THE QUICK ANSWER
This tool uses only your date,price CSV. It sorts observations and draws connecting lines; it does not fetch live prices, estimate missing dates or predict a future sale.
01
Paste at least two dated observations
Use the header date,price in that order and supply 2 to 1,000 rows. Each date must be a real YYYY-MM-DD date between 1900 and 2200, with exactly one observation per date. Enter prices as non-negative numbers with a decimal point and no currency symbols or thousands separators.
Enter a three-letter currency or price-unit label separately. Keep every row on the same basis: the same item variant, price type and currency. The label does not convert values or establish that a number is a completed sale.
Turn a supplied series into a labelled chart
CSV
Enter date,price rows and one unit label.
Sorted points
The tool orders the dates and keeps recorded values.
SVG
Download the chart and retain the original data context.
Original workflow for reader-supplied observations; no provider price feed is implied.
Original explanation · not an account screenshotTry it with your own details.
This tool keeps your input in this page. It does not upload it, add it to the address or save it. Downloads happen only when you choose them. Reset the form when you finish.
02
Read the range and the chronological change
The tool sorts the dates before drawing. Its range is the lowest and highest supplied price; first-to-last change compares the earliest date’s price with the latest date’s price. If the first price is zero, the percentage change is undefined and is reported that way.
A rising line describes your selected observations. An asking-price series, a sale-price series and a mixed series support different interpretations. Keep the original source and observation method with your CSV rather than letting the chart title imply a marketplace feed.
| CSV observations | 2026-10-20,10.00; 2026-10-22,11.50; 2026-10-26,10.75 — one date,price pair per line. |
|---|---|
| Range | 10.00–11.50 in the entered unit. |
| First-to-last change | 7.50% from the earliest supplied price to the latest. |
| Observation gaps | Two intervals longer than one day; this is not a count of two missing dates. |
03
A connecting line is not a missing observation
The result counts consecutive observation intervals longer than one day. It does not insert values into those gaps or treat missing dates as zero. In the example, the gaps after October 20 and October 22 have different lengths.
Use the visible points and their date/price labels to distinguish recorded values from the line between them. If you need an intraday chart, combine or select the intended daily observations yourself; duplicate dates are rejected by this form.
What the line and the gap count mean
Recorded point
A price you supplied for that exact date.
Connecting line
A visual connection between supplied points.
Gap longer than one day
One missing-observation interval, not an inserted estimate or a count of missing dates.
Original reading guide for this chart’s exact gap behaviour.
Original explanation · not an account screenshot04
Download the chart with its data context
Choose supplied-price-history.svg to save the plotted chart. The tool supplies a chart download, not a fresh price feed or a normalized CSV export. Keep your original CSV and source notes alongside the image.
The tool does not save or upload your input. Editing a field removes the previous result and download link, so draw the updated series again before exporting. Use Reset this form when finished. A file you already chose to download remains under your control.
BEFORE YOU CONTINUE
Quick checklist
- Use date,price and at least two distinct dates.
- Keep one item variant, price basis and currency.
- Read first-to-last change in chronological order.
- Treat gaps as absent observations, not estimated prices.
- Save the source CSV with any exported SVG.
Official sources
Tool behaviour was checked against StrikePot’s form and browser implementation on 26 October 2026 (America/Toronto). The external references below explain the relevant formats and source records.
- RFC Editor — RFC 4180: CSV fields and records · reviewed
- MDN — Date.parse: interpreting date strings · reviewed
Implementation inspected: price-history form, gtCSV, gtHistory, SVG chart creation and SVG download handler. Sorting, one-observation-per-date validation, first-zero percentage handling and gap count are exact code behaviour. No marketplace, live quote, historical-price API, interpolation, currency conversion or forecast was used. All numerical examples are invented observations.
