UptoolOpen a card and get unstuck: calendar math and Unix, meeting windows across cities with a live zone map, and IP plus draft helpers when the spec matters. Share a single URL with your team in English, Spanish, or Portuguese. No sign-in, runs in your browser.
Tools
Pick a start date and how many days to add. Turn on time and a custom time zone when you need wall-clock precision; otherwise we use noon in your zone to avoid daylight-saving surprises. Everything you set is reflected in the address bar for sharing.
Choose your anchor date and how many days to move backward. Add time-of-day and an explicit zone when it matters; the tool defaults to your browser zone. Your choices stay in the URL so you can bookmark or send the link.
Compare two dates for a simple day count, or enable hours and minutes for a real span, including different end zones when you override the clock. Plain calendar math when time is off; zone-aware instants when it is on. State lives in the query string.
Enter how many seconds or milliseconds you want to express. Switch the input to milliseconds when your value counts ms. Pick a full breakdown (approximate years and months) or a hours-focused summary. Your input and options stay in the URL.
Paste a Unix timestamp in seconds or flip the switch for milliseconds. We show a clear local-style date and time in your browser zone or a zone you choose. Copy the long form, ISO UTC, wall time, or raw seconds and milliseconds.
Pick the calendar date and time of day (seconds supported). Use the paste button next to the date to open a field where you paste with Ctrl+V (no browser permission). ISO, Unix, or yyyy-mm-dd. Toggle a custom IANA zone or use your browser zone. Copy seconds, milliseconds, or ISO UTC.
The day runs from midnight to midnight in your home zone (house icon). Hover the timeline for a quick preview, click to choose an hour, then drag the ends to widen or narrow the window in 30-minute steps. Add cities from the list and send the page link to share the same view.
Search for a city or place, or explore colored regions on the map. The bar along the bottom is a UTC guide by longitude; hover a segment to highlight matching areas. Red dots mark zone centers (you can hide them). Save places to compare local times and offsets side by side.
Search for a city first, then add places to your list. Each row shows live local time, offset vs UTC, and offset vs home. Tap the house icon on a row to make that place home, or open Change home in the list header for any zone. Home defaults to your browser time zone; the info button explains how that works.
Enter a.b.c.d/prefix, a.b.c.d with a second line for prefix or mask, or two tokens a.b.c.d m.m.m.m. Then pick a longer child prefix (or the matching usable-host count) to list every equal subnet inside the parent block. A sample calculation loads by default so you can explore binary view, class, scope, and the subnet table before you change the inputs.
IPv6 has no IPv4-style broadcast; this tool shows the subnet ID (network), last address in the prefix, and how many addresses the prefix covers. A sample result is calculated when the page opens.
IPv8 on this site always means the IETF draft proposal, not a finished standard or vendor feature set. Use it to read along with the draft; compare anything operational with your own design docs and routers.
App home pages
Add or subtract whole days, count days between dates, decode or encode Unix epochs, and break down long durations. Runs in your browser with shareable URLs.
Time zone converter for several cities on one timeline plus a time zone map with search, UTC offsets, and saved places. Private, multilingual, shareable links.
IPv4 and IPv6 subnet math in the browser, plus a draft-only IPv8 hub (Internet-Draft thain-ipv8): ASN dot notation, routing-prefix classes, reserved ranges, hosts per ASN, guide, and protocol comparison.
Free to use
Every app listed here is free: no paywall, no account. Open a tool and get to work.
Uptool lists small, focused web utilities you can open instantly. The date calculator covers add days to a date, subtract days, days between two dates, Unix timestamp to date, date time to Unix, and duration from seconds or milliseconds, all with optional zones and links you can send to a teammate. The time zones app pairs a multi-city time zone converter on one draggable timeline with a searchable time zone map backed by OpenStreetMap-style context and tz-lookup. The IPv8 calculator summarizes the Internet-Draft address model with ASN dot notation conversion, prefix classification, reserved ranges, and an IPv4 vs IPv6 vs IPv8 comparison. Everything runs client-side in the browser: no paywall, no account. More tools will ship here over time; use the filters above to narrow the list.
Add or subtract whole days, count days between dates, decode or encode Unix epochs, and break down long durations. Runs in your browser with shareable URLs.
You can rely on it when you need to:
Outputs update as you type, and the address bar mirrors your choices so you can bookmark or share a single URL instead of retyping dates in Slack or spreadsheets.
Time zone converter for several cities on one timeline plus a time zone map with search, UTC offsets, and saved places. Private, multilingual, shareable links.
You can rely on it when you need to:
Everyone opens the same configured view, so you spend less time correcting “wait, which 9am?” messages and more time locking the slot that actually works.
IPv4 and IPv6 subnet math in the browser, plus a draft-only IPv8 hub (Internet-Draft thain-ipv8): ASN dot notation, routing-prefix classes, reserved ranges, hosts per ASN, guide, and protocol comparison.
You can rely on it when you need to:
The tools cite draft-thain-ipv8-00 and companion drafts. They help you navigate notation and tables faster than scrolling a PDF on a phone.