HP · 00041-15004
The Financial Decisions Pac turned an HP-41 into a finance machine years before most people owned a computer. Its programs cover compound interest with the familiar N, I, PV, PMT and FV, internal rate of return for up to 46 uneven cash flows, modified IRR, net present value, amortization schedules, straight-line, declining-balance and sum-of-the-years'-digits depreciation, bond pricing and yields, and days between dates. The manual we found is revision B from January 1980, so the pac was on sale by then, and HP kept revising the ROM through revision D. It's a good add-on for a 41 that does double duty, though a dedicated HP 12C does the everyday sums with fewer keystrokes.
Module check
Should come with it
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Check the contacts for corrosion carried over from a leaky calculator. The manual explains each program's inputs, so a pac without one is less useful.
Choosing modules for a 41? The HP-41C, CV and CX explainer covers memory, ports and what each model has built in.
Buying guide
We'd buy clk430gtr's Financial Decisions Pac titled works and tested at $35 delivered, or for $29 delivered take jones.sebago.lake's with the manual and overlays, which isn't titled tested but includes the book that explains each program's inputs. There are at least 12 for sale, bare modules ask $24-49 delivered, and the boxed or complete sets run $61-64. It fits every HP-41, and a 41CV or 41CX gives the IRR program room for more cash flows. Ask for a close photo into the module's open end, since corrosion from a leaky 41 can reach the contacts. The Spanish-language Paquete De Decisiones Financieras sets ask $108-138 delivered, more than twice the $48 median, so buy one only if you want the Spanish manual.
$24.49delivered
The lowest price on this pac at $24 with free shipping, from a 99.8% seller. It's the module alone with no manual and no test claim, so ask for a close photo of the contacts.
Hewlett Packard Financial I Module Pac HP 00041-14003 for 41C/41CV/41CX
$35.34est. delivered
The only pac here titled works and tested, at $35 delivered from a 100% seller, near the bottom of the band. It's the module alone, with no manual.
HP FINANCIAL 1 (HP-00041-15004) ROM MODULE FITS HP- 41C/CV/CX WORKS - TESTED
Delivered prices include shipping as eBay quoted it to a US address on Oct 15, 2026. Many sellers charge by distance, so your total may differ. eBay shows yours before you pay.
Snapshot
Checked . Some may have sold.
Delivered prices include shipping as eBay quoted it to a US address on Oct 15, 2026. Many sellers charge by distance, so your total may differ. eBay shows yours before you pay.
Used$24.49delivered
$24.49 · free shipping
Buy It Now$24.49
This seller takes offers, and many sellers accept less than the asking price.
Fine if you might miss it? Send an offer first. Someone else can still buy it while you wait for a reply.
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Good buy
Module only, 00041-14003 label in the photo. No test claim.
Seller: sshebalee1982
99.8% positive
Used$35.34est. delivered
$30.00 + $5.34 shipping
Buy It Now$30.00
Good buy
Titled works and tested. Module only.
Seller: clk430gtr
100% positive
Used$28.76est. delivered
$19.41 + $9.35 shipping
Buy It Now$19.41
Our take
With manual and overlays, both in the photo. No test claim.
Seller: jones.sebago.lake
99.8% positive
For parts$34.17est. delivered
$27.49 + $6.68 shipping
Buy It Now$27.49
This seller takes offers, and many sellers accept less than the asking price.
Fine if you might miss it? Send an offer first. Someone else can still buy it while you wait for a reply.
Want it for sure? Use Buy It Now.
Our take
Module only, titled untested.
Seller: mb71994
100% positive
Used$61.26est. delivered
$44.41 + $16.85 shipping
Buy It Now$44.41
Our take
Titled complete in box; the photo shows the pac box.
Seller: jones.sebago.lake
99.8% positive
Used$63.99est. delivered
$60.00 + $3.99 shipping
Buy It Now$60.00
This seller takes offers, and many sellers accept less than the asking price.
Fine if you might miss it? Send an offer first. Someone else can still buy it while you wait for a reply.
Want it for sure? Use Buy It Now.
Our take
Module, overlay and manual in the photo. No test claim.
Seller: leo.merchant
100% positive
Used$49.40est. delivered
$35.08 + $14.32 shipping
Buy It Now$35.08
Check the seller
Module only. Seller feedback 95.8%, ships from Canada.
Seller: randomflavours
95.8% positive
Used$137.82est. delivered
$125.00 + $12.82 shipping
Buy It Now$125.00
This seller takes offers, and many sellers accept less than the asking price.
Fine if you might miss it? Send an offer first. Someone else can still buy it while you wait for a reply.
Want it for sure? Use Buy It Now.
Priced high
Spanish-language pac. About 2.9 times the median.
Seller: oxido70
100% positive
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