DayZ Day/Night Cycle Calculator
How long should a day and a night last on your server in real time? Pick your map and desired durations — the calculator uses the real in-game sunrise and sunset times (they change with the calendar date!) and produces the exact serverTimeAcceleration and serverNightTimeAcceleration values, ready to paste into your serverDZ.cfg.
Map
Engine position: 56° N, 30° E (from the game files)
Server date
Calculated for today (29.7.2026) — with SystemTime the server starts at the machine's local date and time on every restart.
Recommended: 1–6 hours
Recommended: 10–60 minutes
Presets
In-game 24h clock
serverTimeAcceleration
8.16×
→ your day lasts 2h of real time
serverNightTimeAcceleration
1.88×
night runs 15.34× faster in total → 30m of real time
One full cycle in real time
Full cycle: 2h 30m
Cycles per 24 h: 9.6
Night share: 20%
serverTime = "SystemTime"; serverTimeAcceleration = 8.16; serverNightTimeAcceleration = 1.88; serverTimePersistent = 0;
Sliders and presets for day and night length — including the official server settings (3 h / 40 min).
Real astronomy per map and date: the engine computes sunrise and sunset from each terrain's latitude, and so does this calculator.
Finished serverDZ.cfg block with serverTime, both multipliers and serverTimePersistent — copy with one click.
How the calculation works
DayZ runs on a 24-hour in-game clock. serverTimeAcceleration (0.1–64) is a multiplier on that clock: at 6×, four real hours become one full in-game day. serverNightTimeAcceleration (0.1–64) kicks in additionally between sunset and sunrise and multiplies with the first value — at 6× × 4× the night runs 24 times faster than real time.
How many in-game hours are day vs. night depends on the map and the calendar date. Each terrain has a geographic latitude in the game files (Chernarus 56° N, Livonia 54° N, Sakhal 55.5° N) from which the engine computes the sun's path astronomically: mid-June Chernarus gets ~17.5 h of daylight, late December barely 7 h.
The calculator therefore first determines sunrise and sunset for your chosen map and date, then solves for both multipliers: serverTimeAcceleration = in-game daylight ÷ desired day length, and serverNightTimeAcceleration = (in-game night ÷ desired night length) ÷ serverTimeAcceleration. Both values are clamped to the allowed range 0.1–64.
Frequently asked questions
Why do my day and night lengths change over the weeks?
With serverTime = "SystemTime" (or serverTimePersistent = 1) the in-game date follows the calendar — and with it the real day length: summer days are long, winter days short. If you want a constant rhythm, set a fixed serverTime date; a popular choice is a date near an equinox (late March / late September) where day and night are roughly equal.
When exactly does serverNightTimeAcceleration apply?
From sunset to sunrise — the engine switches as soon as the sun is below the horizon. During that phase the effective speed is serverTimeAcceleration × serverNightTimeAcceleration.
What are the limits for the two values?
Both accept 0.1 to 64. Values below 1 slow time down (0.5 = half speed). On top of that, the engine caps the combined night speed (day × night multiplier) at 64× — we verified this with time-lapse measurements on a real DayZ 1.29 server. The calculator respects both limits and warns you when your desired durations aren't exactly reachable.
Do the values match the official servers?
The "Official" preset reproduces Bohemia's setup on official servers: roughly a 3-hour day and a 40-minute night. Pick it and copy the generated config block.
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