Cronwise — Cron Schedules, Overlap & Coverage

Cronwise — Cron Schedules, Overlap & Coverage — a premium, 100% offline digital tool by Aceplore. Runs entirely in your browser: no accounts, no subscriptions, your data never leaves your device.

A private, offline desk for scheduled work — every expression expanded field by field, the next fires computed by search rather than by adding an interval, the jobs that outrun their own schedule, and the pairs that collide by the minute. 33 tools in one, and it tells you the day fields are OR-ed.

33 built-in tools in one app. A field-by-field parser that expands *, ranges, steps and comma lists into explicit SETS, a builder that writes the expression for you, and a plain-English explanation generated from the parsed fields rather than looked up in a table; next and previous fire times found by SEARCHING forward, which is the only correct way, because cron is a set of matching minutes and not an interval; a duty-cycle view putting run duration against the schedule's own gap, and an overrun list naming the jobs that cannot finish before they fire again and the instances they stack to; an overlap view giving the INTERSECTING MINUTES of every colliding pair, a one-day SVG timeline, an hour-by-weekday heatmap, a concurrency-per-minute load view with the peak named, and a stagger suggestion that removes a collision and shows the new times; shared-resource contention, blackout, maintenance and business windows with a check for fires landing inside them, a multi-timezone view, and a DST view showing the 23-hour day where a 02:00 job never fires and the 25-hour day where it fires twice, stating which behaviour it assumes rather than implying every scheduler agrees; recorded runs against expected fires, a missed list, a drift view of recorded against expected start; plus CSV exports, a JSON backup and a Method page showing how the expansion and the next-fire search work.

Parse. Every value each field expands to, so an expression is read rather than guessed.

Overlap. Not a yes or no — the minutes two jobs actually share.

What's included:

• Cronwise.html
• Quick-Start-Guide.html
• How-To-Use-Guide.html
• README.txt
• LICENSE.txt

Includes a personalized welcome wizard, an interactive guided tour, a ⌘K command palette, light/dark themes with 8 accents, and one-click JSON backup & restore.

Cronwise is a planning, costing and record-keeping tool for software and infrastructure work. Every figure it reports is computed by a stated formula from the numbers YOU enter, and every figure carries its UNIT, because a millisecond, a byte, a request, a vCPU-hour and a user-minute are different quantities and confusing them is the classic failure in this field. Byte and month conventions are settings and are printed beside the figures they produced — 1 KB = 1,000 bytes and 1 KiB = 1,024 bytes are both correct and they disagree. Where something is consumed against an allowance, the consumed amount, the remaining amount floored at zero and the overage are reported separately, because a negative remaining renders as headroom and that is how an outage gets missed. Where a figure rests on an assumption — a hit ratio, a growth rate, a base event rate, an hourly price — it is labelled an assumption at the point of use and is yours to change. It runs entirely in your browser with no network access of any kind: it cannot reach a server, a registry or a cloud account, and it reports only what you recorded. It does not predict an outcome and is not a guarantee of uptime, of a deploy, of a bill, of compliance or of security posture, and nothing in it is legal advice.