FeeGauge

A fifth OfferStack calculator that turns "is this annual fee still worth it" into a month-by-month breakeven line, instead of a single yes-or-no guess.

Problem

OfferStack ships four locked calculators — SUB Value, Portal Stack, Travel Redemption, Utilization Helper — but none of them answer the question that actually triggers a renewal decision: has this year's $795 or $895 fee already paid for itself in credits you used? Right now a cardholder adds up scattered statement credits by hand, or takes a standalone tool like StackEasy's or FeeWorth's word for it on a site that has never seen their wallet.

Target user

Primary: the Active Optimizer from STRATEGY.md §2, staring at a renewal date on a Sapphire Reserve or Amex Platinum and deciding whether to keep paying, downgrade, or call for a retention offer. Secondary: the Aspiring Optimizer, who just took on their first premium card and wants a plain-math check before the fear-of-mistakes moment STRATEGY.md names as their core pain point.

MVP scope

• New /tools/fee-breakeven page: enter a card's annual fee plus the dollar value of each credit actually used, get a running total against the fee and a "Show math" audit panel, matching the pattern already shipped on the four locked calculators.
• Reuse the locked assumptions in VALUATION_FORMULA_SPEC.md unchanged — G4's 2.0% opportunity-cost default and G5's annual_fee/12 monthly proration — to plot a month-by-month breakeven line instead of one static verdict.
• A starter library of default credit line-items for the catalog's premium cards (Sapphire Reserve, Amex Platinum, Amex Gold), pulled from credit_cards/card_credits, so the form opens pre-filled instead of blank.
• A baseline comparison against a flat 2% no-fee card, so the output reads as an actual A/B instead of just "you spent less than the fee."
• Free tier: public single-card version, generic default credit values, no auth. Pro: wallet-aware mode that runs the calc against every card a signed-in user actually holds.

Monetization

none (internal tool) — feeds OfferStack's existing freemium model. PROJECT_REQUIREMENTS.md §4.10 already names "annual fee breakeven over time" as a planned Pro-tier calculator; this MVP is the free public version that becomes the SEO hook, with the wallet-aware multi-card mode sitting behind the existing $5–8/mo Pro tier from STRATEGY.md §5.

Why now

Chase and Amex pushed their flagship fees to $795 and $895 over the past year, and a wave of standalone breakeven calculators — CalcScope, My Credit Signal, StackEasy, PlatMath, FeeWorth — has shown up in 2026 to answer exactly this question. StackEasy's August 31, 2026 analysis frames it around a blunt stat: 68% of the cards it tracks charge no annual fee at all, and the ones that do only make sense for specific spending profiles. Meanwhile retention offers, the usual fallback, are getting harder to land — Upgraded Points' August 17, 2026 guide notes issuers have tightened up after years of people gaming the ask. OfferStack calls itself the math-first alternative to blog-post advice, but on this specific renewal-season question it currently has nothing to offer while five point-solution competitors do.

Risks & open questions

• Demand-side: the standalone competitors already do this for free with no login. OfferStack has to win on being wallet-integrated and transparent about its formula, not on being first to market.
• Build-side: card_credits currently stores a text description per credit, not a structured dollar value — this needs a schema addition before the pre-filled defaults are buildable as specced.
• Trust risk: a default credit value that's too generous for an average user quietly undercuts the math-first positioning STRATEGY.md §6.3 is built on; defaults need a visible source and an "adjust to your real usage" nudge, not a black-box number.
• Scope risk: this has to stay a pure calculator. KeepLine (idea card, unbuilt) already owns the retention-script and cohort-data territory — FeeGauge should feed a future KeepLine, not duplicate it.

Next step

Promote to a weekly prototype — build the free public /tools/fee-breakeven page against the locked VALUATION_FORMULA_SPEC assumptions, with hand-entered default credits for the top five premium cards, before scoping the card_credits schema change or the wallet-aware Pro mode.

Sources

• https://www.stackeasy.ai/blog/credit-card-annual-fee-break-even-analysis-2026 — August 31, 2026 analysis of 74 tracked cards; 68% carry no annual fee, itemized breakeven math for Sapphire Reserve, Amex Platinum, Amex Gold
• https://upgradedpoints.com/credit-cards/credit-card-retention-offers/ — updated August 17, 2026; retention offers have tightened after years of high-volume asking, raising the stakes on a rigorous keep-or-cancel calculation
• D:/AI_Agents/Projects/Mikes_AI_Lab/Repos/Private/Live_Apps/life-hacker/docs/STRATEGY.md — personas (§2 Active Optimizer, Aspiring Optimizer), Pro-tier advanced-calculator plan (§5), math-first trust positioning (§6.3)
• D:/AI_Agents/Projects/Mikes_AI_Lab/Repos/Private/Live_Apps/life-hacker/docs/PROJECT_REQUIREMENTS.md — §4.10 names "annual fee breakeven over time" as an unbuilt Pro-tier calculator; §6.2 confirms the card_credits schema gap
• D:/AI_Agents/Projects/Mikes_AI_Lab/Repos/Private/Live_Apps/life-hacker/docs/VALUATION_FORMULA_SPEC.md — G4 opportunity-cost default, G5 annual-fee proration rule, reused unchanged
• D:/AI_Agents/Projects/Mikes_AI_Lab/Repos/Private/Live_Apps/life-hacker/docs/EXECUTION_BACKLOG.md — confirmed no open LIF-### item covers a fee-breakeven calculator; the four locked calculators (LIF-035) don't include it