% OFF Kaching for your first 3 months. If you prefer to inspect the listing first, you can also view Kaching on the Shopify App Store.

When native Shopify Bundles is the better architecture

A custom-total Quantity Break and a fixed bundle product are not interchangeable.

Shopify Bundles is the more direct candidate when you need a fixed bundle or multipack represented as its own parent bundle product, with components handled through Shopify’s bundle architecture.

That route has a different maintenance trade-off. Shopify states that changing a component product’s price does not update the bundle price automatically; the merchant must update the bundle price manually. Discounts on the parent bundle are also allocated to components by weighted price.

Choose the architecture before the pricing field:

• Use a Quantity Break when the shopper is choosing a multi-unit deal on the product page.
• Use a fixed bundle product when the set should be sold and managed as a bundle product.
• Use BXGY when the commercial promise is defined around the discounted Y item.

Trying to force all three offers into the same price calculation creates more confusion than choosing the correct mechanic first.

Final decision checklist

1. Approve the tier quantity and total with your existing contribution guardrail.
2. State what should remain constant: discount rate, saving per unit, or final bundle total.
3. Calculate the equivalent percentage and fixed amount per item.
4. Check whether rounding prevents an exact comparison.
5. Choose one candidate format.
6. Test base-price increases and decreases.
7. Test low, high, and mixed-price variants where applicable.
8. Test every material market, selling plan, and discount interaction.
9. Reconcile product page, cart, and checkout.
10. Assign an owner and a review trigger for catalog-price changes.

The result is not “percentage is best” or “custom total converts better.” It is a pricing rule that preserves the intended part of the offer and has passed the states your customers can actually buy.

Frequently asked questions

Is a percentage or fixed discount better on Shopify?

Neither is universally better. Percentage preserves the relative discount rate as the eligible price changes. Fixed amount preserves the dollar saving. Compare them at the same approved starting total, then choose based on maintenance, variants, Markets, and the message you need to keep accurate.

What is the difference between fixed amount per item and custom total?

A fixed amount per item subtracts the same dollar amount from each discounted unit. The final bundle total changes when the regular unit price changes. A custom total sets the selected quantity to a named total, so its effective percentage changes when the regular price moves.

Does a custom total stay profitable when product prices change?

Not automatically. A higher regular price makes the same custom total a deeper effective discount; a lower regular price makes it a weaker discount. Recheck the contribution floor whenever the underlying price or eligible variant mix changes.

Can Kaching use percentage, fixed amount, and custom total?

Kaching’s current documentation confirms all three for Quantity Break: percentage or fixed amount per item, or a custom total for the selected quantity. Its BXGY and Bundle Upsell mechanics use different pricing structures, so do not assume the same calculation transfers unchanged.

How should I price bundles with differently priced variants?

Build the regular total from the exact variants the shopper can select. Test the lowest, highest, and material mixed-price combinations. Do not publish a custom total until its storefront, cart, checkout, and contribution behavior are reproduced for those selections.

How this guide was researched

ShopSideK reviewed current Shopify and Kaching documentation on July 26, 2026, including a conflict between older and newer Kaching BXGY instructions. The equivalence worksheet, price-drift examples, and release matrix are ShopSideK editorial models. All numbers are hypothetical and are not presented as store results or conversion predictions.