Hi,
Hoping someone can help me :)… I’d like to add a Service Fee of 18% to 20% to all orders automatically at checkout… The logic would look something like this.
calculate the total of cart, add item “Service Fee” to cart (can be a product). If total cart value <$1500, Service Fee value =_.20, if total cart value >$1500, service fee value =_.18 of total cart.
And then add a flat $10 local delivery charge.
Any help would be very much appreciated!
Thanks Much!!! 
Hello,
The ‘service fee’ would need to be a product but you will find it difficult to apply exact percentages.
I would create variants of the service fee product to match cart totals with specific service fee prices. You could then have 100 different options to charge as a service fee e.g
variant name: 1000 ($10 - in cents is probably easier)
variant price: $2
variant name: 2000
variant price: $4
etc.
You would then need to use some front-end code to match the current cart total with a variant name and add the correct variant to the cart.
There might be an app that does this if you are not comfortable editing code.
Hey @DaMeatMan, jumping in here (disclosure: I’m the developer of an app called Practical Fees & Surcharges, so factor that in).
The flat $10 local delivery charge is the easy part - that’s just a standalone fixed-fee rule, no code needed, and works in most fee apps including mine.
The tiered 20%/18% service fee is the trickier piece, and it’s worth being precise about why: jordanholmes is right that you can’t get Shopify’s cart to natively evaluate “if subtotal is above/below $1500, use a different %” without either custom code or an app built specifically for conditional/threshold-based rules. His variant workaround technically works but is genuinely painful to maintain (you’d be hand-building a lookup table and syncing it with a script).
What I can confirm my app does: percentage-of-subtotal fees, rule-based conditions (product, tag, etc), min/max caps, and fees that are protected through checkout so customers can’t remove them. What I can’t confirm off the top of my head is whether it currently supports a “different % above vs below a specific cart total” trigger, that’s a more specific condition type than the general product/tag rules, and I don’t want to promise it works before I’ve verified it firsthand.
If that exact threshold-based logic is a dealbreaker, I’d install on a dev store and test the $1499 vs $1501 boundary before committing, rather than take my word for it. Happy to follow up once I’ve actually confirmed that piece.
Free to install: Practical Fees & Surcharges - One app for shipping protection, packaging & any custom fee | Shopify App Store