PFTools — The Finometer

Total Interest Accumulated

$0.0000000000

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0 sources

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Name

Principal ($)

Rate (%)

Compounds

Type

Controls

💸 Dollar Debasement

CPI Inflation Rate (%)

Feb 2026 · BLS

Your blended savings rate —

CPI inflation rate 2.40%

Real return —

Purchasing power lost per second

—

on your total savings balance

Net gain/loss per second

—

Interest Sources

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Source	Principal	Rate	Compounds	Interest	Type

📊

No sources yet. Add a savings account or loan to get started.

How to Use the Finometer

The Finometer tracks compound interest to the second across multiple financial sources — savings accounts, loans, credit cards, mortgages, anything with an interest rate. Here's a complete guide to every feature.

① Adding Sources

Name — Give your source a descriptive label, e.g. "Marcus HYSA", "Chase Sapphire", "30yr Mortgage". You can add as many sources as you like.
Principal — Enter the current balance of the account or the outstanding debt amount in dollars.
Rate (%) — Enter the annual interest rate as a percentage. For example, enter 4.5 for 4.5% APY. Check your bank's current rate — it may have changed recently.
Compounds — How often interest is calculated. Daily is the most accurate for most savings accounts and credit cards. Use Monthly or Quarterly for some bonds and CDs, and Yearly for simple loan estimates.
Type — Choose ↑ Saving if this source earns interest for you (savings accounts, CDs, bonds). Choose ↓ Spending if this source costs you interest (credit cards, mortgages, auto loans). This determines whether the interest adds to or subtracts from your total.
Add Source — Click the green button to add the source to the table. It will appear with $0 interest accumulated and begin ticking the moment you hit Start.

② Running the Calculator

Start — Begins the real-time ticker. Interest accumulates every second based on each source's principal, rate, and compounding frequency. The status badge in the hero area turns green and reads "LIVE".
Stop — Pauses accumulation. Your progress is saved automatically to your browser so it persists if you close the tab. Click Start again to resume.
Fast Forward +30d — Instantly calculates and adds 30 days of compound interest to all sources. Useful for projecting a month ahead without waiting.
Fast Forward +1yr — Same as above but for a full year. Great for long-term projections on mortgages or savings goals.
Clear Interest — Resets all accumulated interest back to zero without removing your sources. Use this to start a fresh accumulation period.
Reset All — Removes all sources entirely and clears all data. Requires confirmation and cannot be undone.

③ The Dashboard

The Dashboard is your at-a-glance view. It shows the hero interest total, the Dollar Debasement panel, and a collapsible What If section — no clutter.

Total Interest — The large number at the top updates every second while running. Green means net positive (savings outpacing debt), red means net negative.
₿ Sats toggle — Click the ₿ sats button next to the total to convert your accumulated interest into Bitcoin satoshis in real time. The live BTC price is fetched automatically from Coinbase. You can override the price manually if you want to model a different BTC price. The number switches to yellow and displays in sats (or BTC if large enough). Click again to return to dollars.
What If Scenarios — Collapsed by default to keep the dashboard clean. Click the header to expand. Three scenarios let you explore: how long it takes to earn back a spending amount, what pandemic-era rates (0.5%) would mean for your interest, and what 1980s-era rates (18.9%) would mean. None of these affect your live data.
Interest Sources table — Visible on the dashboard on desktop, and accessible via the Sources tab on mobile. Shows each source with its accumulated interest ticking live.

④ Managing Sources

Edit a source — Click the ✏️ pencil icon on any row to edit the source name, principal, rate, and type inline. Click Save when done. Only one row can be edited at a time.
Delete a source — Click the ✕ button on any row to permanently remove that source.
Hide Principals — Toggle the switch in the table header to replace all principal amounts with bullet characters. Useful when sharing your screen.

⑤ Saving & Loading Your Data

Auto-save — Your sources and accumulated interest are automatically saved to your browser's local storage and restored on your next visit. Note: clearing your browser data will erase this.
Export — Downloads a .json file with all your sources and accumulated interest, named with today's date. Use this to back up your data or transfer it to another device.
Import — Loads a previously exported .json file, replacing your current sources after a confirmation prompt. Accumulated interest is preserved exactly as exported.

⑥ Dollar Debasement

This panel answers the most important question in personal finance: is my money growing faster than it's losing value?

CPI vs M2 toggle — Choose your debasement benchmark. CPI uses the official Consumer Price Index published by the Bureau of Labor Statistics — the standard measure of inflation. M2 uses the annual growth rate of the U.S. money supply published by the Federal Reserve — a measure of how fast new money is being created, which many consider a more direct measure of dollar debasement. Both are pre-populated with current figures and fully editable.
Blended savings rate — Your weighted average interest rate across all Saving sources, weighted by principal. A $50,000 account counts proportionally more than a $5,000 account.
Real return — Your blended rate minus the debasement rate. Positive means your money is genuinely growing in purchasing power. Negative means debasement is outpacing your interest — even if your balance is going up in nominal terms.
Purchasing power lost per second — How much value your total savings balance loses every second due to debasement alone, regardless of interest earned.
Net gain/loss per second — Interest earned per second minus purchasing power lost per second. This is your true real-time financial progress.
Verdict badge — A clear ✓ BEATING INFLATION or ✗ LOSING TO INFLATION indicator that updates instantly as you change the rate or toggle between CPI and M2.

