Momyknows Discount Code SAVE30 is a public discount code for the maternity fashion brand Momyknows, advertised as giving up to 30% off when you type SAVE30 into the promo field at checkout on momyknows.com. Most of the time it applies without drama. When it does not, the failure is almost always one of a small number of predictable causes — a stray character, the wrong website, a basket that does not qualify, or a reduction that landed lower than expected rather than not landing at all. This article works through each one in turn and gives you the fix.
Start by separating three different problems
Shoppers tend to describe any disappointing checkout as "the code didn't work", but there are three distinct outcomes and each needs a different response.
Outright rejection. The field returns an error and no discount line appears in the order summary. Something about the string, the site or the basket blocked it.
Silent non-application. The page seems to accept the code, but the subtotal does not move and there is no discount line. Usually the code has attached to nothing eligible, or the page never submitted it.
Smaller discount than expected. A discount line appears but the reduction is well under 30%. This is not a fault. SAVE30 is advertised as up to 30%, and "up to" is a ceiling rather than a promise.
Only the first two are errors you can fix. The third is the offer behaving as written, and the correct response is to judge the order on the total shown rather than on the headline.
Cause 1: an invisible character in the code
This is the single most common reason a valid discount code is refused. Copying SAVE30 from a page frequently drags along a trailing space, and a promo field treats "SAVE30 " as a different string from "SAVE30". Nothing on screen shows you the difference, which is why the error looks inexplicable.
The fix is to stop pasting. Clear the field completely, then type the eight characters — S, A, V, E, 3, 0 — by hand, with no space before or after. Codes are usually case-insensitive, so lowercase is normally fine, but typing it in capitals removes one more variable. If your keyboard software autocorrects or capitalises unpredictably, check the field reads exactly SAVE30 before you press apply.
A related version of this problem is entering the code into the wrong box. Some checkouts sit a gift card or store credit field next to the discount field, and a percentage code entered into a gift card box will always fail. Read the label: you want the one marked discount code, promo code or coupon.
Cause 2: you are on a similar-sounding but different website
The spelling of the brand is easy to get wrong, and getting it wrong is fatal to the code. It is Momyknows — one "m" in the middle — at momyknows.com. There is a separate company with a similar-sounding name that sells maternity health supplements, and it is an unrelated business. SAVE30 will not apply on that site, and no amount of retyping will change that.
The quick diagnostic is the catalogue. Momyknows sells clothing for expectant mothers: dresses, gowns, jumpsuits, tops, bottoms, nursing apparel, swimwear and cover-ups. If the products in front of you are supplements rather than garments, you are on the wrong site. Check the address bar letter by letter before you build a basket, not after the code has been refused.
Cause 3: the code never actually got submitted
On plenty of stores the discount field lives inside a collapsible panel beside the order summary, or only appears on the payment step. Typing a code into a partially open panel and then scrolling past it is enough to lose the entry entirely. There is often also a separate apply button that must be pressed — pressing the main pay button instead can either discard the code or complete the order without it.
Expand every collapsed panel on the cart and checkout pages until you can see the field labelled discount, promo or coupon.
Type SAVE30 into that field.
Press the apply or arrow control attached to the field, not the payment button.
Wait for the page to refresh the order summary before doing anything else.
Confirm a named discount line has appeared and that the subtotal has changed. A confirmation message on its own is not proof; the number is.
If the summary shows no discount line after applying, the code either did not submit or did not attach to anything in your basket. Reload the checkout, re-enter it once, and if the result repeats, move on to the basket-level causes below.
Cause 4: basket conditions you cannot see in advance
Several of the conditions that would normally explain a rejection are not published anywhere reliable for SAVE30. It is not known whether the code excludes sale items, nursing bras, swimwear or plus sizes. It is not known whether there is a minimum spend, an expiry date, or a first-order-only restriction. That is frustrating, but it also means you can diagnose by experiment rather than by reading terms.
Percentage codes are commonly written so they cover some categories and not others, or so they scale with basket value. So if SAVE30 is refused or applies to nothing, try isolating your basket. Remove anything discounted or clearance-looking and apply the code again. If it then works, an exclusion on reduced items is the likely explanation and you can decide whether the sale price or the discounted full price leaves you better off.
