If you watched my video on building a passive income website with Hostinger Horizons, you saw me go from a blank screen to a fully functional profit calculator in about 10 minutes with zero code.
But a major reason that my utility site was generated so easily was because of the prompt I used.
Hostinger Horizons (and AI builders like it) are powerful, but they’re not mind readers. A vague prompt gives you a vague, half-broken site. A clear, specific prompt gives you something that actually works, and can actually make money.
This cheat sheet gives you two things:
- A fill-in-the-blank prompt template you can use to generate a clean, build-ready prompt for Hostinger Horizons
- A list of 15+ utility website ideas you can plug into that template today
Let’s get into it.
Why Most People’s First Prompt Fails
When people try this for the first time, they usually make one of these mistakes:
- Too vague: “Build me a website that helps online sellers.” (Helps them do what, exactly?)
- Too much at once: Asking for a calculator, a blog, a login system, and a payment portal in one prompt.
- No defined inputs/outputs: The AI doesn’t know what the user is supposed to type in, or what they should get back.
The fix is simple: be specific about function, not features. Tell the AI exactly what the user enters and exactly what the tool gives back. That’s it. Everything else (colors, layout, copy) can be refined after the first draft loads.
One more thing based on my own testing: simple calculators and converters tend to work more reliably than tools that try to “generate ideas” or act like a mini chatbot. If you’re newer to this, start with something that takes numbers in and gives numbers (or a clear result) out. You can always get more ambitious once you’re comfortable with how the tool responds.
The Fill-In-The-Blank Prompt Template
This template is designed to be copied and pasted directly into Claude or ChatGPT. Fill in the blanks with your own idea, then ask Claude or ChatGPT to turn your answers into a clean, ready-to-use Hostinger Horizons prompt.
If you’d rather skip that step so you don’t have to use Claude or ChatGPT, the 15 utility website ideas below this section each come with their own complete prompt. Those are ready to paste directly into Hostinger Horizons as-is, or you can tweak first if you want to make them your own.
I want to build a utility website using Hostinger Horizons.
Tool name: [WHAT DO YOU WANT TO CALL THE TOOL?]
What problem does it solve: [ONE SENTENCE — WHO IS THIS FOR AND WHAT
DECISION OR PROBLEM DOES IT HELP THEM WITH?]
What the user enters (be specific — list every field):
- [INPUT 1, e.g. "Sale price"]
- [INPUT 2, e.g. "Cost of materials"]
- [INPUT 3, e.g. "Shipping cost"]
- [add as many as needed]
What the tool calculates or generates (be specific about the output):
- [OUTPUT 1, e.g. "Total fees"]
- [OUTPUT 2, e.g. "Profit per unit"]
- [OUTPUT 3, e.g. "Estimated monthly profit"]
Design notes (optional, keep simple):
- Style: [e.g. "clean and modern," "minimal," "professional"]
- Color direction: [e.g. "teal and white," "dark navy and gold"]
- Layout: [e.g. "simple input form on one side, results on the other"]
Turn this into a single, clear prompt I can paste into Hostinger Horizons
to build this tool. Keep it focused on function. Example: Filled out using my actual profit calculator
Tool name: Is It Worth It? Seller Profit Calculator
What problem does it solve: Helps online sellers figure out if a product's
price point is actually profitable after fees and taxes.
What the user enters:
- Sale price
- Production/materials cost
- Shipping cost charged to buyer
- Actual shipping cost paid by seller
- Platform fees percentage
- Estimated units sold per month
- Estimated tax rate percentage
What the tool calculates:
- Platform fees
- Total fees
- Profit per unit
- Estimated monthly profit
- Estimated taxes to set aside
- Net monthly take-home after taxes
Design notes:
- Style: clean and modern, professional
- Color direction: teal color palette, avoid "generic AI" look
- Layout: simple input form on the left, results breakdown on the rightThat’s nearly word-for-word what I used in my video tutorial, and Horizons built a fully working calculator on the first try.
Pro tip: Once your first draft loads, you don’t need a new prompt for every tweak. You can just say things like “change the color scheme to dark navy and gold” or “make the results cards bigger” right in the chat. For small text or image changes, you can click directly on the element and edit it without prompting at all.