⑦ Use with Tidbyt

Tidbyt is a small retro LED display that can show live data on your desk. The Finometer has a companion Tidbyt app that displays your interest ticker in real time.

Click the Use with Tidbyt button in the Controls panel.
The modal calculates blended values for your Savings and Debt buckets — a weighted average rate and total balance for each.
Use the Copy buttons to copy each value, then paste them into the Tidbyt Finometer app settings on your phone.
Because Tidbyt's settings UI is simpler than the web app, multiple accounts are consolidated into two buckets using weighted averages — so your display stays clean and accurate.

⑧ Mobile Navigation

On mobile, the app uses a three-tab bottom navigation bar to keep things clean and scroll-free:

Dashboard — Your default view. Shows the hero total, Debasement panel, and collapsed What If section.
Sources — The add-source form and the Interest Sources table. Add, edit, and manage your accounts here.
Controls — Start, Stop, Fast Forward, Clear, Reset, Export, Import, and the Tidbyt button.

⑨ Light & Dark Mode

Click the ☀️ / 🌙 icon in the top navigation bar to toggle between dark and light themes. Your preference is saved and restored on your next visit.

PFTOOLS · BUY TO COVER, LLC

Terms of Use

Version 1.2 · Effective March 29, 2026 · Governed by the laws of New Jersey, USA

Contents

01. Introduction & Acceptance 02. Description of the Service 03. No Financial Advice 04. Accuracy & Calculations 05. Third-Party Data & Services 06. Data Privacy & Local Storage 07. Intellectual Property 08. User Conduct 09. Disclaimer of Warranties 10. Limitation of Liability 11. Indemnification 12. Modifications to the Service 13. Amendments to These Terms 14. Dispute Resolution & Arbitration 15. Governing Law & Jurisdiction 16. Severability 17. Entire Agreement 18. Contact

01Introduction & Acceptance

Welcome to PFTools (the "Service"), a suite of free, browser-based personal finance tools available at pftools.io, including the Finometer (real-time interest and inflation calculator) and PBD (Personal Bitcoin Dominance). The Service is owned and operated by Buy to Cover, LLC, a New Jersey limited liability company ("we," "us," or "our").

By accessing or using the Service in any way — including visiting the website, using the Finometer calculator, exporting or importing data, or using the companion Tidbyt integration — you ("you" or "User") agree to be legally bound by these Terms of Use ("Terms"). If you do not agree to all of these Terms, you must immediately cease using the Service.

Users must be of legal age to form a binding contract in their jurisdiction, or must have the verified consent of a parent or legal guardian, to use the Service. These Terms constitute a legal agreement between you and us. Please read them carefully.

02Description of the Service

PFTools is a suite of free, client-side personal finance tools. All tools run entirely in your browser with no server-side data processing. Current tools include:

The Finometer — a real-time compound interest calculator that allows users to model multiple financial sources including savings accounts, credit cards, mortgages, and loans. Features include:

Real-time compound interest accumulation across multiple user-defined sources.
Fast-forward projections (30 days, 1 year) for planning purposes.
Dollar debasement analysis using CPI and M2 benchmarks sourced from publicly available government data.
Optional display of accumulated interest denominated in Bitcoin satoshis, using a live price feed from Coinbase.
"What If" scenario modeling for illustrative purposes.
Export and import of user data as JSON files stored locally on the user's device.
An optional companion integration with Tidbyt LED display hardware.

PBD (Personal Bitcoin Dominance) — a tool for visualizing your Bitcoin holdings relative to the total supply and global holder distribution. Features include:

Spot BTC and Bitcoin ETF (IBIT, FBTC, ARKB, custom) holdings input with BTC-equivalent conversion.
Dominance calculation against the 21M hard cap, circulating supply, or adjusted supply.
Peer comparison against estimated global holder distribution tiers.
Portfolio composition analysis across Bitcoin and other asset classes.
Live BTC price feed from Coinbase for USD value calculations.

The Service is provided free of charge. We accept voluntary Monero (XMR) donations but do not charge fees, require registration, or collect payment information of any kind.

03No Financial Advice

Important: Nothing on this website or produced by the Finometer or PBD constitutes financial, investment, tax, legal, or professional advice of any kind.

The Service is provided strictly for informational and educational purposes only. All calculations, projections, scenarios, benchmarks, and outputs are illustrative models based solely on user-provided inputs and publicly available data. They are not predictions, guarantees, or recommendations.

We strongly encourage you to consult a qualified and licensed financial professional before making any financial decisions. We are not registered as a financial advisor, broker-dealer, investment advisor, or any similar professional capacity in any jurisdiction.

04Accuracy & Calculations

We make reasonable efforts to ensure that the mathematical formulas underlying the Finometer are accurate. However, we make no representations, warranties, or guarantees that calculations are accurate, complete, error-free, consistent with financial institutions, suitable for any particular purpose, or compliant with regulations in your jurisdiction.

