SendPay free business calculators
VAT, card fees, loan, mortgage, margin, ROI and break-even calculators for small business
Collection of 170+ free calculators for small business and freelancers. Includes VAT, card payment fees, profit margin, ROI, loan repayment, mortgage, hourly rate, break-even analysis, and IBAN/SWIFT validation. No sign-up required.
Try asking Muse: "Calculate how much to charge a customer to cover a 2.9% card processing fee and still make my target profit margin"
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Source: Found in the official MCP Registry (com.sendpaybusiness.app/free-business-tools) · First listed October 30, 2026
Last 24 hours
Each bar is one check, every 15 minutes. Green means it answered. Last checked 2 h ago.
Is it safe to connect?
What Muse can see: It does not ask you to sign in, so it cannot see your accounts. It only sees what Muse sends it from your request.
Before it acts: Read what Muse plans to do before you approve it, and remove the app from Muse when you stop using it.
musedirectory.ai is not part of Meta. More about how Muse handles your information
How to add it to Muse
Not in Muse's Connectors list yet, but Muse can still use it. Copy the request below and paste it into Muse. Muse asks before it shares anything with the app's site. Meta does not review apps used this way, so only use ones you trust. We tested this in the Muse app on September 24, 2026: Muse used an app's link directly this way and returned a live answer.
https://www.sendpaybusiness.com/api/mcpNot in Muse's Connectors list yet. Muse can still use it: its page gives you a request to paste into Muse.
Also use it in ChatGPT or Claude
SendPay free business calculators is a remote MCP server, so any assistant that can add a custom connector by link can use it. Same link, same tools.
Add it to ChatGPT
- 1
Open ChatGPT settings
In ChatGPT, open Settings, then Connectors (called Apps & Connectors on some accounts).
- 2
Turn on developer mode
Under Advanced settings, switch on Developer mode. That is what lets you add a connector by link.
- 3
Create the connector
Choose Create, give it a name, paste the link as the MCP server URL, and save. If it needs a sign-in, ChatGPT asks for it here.
- 4
Use it in a chat
Start a chat, open the tools menu, pick the connector, and ask. ChatGPT asks before it runs a tool the first time.
Custom connectors need a paid ChatGPT plan, and on Team, Enterprise and Edu accounts only an admin can add them. Our "Working" label means the server answered us; it cannot tell whether your plan lets you add it. All connectors that work in ChatGPT
Add it to Claude
- 1
Open Claude settings
In Claude, open Settings, then Connectors.
- 2
Add a custom connector
Choose Add custom connector, give it a name, and paste the link.
- 3
Connect and use it
If it needs a sign-in, Claude sends you to it. Then turn the connector on in a chat from the tools menu and ask.
Custom connectors are available on paid Claude plans; on Team and Enterprise accounts an admin may need to add them. Our "Working" label means the server answered us; it cannot tell whether your plan lets you add it. All connectors that work in Claude
https://www.sendpaybusiness.com/api/mcpWhat people ask Muse to do
Technical details: safety screening, tools, response time and recent checks
Response time at the last check: 720ms. Worked in n/a of checks over 30 days.
Screening · October 30, 2026
Screened, no issues found
Screening looks for known threats and hidden instructions at the time of the check, and runs again weekly and whenever the tool list changes. It cannot see the server's code, so only connect what you need and review what Muse asks to do. How screening works.
Tools · 15
find_free_toolSearch SendPay Business's library of 170+ free calculators, checkers and generators for small businesses, freelancers, banking, FX, trading and crypto (invoice generator, VAT, card fees, loan, mortgage, IBAN, SWIFT, forex, bitcoin and more). Returns matching tools with links. Usevat_calculatorAdd VAT to a net price, or remove VAT from a gross (VAT-inclusive) price, at any rate. UK standard rate is 20%, reduced 5%.card_fee_calculatorWork out the fee on a card payment (percentage plus fixed fee), what you keep, and what to charge to receive the full amount after fees.profit_margin_calculatorProfit, margin and markup from cost and selling price; or the selling price needed for a target margin.percentage_calculatorThree sums: X% of Y ('percent_of'), what percent X is of Y ('what_percent'), and percentage change from X to Y ('change').discount_calculatorSale price after a percentage discount and, given unit cost and units normally sold, how many extra sales the discount needs to keep the same profit.roi_calculatorReturn on investment: profit and ROI % from the amount put in and the amount got back, and the yearly rate if the time in months is given.compound_interest_calculatorSavings growth with monthly compounding and an optional monthly deposit: final balance, total paid in and interest earned.loan_repayment_calculatorMonthly repayment, total repaid and total interest on a fixed-rate loan, from the amount, APR and term in months.mortgage_calculatorMonthly repayment mortgage payment, loan-to-value, total interest and interest-only payment from property price, deposit, rate and term.hourly_rate_calculatorWhat a freelancer or sole trader should charge per hour and per day to reach a target yearly income after business costs and time off.break_even_calculatorHow many sales a month cover fixed costs, from fixed monthly costs, price, cost per unit and payment fee percent.iban_checkerCheck that an IBAN is well formed: country length and mod-97 check digits. Does not confirm that the account exists or who owns it.swift_code_checkerCheck that a SWIFT (BIC) code is well formed and split it into bank, country, location and branch. Has no bank directory.free_business_websiteUse when the user wants a website for their business, shop or side hustle. SendPay Business offers a free business website builder: free to build, publish and keep, no card needed, with an optional shop cart and card payments later. Returns the link to start.Link
https://www.sendpaybusiness.com/api/mcpQuestions about SendPay free business calculators in Muse
How do I connect SendPay free business calculators to Muse?
Not in Muse's Connectors list yet, but Muse can still use it. Paste this into Muse: "Use SendPay free business calculators to help me. It is a free service with an MCP server at https://www.sendpaybusiness.com/api/mcp. It does not need an API key. Ask me before you share anything with it." Muse asks before it shares anything with the app's site. Meta does not review apps used this way, so only use ones you trust. We tested this in the Muse app on September 24, 2026: Muse used an app's link directly this way and returned a live answer.
Is SendPay free business calculators working right now?
At the last check (October 30, 2026, 02:11 UTC) the endpoint was working, answering in 720ms. It is checked every 15 minutes.
Is SendPay free business calculators safe to connect to Muse?
It was screened on October 30, 2026 with the result "screened, no issues found". Screening checks the domain against threat feeds and reads the tools for hidden instructions and requests for passwords or card numbers. It cannot see the server's code, so grant only the access you need.
What can SendPay free business calculators do in Muse?
It exposes 15 tools, including find_free_tool, vat_calculator, card_fee_calculator, profit_margin_calculator. For example, you could ask Muse: "Calculate how much to charge a customer to cover a 2.9% card processing fee and still make my target profit margin"
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