15 Utility Website Ideas (With Ready-to-Use Prompts)
These are all calculator-style tools with clear inputs, clear logic, clear output. That’s the format Hostinger Horizons handles most reliably. I’ve also tried to keep these a little more fun and unexpected than the usual “tip calculator” content that already floods search results.
Each prompt below is ready to paste directly into Hostinger Horizons. Feel free to tweak the design notes at the end of any of them.
1. Stock Market Goal Calculator Tells you how much to invest monthly to hit a savings goal, based on historical SPY average returns.
Build a web app called Stock Market Investment Goal Calculator. Users enter their monthly savings goal amount, the number of years they plan to invest, and their
current savings (if any). The tool calculates how much they need to
invest monthly to reach that goal, using a default average annual return
of 7% (historical SPY average), with a note that returns are not
guaranteed. Display monthly investment needed, total amount invested,
and estimated growth from returns. Clean, modern design with a simple
input form and a clear results breakdown. Include a disclaimer that this
is for educational purposes and not financial advice.2. Homemade Dog Food Calculator Calculates a balanced homemade meal based on the dog’s weight and selected ingredients, and flags nutritional gaps.
Build a web app called Homemade Dog Food Calculator. Users enter their
dog's weight, and select ingredients from checkboxes grouped into
categories: proteins (chicken, beef, turkey, fish), carbs (rice, sweet
potato, oats), and vegetables (carrots, green beans, spinach, pumpkin).
The tool calculates the appropriate portion size of each selected
ingredient based on the dog's weight, and displays a results section
highlighting any nutritional gaps (such as low protein or missing
vegetables) and any ingredients that may be excessive. Clean, friendly
design with a simple checklist on one side and results on the other.
Include a disclaimer to consult a vet before changing a dog's diet.3. Freelance Hourly Rate Calculator Calculates what hourly rate a freelancer needs to charge to hit their income goal.
Build a web app called Freelance Hourly Rate Calculator. Users enter
their desired annual income, estimated unpaid hours per week (for admin,
marketing, etc.), billable hours per week, and weeks taken off per year.
The tool calculates the hourly rate needed to reach their income goal,
along with their effective weekly and monthly income at that rate.
Clean, professional design with a simple input form and a clear results
summary.4. Sponsorship Rate Calculator Calculates a fair sponsorship rate for content creators based on engagement.
Build a web app called Sponsorship Rate Calculator. Users enter their
follower count, average views per post, average likes and comments per
post, and platform (Instagram, YouTube, or TikTok). The tool calculates
their engagement rate and uses it to estimate a fair sponsorship rate
range for a single sponsored post. Display engagement rate percentage
and the estimated rate range clearly. Clean, modern design with a simple
input form and results displayed in cards.5. Baby Zodiac Calculator Tells users the best conception window to have a baby born under a chosen zodiac sign.
Build a web app called Baby Zodiac Calculator. Users select a desired
zodiac sign for their future baby from a dropdown. The tool calculates
the date range they would need to conceive in order for the baby to be
born within that zodiac sign's date range (using a standard 40-week
pregnancy estimate), and displays the recommended conception window.
Fun, playful design with star-themed visuals and a simple dropdown
selector.6. Coffee Brew Ratio Calculator Calculates the exact coffee-to-water ratio for different brewing methods.
Build a web app called Coffee Brew Ratio Calculator. Users select a
brewing method (pour over, French press, cold brew, or espresso) and
enter how many cups they want to make. The tool calculates the exact
amount of coffee grounds (in grams) and water (in ml or oz) needed based
on standard ratios for that brewing method. Clean, minimal design with a
dropdown selector and a simple results card.7. Houseplant Watering Calculator Tells users how often to water a houseplant based on plant type, pot size, and light conditions.
Build a web app called Houseplant Watering Calculator. Users select
their plant type from a dropdown (such as succulent, pothos, fiddle leaf
fig, snake plant, monstera), their pot size, and the amount of light the
plant receives (low, medium, bright indirect, direct sun). The tool
calculates a recommended watering frequency and displays a simple care
tip specific to that plant type. Clean, natural design with green
accents and a simple dropdown-based form.8. Road Trip Cost Splitter Calculates each person’s share of a road trip’s total cost.