Results may differ from actual financial outcomes due to variable rates, fees, penalties, APR vs APY differences, rounding, or interruptions in third-party data feeds. Your use of and reliance on the Service is entirely at your own risk. Always verify important figures against official statements from your financial institution.

05Third-Party Data & Services

The Service integrates with several third-party data sources. We do not control these third parties and make no representations about the accuracy, availability, or reliability of their data.

Coinbase: Live BTC price data is fetched from the Coinbase public API for informational purposes only — not investment advice.
U.S. Bureau of Labor Statistics (CPI): CPI figures are sourced from BLS public data releases and updated periodically.
Federal Reserve (M2): M2 growth rate figures are sourced from Federal Reserve public data as an alternative debasement benchmark.
Tidbyt: We are not affiliated with Tidbyt, Inc. Use of Tidbyt is subject to their own terms and privacy policy.

External links are provided for convenience only. We do not endorse or guarantee any third-party content, products, or services.

06Data Privacy & Local Storage

The Finometer is designed with a privacy-first architecture. We do not require registration or collect personal information. Your financial data is stored exclusively in your browser's local storage and is never transmitted to our servers. We do not use cookies, tracking pixels, or third-party analytics. Export files are saved directly to your device — we retain no copy. Clearing your browser's local storage will permanently erase all saved data. When the BTC price feature is enabled, a request is made to Coinbase's public API from your browser, which may expose your IP address to Coinbase subject to their privacy policy.

07Intellectual Property

The Service, including its source code, design, interface, text, graphics, logos, and the "PFTools" and "Finometer" names, are the intellectual property of Buy to Cover, LLC. You are granted a limited, non-exclusive, non-transferable, revocable license for personal, non-commercial use only. You may not copy, distribute, modify, reverse engineer, or commercially exploit any portion of the Service without express written permission.

08User Conduct

By using the Service, you agree not to use it for unlawful purposes; attempt to probe or exploit vulnerabilities; gain unauthorized access to any systems; transmit malicious code; use automated means to scrape or monitor the Service; interfere with its performance or availability; or engage in fraudulent or deceptive conduct.

09Disclaimer of Warranties

The Service is provided on an "as is" and "as available" basis, without any warranties of any kind, express or implied.

To the fullest extent permitted by applicable law, we expressly disclaim all warranties including implied warranties of merchantability, fitness for a particular purpose, and non-infringement; that the Service will be uninterrupted, error-free, or secure; and that any information provided is accurate, complete, or reliable.

10Limitation of Liability

To the fullest extent permitted by applicable law, we shall not be liable for any indirect, incidental, special, consequential, or punitive damages; loss of profits, revenue, or data; financial losses from reliance on the Service; or damages from third-party conduct or service interruptions. Because the Service is offered free of charge, our maximum aggregate liability shall not exceed USD $0.00.

11Indemnification

You agree to defend, indemnify, and hold harmless us and our contributors from any claims, damages, losses, liabilities, costs, and expenses (including attorneys' fees) arising from your use of the Service, your breach of these Terms, your violation of any third-party right, or any claim that your use caused damage to a third party.

12Modifications to the Service

We reserve the right at any time and without notice to modify, update, or discontinue any feature or the Service in its entirety. We shall not be liable for any modification, suspension, or discontinuation. We encourage you to export your data regularly using the built-in Export feature.

13Amendments to These Terms

We reserve the right to update these Terms at any time. Changes will be reflected in an updated version number and effective date. Your continued use of the Service following any changes constitutes your acceptance of the updated Terms.

14Dispute Resolution & Arbitration

Binding Arbitration. Any dispute arising out of or relating to these Terms or the Service shall be resolved by binding arbitration in New Jersey, USA, before a single arbitrator administered by the AAA pursuant to its Consumer Arbitration Rules.

Class Action Waiver. Disputes shall be conducted only on an individual basis — not in any class, consolidated, or representative action.

Jury Trial Waiver. If a claim proceeds in court, both parties waive any right to a jury trial.

Small Claims Exception. Either party may seek relief in small claims court for disputes within that court's jurisdiction. The Federal Arbitration Act governs this clause.

15Governing Law & Jurisdiction

These Terms are governed by the laws of the State of New Jersey, USA, without regard to conflict-of-law principles. Buy to Cover, LLC is incorporated and operates in New Jersey. To the extent any dispute proceeds in court, you consent to the exclusive jurisdiction of state and federal courts located in New Jersey.

16Severability

If any provision of these Terms is found to be unlawful or unenforceable, that provision shall be deemed severable and shall not affect the validity or enforceability of the remaining provisions.

17Entire Agreement

These Terms constitute the entire agreement between you and us regarding your use of the Service and supersede all prior agreements, representations, and understandings relating to the same subject matter.

18Contact

If you have questions, concerns, or feedback about these Terms or the Service, please reach out via the contact information available on pftools.io. These Terms do not create any agency, partnership, joint venture, employment, or franchise relationship between you and us.