Tankfern by CyberMaxFor heating-oil and propane dealers · HVAC service firms · facility energy managers
Fill every tank before it runs dry.
Tankfern turns live NOAA heating degree days and each tank's K-factor into gallons used, % full today and a deliver-by date, then sorts your customers into this week, next week and later, ready to print as a route sheet. Free for up to 10 customer tanks. Pro $29/month.
- No sign-up
- Your account list stays in your browser
- Live NOAA degree days
- Weekly EIA oil and propane prices
Try it free with sample tanks Get Pro · $29/month
14-day fix-or-refund if it doesn't work as described · Cancel any time · Secure checkout by Stripe
Your delivery planner
0 of 10 free tanksPlanning estimates only — always check the tank gauge. Not a safety device.
Station: none yet
Loading degree days…
| Account | Fuel · size | K-factor | Now | Deliver by | Runs out | List | Actions |
|---|
No tanks yet. Add your first customer tank below, or .
Delivery list · route sheet
Residential fuel prices this week
Loading EIA prices…
Prices: U.S. Energy Information Administration, weekly residential survey. The survey runs October to March; out of season you see the last survey week.
How the forecast works
1 · Gallons used since the last fill
We assume the last delivery filled the tank to its usable level (say 90% for oil, 80% for propane). Since then it has burned HDD since the fill ÷ K + fixed load × days. HDD are heating degree days from your NOAA station at the account's base temperature (default 65 °F). The fixed load is hot water or process use in gallons a day.
2 · K-factor
K is degree days per gallon: a big K means a frugal house. Type it in, or let Pro learn it: between two fill-ups, K = HDD between deliveries ÷ (gallons delivered − fixed load × days), averaged over the last 3 usable fills. Summer intervals with no heating use are skipped.
3 · Run-out and deliver-by dates
From today we walk forward day by day using projected HDD: by default the same calendar days last year at the station (real weather for this season, not a flat guess), or the station's average of the last 7 days, or your own number. "Deliver by" is the day the tank reaches your reorder level; "runs out" is the day it reaches empty.
Real sample output
Six fictional accounts, Newark Liberty Intl Airport (EWR) degree days from NOAA ACIS, computed by this page on 9 Oct 2026. Two K-factors were learned from last winter's fill-ups.
| Account | Fuel · tank | K-factor | Now | Deliver by | Runs out | Fill (gal) | List |
|---|---|---|---|---|---|---|---|
| A-1006 Elm St office | Oil · 330 | 7.8 | 17% | Oct 9 | Nov 14 | 243 | This week |
| A-1004 Riverside garage | Oil · 275 | 4.6 | 17% | Oct 9 | Oct 30 | 201 | This week |
| A-1002 Cedar Lane diner | Propane · 1000 | 9.5 | 36% | Oct 21 | Dec 6 | 505 | Next week |
| A-1005 Pine Ridge farmhouse | Propane · 500 | 3.37 learned | 49% | Nov 4 | Nov 28 | 254 | Later |
| A-1003 Birch Court, unit 4 | Oil · 275 | 6.01 learned | 47% | Nov 6 | Nov 25 | 180 | Later |
| A-1001 Hillside Church hall | Oil · 550 | 4.2 | 80% | Dec 19 | Jan 6 | 362 | Later |
Pricing
Free: up to 10 customer tanks, live degree days for 1 station, forecasts and the route sheet. No sign-up, no card. Pro removes the limit.
Free
- Up to 10 customer tanks
- Live degree days for 1 station
- Forecasts: % full, run-out, deliver-by
- Delivery list and route sheet
- Weekly EIA fuel prices
Pro · yearly
$24.17 a month, billed once a year
- Unlimited customer tanks
- Several degree-day stations
- CSV import and export (accounts, deliveries)
- K-factors learned from delivery history
- Price alerts
- Route sheets with totals
Secure card checkout by Stripe; your licence key appears right after payment. 14-day fix-or-refund if it doesn't work as described (terms). Cancel any time.
How it compares (prices on each vendor's or reviewer's page, checked 9 Oct 2026)
| Product | What it is | Price |
|---|---|---|
| Tankfern | Degree-day forecasts, K-factors, delivery list and route sheet | Free up to 10 tanks · Pro $29/month or $290/year · $449 lifetime |
| Degree Days Online | Degree-day delivery software for fuel dealers | $119.95/month "for most companies" (vendor page); Basic from $79.95/month (TrustRadius) |
| DegreeDays.net API | Degree-day data only (you build the planner) | From $9/month for 1 location, $39/month for 10 locations |
| Droplet Fuel | Full back office: dispatch, billing, delivery | Price on request |
FAQ
Why not Degree Days Online or a full dispatch system like Droplet Fuel?
They are complete back-office platforms: dispatch, billing, trucks, payments. If you need all that, they are the right call. Tankfern is the lightweight planner for dealers who don't: degree-day forecasts, K-factors and a route sheet in a browser tab, free for up to 10 tanks and $29 a month for unlimited, against $79.95 to $119.95 a month for Degree Days Online (checked 9 Oct 2026).
Why not just buy degree-day data from DegreeDays.net?
Their API is good data from $9 a month for one location, but it is data only: you still build and maintain the K-factor spreadsheet. Tankfern uses NOAA's free degree days and does the forecasting, the learning and the sorting for you.
Where is my data stored?
In your browser only, on this device. Our server never receives customer names, tanks or deliveries; it only passes public NOAA degree days and EIA prices through a cache. Use CSV export (Pro) to back up or move your list. Clearing your browser data clears the list.
Is this advice? Is it a safety device?
No. Tankfern gives planning estimates only — always check the tank gauge. It is not a safety device, and it is an information tool, not engineering, safety or financial advice. Weather can beat any projection; keep a margin with your reorder level.
Where do the numbers come from?
Daily heating degree days come from NOAA's Regional Climate Centers (the Applied Climate Information System), for the station you pick, at each account's base temperature. Prices are the U.S. Energy Information Administration's weekly residential heating oil and propane survey. Both are refreshed through a cache every few hours.
What happens when live data is down?
Tankfern says so and keeps working: it uses the degree days it already has, and you can type an HDD-per-day figure to project with. The sample runs on degree days recorded from NOAA on 9 Oct 2026.
What exactly is free?
Up to 10 customer tanks, live degree days for 1 station, every forecast and the delivery list with a printable route sheet. Pro adds unlimited tanks, several stations, CSV import and export, learned K-factors, price alerts and route-sheet totals.
How do I cancel?
Open Manage subscription with your key: Stripe's billing portal lets you cancel or change your card. Lifetime keys never renew.