SignalsOp
Simple tools that do one thing well
Free financial calculators and developer tools that run in your browser. No accounts, nothing to install, and what you type stays on your device.
SignalsOp is a collection of free, single-purpose web tools published by SignalsOp. Each tool is a small page built to answer one question well: what a loan will cost per month, how much to set aside for quarterly taxes, whether renting or buying comes out ahead, or what time it is in another city. Everything is meant to open quickly on a phone and to be clear enough that you can see how the answer was reached.
The tools are privacy-first. Calculations run in your browser, so the numbers and names you enter stay on your device and are not uploaded to our servers. There are no accounts and nothing to install, and we do not ask for personal details to use a calculator. Questions or suggestions can go to contact@signalsop.com.
Tools
Money & finance
Calculators for the money decisions most people face: borrowing, saving, paying down debt, planning retirement and estimating taxes. Each one lets you change a rate, a term or a balance and see right away how the result moves.
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Loan Calculator
Payments, amortization, loan comparison, NPV, IRR and future value.
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Savings Calculator
Compound interest for savings accounts, with FDIC national average rates.
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FIRE Calculator
Find the age you could reach financial independence.
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Freelance Tax Estimator
Quarterly estimates, take-home pay by state, and guides to deductions and deadlines.
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Life Insurance Estimator
Estimate how much term coverage your family may need.
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Mortgage Tools
Rent vs. buy, refinance break-even, HELOC and DTI calculators, plus buying-cost and PMI guides.
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Debt Payoff Tools
Money snapshot dashboard, avalanche vs. snowball, balance transfers and credit utilization.
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Retirement Tools
Monte Carlo withdrawal simulator, Roth vs. Traditional, 401k match, HSA, Social Security and RMDs.
Everyday
A fair, private way to organize a gift exchange. Names are drawn in your browser and never uploaded.
Developer tools
Utilities for people who write and publish code: format and check JSON, convert between number bases, generate structured data for search engines and compare hosting costs. Anything you paste is processed locally in your browser.
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JSON Formatter
Format, validate and minify JSON with exact error locations.
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Programmer Calculator
Hex, binary, octal and decimal, bitwise operations, floats and timestamps.
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Schema Markup Generator
JSON-LD for FAQ, recipe, product, article, event and how-to pages.
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☁️
Cloud Cost Calculator
Compare server costs on AWS, Azure, Google Cloud and DigitalOcean.
Time & clocks
Compare times across cities before scheduling a call. Everything runs in your browser.
Popular calculators
- US tax calculators: quarterly estimates, take-home pay by state, brackets and capital gains.
- Loan calculator: monthly payments, amortization schedules and side-by-side loan comparison.
- Retirement tools: withdrawal simulator, Roth vs. Traditional, 401k match, HSA, Social Security timing and RMDs.
- Mortgage tools: rent vs. buy, refinance break-even, HELOC payments and debt-to-income ratio.
- Debt payoff tools: money snapshot, avalanche vs. snowball, balance transfers and credit utilization.
How we build and check our tools
Where a tool depends on published figures, we use the official source. The US tax tools use figures from IRS revenue procedures for tax years 2025 and 2026 and Social Security Administration wage base announcements. The retirement tools use the IRS Uniform Lifetime Table for required minimum distributions. The savings calculator offers national average rates from the FDIC’s published national rates, shown with the date they were taken. Cloud cost figures carry the date they were collected.
The math itself, such as amortization, compound interest and bracket calculations, is kept in plain code separate from the page layout, and each tool has automated tests that check it against known examples. Rates, limits and prices change, and we update the figures by hand when we notice a change or hear about one, so we do not promise a fixed update schedule. If a number looks out of date, please tell us and we will check it against the source.
Not financial, tax or legal advice. The calculators give estimates for learning and planning. Real outcomes depend on details these tools cannot see, such as your full tax situation, lender fees and future rates. For decisions that matter, check the result with a qualified professional or the official source.
Frequently asked questions
- Are the tools really free?
- Yes. Every tool is free to use with no account, trial or paywall. The sites may show ads to help cover hosting costs.
- Is my data stored or sent anywhere?
- The numbers, names and lists you type are processed in your browser and are not sent to our servers. Standard hosting and advertising services may collect ordinary visit information, as described in our privacy policy.
- How accurate are the calculators?
- They apply standard formulas and the published figures described above, but they are estimates. Rounding, local rules and details specific to your situation can make real results differ, so treat them as a starting point.
- Is the Secret Santa draw fair?
- Yes. The draw uses your browser’s cryptographic random number generator and respects the exclusions you set. It runs on your device, so nobody else sees the pairings.
- Do the tools work on a phone?
- Yes. The pages are built to load quickly and fit small screens, and they work in a modern browser without installing anything.
- How do I report a mistake or suggest a tool?
- Use the contact page or email contact@signalsop.com. Corrections to figures are especially welcome.
About these tools
New tools are added over time. Have an idea for a tool you would use? Tell us, or read more about SignalsOp.