Build a web app called Road Trip Cost Splitter. Users enter total miles
driven, their car's average miles per gallon, current average gas price,
any additional costs such as tolls or parking, and the number of people
splitting the trip. The tool calculates total trip cost and the amount
each person owes. Clean, simple design with an input form and a clear
per-person cost breakdown.9. Houseplant Repotting Timer Tells users when their plant is due for a new pot based on plant type and last repot date
Build a web app called Houseplant Repotting Timer. Users select their
plant type from a dropdown (such as pothos, snake plant, monstera,
fiddle leaf fig, succulent, fern) and enter the date they last repotted
it. The tool calculates when the plant is next due for repotting based
on that plant type's typical growth rate, and displays the recommended
next repot date along with a simple status message (such as "due now,"
"due soon," or "not due yet"). Clean, natural design with green accents
and a simple dropdown-and-date input form.10. Wedding Budget Allocator Splits a total wedding budget across categories based on standard percentage guidelines.
Build a web app called Wedding Budget Allocator. Users enter their total
wedding budget. The tool splits the budget across standard categories
(venue, catering, photography, attire, flowers, music/entertainment,
and miscellaneous) using typical percentage guidelines, and displays a
breakdown of how much to allocate to each category. Elegant, simple
design with the input field at the top and a clear category-by-category
breakdown below.11. Moving Cost Estimator Estimates the total cost of a move based on distance, home size, and whether movers are hired.
Build a web app called Moving Cost Estimator. Users enter their move
distance in miles, home size (studio, 1-bedroom, 2-bedroom, 3+ bedroom),
and whether they plan to hire movers or move themselves. The tool
calculates an estimated total moving cost range based on these inputs,
and displays a simple breakdown of what's driving the cost. Clean,
modern design with a simple form and a clear results card.12. Pet Age Calculator Converts a dog or cat’s age into human years, adjusted for breed size (more accurate than the generic “multiply by 7” method).
Build a web app called Pet Age Calculator. Users select whether their
pet is a dog or cat, enter the pet's age, and for dogs, select a size
category (small, medium, large, giant breed). The tool calculates the
pet's age in human years using a non-linear aging scale appropriate to
the pet's size and species, and displays the result with a short fun
fact about pet aging. Friendly, playful design with a simple form and a
clear result display.13. Skincare Routine Builder Builds a simple AM/PM skincare routine based on skin type and main concern.
Build a web app called Skincare Routine Builder. Users select their skin
type (oily, dry, combination, sensitive) and their main skin concern
(acne, anti-aging, hydration, dark spots) from dropdowns. The tool
generates a recommended morning and evening skincare routine, listing
the general product type for each step (such as cleanser, treatment,
moisturizer, SPF) in order. Clean, modern design with two dropdown
selectors and the routine displayed in a clear step-by-step list.14. Sourdough Starter Feeding Calculator Calculates how much flour and water to feed a sourdough starter based on its current size and desired ratio.
Build a web app called Sourdough Starter Feeding Calculator. Users enter
the current weight of their starter and select a feeding ratio (1:1:1,
1:2:2, or 1:5:5). The tool calculates the exact amount of flour and
water (in grams) needed for that feeding, and displays the total weight
after feeding. Clean, simple design with a rustic feel, a basic input
form, and a clear results display.15. Houseplant Fertilizer Dosage Calculator Calculates how much fertilizer to use based on plant type and pot size.
Build a web app called Houseplant Fertilizer Dosage Calculator. Users
select their plant type from a dropdown and enter their pot size in
inches. The tool calculates the recommended amount of liquid fertilizer
to dilute per watering, along with how often to fertilize based on
season. Clean, natural design with green accents and a simple
dropdown-and-input form.When picking one to build, ask yourself: Is this something people are already actively searching for, or would actively share? That’s what drives the free, repeat traffic that makes AdSense actually worth it.
Your Next Steps
- Pick one idea from the list above (or use your own)
- Use the template provided to write a prompt
- Type your prompt into Hostinger Horizons
- Refine your site in the chat until it looks perfect
- Hit publish & start monetizing
If you want to build along with the exact process from my video, you can try Hostinger Horizons here: hostinger.com/savage use code SAVAGE at checkout for an additional 10% off the Starter plan.