If the code is refused on a very small basket, a minimum spend is a plausible cause. The catalogue is broad enough to build a larger order honestly rather than adding filler: baby shower dresses, gowns and jumpsuits including plus sizes; photoshoot dresses in lace, boho, beach, mesh and sequin styles; gender reveal outfits in pink, blue, white and mixed colourways; general maternity tops, bottoms, dresses and jumpsuits; nursing tops, bras, dresses and pyjamas; and maternity swimwear with cover-ups. Combining a gender reveal outfit with a set of nursing pyjamas is a realistic single order, not a stretch.
Cause 5: the discount worked but the shipping changed
This one is not a rejection at all, yet it produces the same feeling of the code failing. Momyknows states free shipping on orders of $79 or more, which also tells you prices are in US dollars. A percentage code reduces your subtotal, and a lower subtotal can drop you back under that line.
So if your pre-discount basket sits a little above $79, check whether the post-discount figure still clears it. If it does not, a shipping charge can reappear and eat into the reduction you just gained. It is also not clear whether SAVE30 interacts in any way with that shipping threshold, so the only reliable test is to look at the final total with both lines visible. If the saving after shipping is smaller than the shipping charge you triggered, consider whether adding one more item you genuinely want puts you back above the threshold.
Cause 6: you are expecting the wrong kind of code
Some rejections are really misunderstandings about what SAVE30 is. It is a discount code: a short alphanumeric string shared publicly, which anyone who knows it can type in. It is not tied to your identity, your email address or anyone who introduced you to the shop.
It is not a referral code. Referral codes are personal to an existing customer and usually reward two people. There is no friend to credit here and no reciprocal reward, so do not look for a referral field.
It is not a voucher in the gift-certificate sense. A voucher normally carries a fixed cash value you spend down. SAVE30 is a percentage reduction, so its value scales with your basket instead of being fixed.
If you see it called a coupon, that is the same thing as a discount code. The different name does not mean a different offer, and it does not mean you have the wrong string.
Because it is a public code, you do not need an account relationship, an invitation or a prior order to try it. If a page tells you to sign in before the discount field appears, that is the store's checkout design rather than a condition of the code.
Cause 7: the real problem is fit, not the code
A discount that applies perfectly still fails you if the garment does not fit. Maternity sizing changes as a pregnancy progresses, and guessing is the most common cause of a return. A dress that fits at one stage may not fit weeks later, which makes the size guide more consequential here than on most clothing sites.
Momyknows publishes a size guide at /pages/size-guide and a returns and refund policy at /pages/return-and-refund. Read both before you order. The specific return window, whether sale items can be sent back, and the measurement details are things to confirm on those pages directly rather than assume. If you are uncertain about sizing and have not checked the returns terms, the discount is not the variable that decides whether the purchase works out.
A short troubleshooting order of operations
Confirm you are on momyknows.com, spelled with one "m" in the middle, and that the products are clothing.
Type SAVE30 by hand into the field labelled discount, promo or coupon. No spaces, no pasting.
Press the field's own apply control and wait for the order summary to refresh.
Look for a discount line and a changed subtotal, not just a confirmation message.
If nothing applies, remove sale or clearance items and try once more.
If it is still refused on a small basket, consider that a minimum spend may exist and consolidate items you actually need.
Check the final total against the $79 free shipping threshold before paying.
Judge the offer on the number on screen. Pay only when that total is one you are happy with.
The honest summary is that SAVE30 is a straightforward public code with an unusually thin published rulebook. Its strength is the breadth of the catalogue, which spans event dressing, everyday maternity wear, nursing apparel and swimwear, so a basket that justifies the code is easy to assemble. Its weakness is that exclusions, minimum spend and expiry are not published, so you cannot calculate your saving in advance. A 30% reduction means paying 70% of the pre-discount figure, and that is the best case rather than the guaranteed one. Work through the checks above, and if the number barely moves you have lost nothing but the few seconds it took to type eight characters.
Promotional terms, eligibility and values are set by the provider and can change at any time. Always confirm the current terms on the official site before signing up or completing a purchase.