⚖ Lawyers
Judgment and pre-judgment interest, accrual on overdue installments, variable statutory rates, matter-numbered case files, calendar with deadlines, and Sage Timeslips bill & slip import to bring your archive online.
Fourteen powerful calculators plus case management, calendar, document vault and Sage Timeslips import — everything lawyers, accountants and finance teams need to run the numbers and the file. Save every calculation, tie it to a client or matter, and export with your letterhead in one click.
No credit card required • Free plan forever • Upgrade any time from $4.99/mo
Judgment and pre-judgment interest, accrual on overdue installments, variable statutory rates, matter-numbered case files, calendar with deadlines, and Sage Timeslips bill & slip import to bring your archive online.
Loan amortization, CPI indexation, present-value and IRR calculations, multi-currency, full audit trail — every input and result saved and exportable.
Team sharing up to 10 users, per-client calculation history, bulk CSV import, tags and document sharing, session revocation and admin controls.
Every calculator saves inputs, results and a detail table you can export to CSV or branded PDF.
Straight-line interest between two dates with optional annual capitalization and a per-year interest table.
Full amortization schedules for mortgages, loans and leases. Solve for payment, rate, term or principal.
Simple or compound interest with fixed or variable rates and four day-count conventions.
Track overdue payments and compute accruing interest on arrears automatically.
Lump-sum and annuity PV/FV. Solve for any variable across any compounding frequency.
Effective annual return or IRR for irregular cash flows.
Convert between nominal and effective rates across any compounding frequency.
Adjust amounts for inflation or a custom index rate with year-by-year breakdown.
Convert payments between frequencies using PV equivalence or simple ratio.
Tax on net or extract tax from gross. Multi-layer tax with optional tax-on-tax.
Days between dates using multiple conventions. Add or subtract periods precisely.
Full payment schedules across monthly, biweekly, weekly, quarterly, semiannual and annual frequencies, with extra-payment what-ifs.
Compare avalanche vs. snowball strategies across up to ten debts. See payoff date, total interest and months saved versus a minimums-only baseline.
Estimated quarterly tax payments for self-employed and 1099 earners using current-year IRS brackets, with safe-harbor target calculations.
Bring your historical bills and slips out of the desktop and into a searchable, shareable cloud archive. CSV import. No add-on. No re-keying.
Upload a CSV from Reports → Bills → Bill List. Search by bill #, client, matter or status. KPIs for total billed, paid and outstanding refresh as you filter.
Upload time and expense slips from Reports → Slip → Slip Listing. Filter by timekeeper, task, client, billed status or date range. Up to 5,000 rows per file.
Stock Timeslips reports work without remapping — common column names ("Bill #", "Invoice Number", "Time Spent", "Value", "TK") are auto-detected.
Every import shows a row-by-row preview with duplicates flagged in yellow and errors in red. Tick "Replace existing" to overwrite, or skip dupes. Nothing is written until you confirm.
Don't have a Timeslips export handy? Download the bill or slip CSV template from the import dialog, fill it in and upload. Same dedup and preview rules apply.
Imported bills and slips can be filtered by client and matter, sit alongside your saved calculations, and can be referenced from your case file.
Every client can hold multiple cases. Link calculations, bills, slips and documents to a specific matter so the full file opens with one click.
Hearings, statute-of-limitation dates, filing deadlines and per-matter events on one shared calendar — colour-coded by case.
One search box across clients, cases, calculations, bills, slips and documents. Find anything by name, matter number, bill number or keyword.
Keep every client's contact details in one place. Every saved calculation is linked to a client profile so their full history is one click away.
Tag calculations by matter, year or status and filter the dashboard instantly. Bookmark important calculations to pin them to the top — always one click away.
Attach free-text notes to any saved calculation — context, assumptions or internal memos — right alongside the numbers.
Upload contracts, statements and supporting files. Share with a password-protected expiring link, track every download, and recover from a 30-day trash.
Send the branded PDF directly to your client with a one-line cover note — straight from the calculation page.
Your company name, address, phone, email and logo at the top of every exported PDF. Looks like it came from your firm, not ours.
Invite up to 10 team members on the Pro plan. Shared client pool, recent team activity feed, and per-device session revocation.
Interest Calculator Pro is a Progressive Web App — install it on Mac, Windows, iOS or Android for a one-tap launch and offline-friendly experience.
Email, Google or passwordless 6-digit code sign-in, math CAPTCHA after failed attempts, revocable active sessions, and a full account activity log.
Start free. Upgrade when you need more saved calculations or a team.
$49.90 / year (2 months free)
$99.90 / year (2 months free)
A professional SaaS that bundles fourteen interest, loan and finance calculators with case management, calendar, document vault and Sage Timeslips import (bills and slips) into one cloud workspace. Built for lawyers computing judgment and pre-judgment interest, accountants running amortization schedules, and finance teams that need reliable, auditable calculations with letterhead-branded PDF exports.
Simple Interest, Recurring Payments (Amortization), Interest Between Dates, Accrual by Installment, Present Value, Annual Rate of Return, Nominal/Effective Rate Converter, Amount Indexation, Payment/Indexation Converter, Sales Tax, Date Calculations, Loan Amortization, Debt Payoff Planner and Quarterly Tax Planner.
Yes. The Free plan includes three core calculators — Simple Interest, Interest Between Dates, and Sales Tax — plus up to 5 saved calculations and a 5-client directory. Basic ($4.99/mo) unlocks all 14 calculators, unlimited saved calculations, letterhead PDF export and Sage Timeslips bill & slip import. Pro ($9.99/mo) adds case management, calendar, team sharing for up to 10 users, bulk CSV import and variable-rate schedules.
Yes. Interest Calculator Pro accepts CSV exports from Sage Timeslips (Premium v30 and earlier). The Bills page imports historical invoices with totals, payments, balances and statuses; the Slips page imports time and expense slips with timekeeper, task, hours, rate and billed status. Both use a fuzzy column-name match so most stock Timeslips reports work without remapping. Each import previews the rows, flags duplicates and lets you confirm before saving anything.
Yes. Each client can have multiple cases (matters). Calculations, bills, slips and documents can be linked to a specific case so the full file is one click away. Cases also appear on the Calendar with their hearings, deadlines and statute-of-limitations dates.
Yes. Every saved calculation can be shared through a read-only public link or emailed directly to the linked client as a branded PDF with your letterhead — company name, address, phone, email and logo all on top.
Actual/365, Actual/360, Actual/Actual and 30/360. You can set a per-account default in Settings and override it on each individual calculation.
Yes. Paid plans include CSV bulk-import for calculations across every calculator type, plus a separate CSV import for your client directory. Templates with sample rows are provided on each import page.
Accounts are protected with email or Google sign-in, a math CAPTCHA after failed login attempts, and a Signed-in Devices page that lets you revoke any active session. Passwords are hashed with bcrypt and sessions are rotated on login.
Yes. Subscriptions are billed monthly or annually through Stripe or PayPal. You can cancel at any time from the Billing page; your plan remains active until the end of the current billing period.
Question about a calculator, a pricing plan or an account? Send us a note and we'll get back to you within one business day.
Prefer email? Write us at [email protected].
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