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Changelog

Every calculator has a version number. When the math changes, the version goes up and the change is listed here — that's the corrections policy.

Ben / Last reviewed Sep 28, 2026

Sep 27, 2026 — Version 2.0 of every calculator

A full review of all 38 calculators before they moved to calculators.debitisleft.com. Each one was rebuilt on shared, tested engines, and each fix below corrects something the earlier version got wrong or left out.

Across the site

  • Every workbook now uses live formulas, and in testing every formula is recalculated and has to match the website to within half a cent.
  • Worked examples are generated by each calculator from its own example inputs, so they can't drift from the real math.
  • Tax calculators use a tax-year table (2025 and 2026) with a source for every number, instead of one set of values for any year you typed.
  • Dates are calendar dates everywhere, so results no longer shift by a day depending on your time zone.

Loans & Debt

  • Loan Amortization (v2.0.0) — The first payment is one period after the start date, the payoff date is the date of the last payment, and month-end dates no longer spill into the next month.
  • Extra Payments (v2.0.0) — Recurring extra payments start when you say, the last payment is capped at what's owed, and you can list one-time extra payments.
  • Remaining Balance (v2.0.0) — Asks for the loan's start date and the date you want the balance for separately — the old version used one as the other.
  • Balloon Loan (v2.0.0) — Shows the balloon date and payment in the schedule, plus a yearly summary.
  • Loan Payoff (v2.0.0) — A payment too small to pay off the loan within 1,200 payments is flagged instead of silently cut off. The worked example now matches the math.
  • Refinance Comparison (v2.0.0) — Fixed workbook formulas that referenced the wrong cells. Break-even is closing costs ÷ monthly savings whether the costs are paid up front or rolled in.
  • Loan Recast (v2.0.0) — A payment bigger than required no longer pushes the balance below zero, and the recast fee is treated as a cash cost with its own payback.
  • Loan Fee Amortization (v2.0.0) — Reframed for borrowers under ASC 835-30 (interest method), with the write-off on an early payoff shown on its own.
  • Effective Interest Rate (v2.0.0) — Bullet notes include the coupon, cash interest is on the face amount, and the journal entries balance.
  • Business Debt Schedule (v2.0.0) — The last debt is no longer dropped, the current portion is principal due within 12 months, and debts are entered as a list.
  • Equipment Lease (v2.0.0) — Payments in advance accrue interest correctly and run the full term, and the liability and right-of-use asset follow ASC 842.

Assets & Depreciation

  • Straight-Line Depreciation (v2.0.0) — Adds full-month and mid-month conventions, and a final-year true-up so the asset depreciates to exactly its salvage value.
  • Asset Disposal (v2.0.0) — The journal entry balances when selling costs are more than the proceeds, and it's shown on the page.
  • MACRS Depreciation (v2.0.0) — Real property recovers its full basis, every mid-quarter table is included, and bonus depreciation and Section 179 reflect current law.
  • Asset Book Value (v2.0.0) — Disposals remove their own accumulated depreciation, and the rollforward foots.
  • Prepaid Expense (v2.0.0) — Both the monthly and daily methods work, a mid-month start no longer adds a thirteenth month, and the balance is as of the date you pick.
  • Capitalized Cost (v2.0.0) — Asset retirement obligations are recorded at present value, and items that need a judgment call are listed with the test to apply.

Business & Pricing

  • Break-Even Point (v2.0.0) — Shows the units needed for a target profit, and the margin of safety as a percent.
  • Markup and Margin (v2.0.0) — A margin of 100% or more is rejected instead of returning a $0 price.
  • Working Capital (v2.0.0) — Short-term investments count in the quick ratio, and the cash conversion cycle is included.
  • Contribution Margin (v2.0.0) — Sensitivity covers price, volume, and variable cost, and the target-profit results are shown.
  • Project Profitability (v2.0.0) — Target margin, completion percentage, and budget vs. actual by category now work.
  • Employee True Cost (v2.0.0) — Recruiting and training count once, in year one; payroll taxes use the wage bases and include bonuses; paid time off reduces productive hours.
  • Hourly Billing Rate (v2.0.0) — Utilization and write-offs are part of the rate, and the sensitivity table agrees with it.
  • Business Valuation (v2.0.0) — SDE, adjusted EBITDA, and revenue methods now actually differ, and adjustments can be negative.

Taxes

  • Estimated Tax Safe Harbor (v2.0.0) — The safe harbor is the smaller of 90% of this year's tax or 100%/110% of last year's (based on last year's AGI). A $0 prior-year tax is allowed, and the $1,000 rule is noted.
  • Quarterly Estimated Tax (v2.0.0) — Due dates follow the tax year, payments count in the quarter they're made, and the running totals follow Form 2210.
  • Self-Employment Tax (v2.0.0) — Follows Schedule SE line by line; Additional Medicare Tax follows Form 8959 and is reported separately; church employee income gets its own line; the $400 threshold applies.
  • Section 179 (v2.0.0) — Carryforwards are deducted, basis is reduced by the full amount elected, the phase-out uses all Section 179 property, and the more-than-50% business-use test applies.
  • Depreciation Recapture (v2.0.0) — Losses are allowed, Section 1250 additional depreciation is recaptured, and property held a year or less is ordinary income.
  • Installment Sale (v2.0.0) — Depreciation recapture is added to basis before the gross profit percentage, so it isn't taxed twice, and the note collects in full.

Work & Pay

  • Salary to Hourly (v2.0.0) — Works in both directions, with pay-period amounts and pay per hour actually worked.
  • Salary to Contractor Rate (v2.0.0) — The profit margin is a margin on revenue (not a markup), non-billable hours count, and employer payroll tax respects the wage base.
  • Overtime Pay (v2.0.0) — The regular rate includes a nondiscretionary bonus the way 29 CFR 778.110 requires — the old version could underpay overtime.
  • Shift Differential (v2.0.0) — Overtime can fall on any shift, and it's figured on the weighted regular rate with differentials included.
  • Retroactive Pay (v2.0.0) — Retro pay already received is no longer counted twice. Adds salaried pay, overtime at the raise × 1.5, and a withholding estimate.
  • PTO Payout (v2.0.0) — Adds salaried pay, shows only the balance field you need, and supports a payout cap in hours.
  • Job Offer Comparison (v2.0.0) — One-time costs no longer reduce every year's value, the comparison with the first job is shown, and jobs are entered as a list.

Spot something?

If a number looks wrong, tell me. The fix — and credit, if you want it — shows up here.