Calculator Updated 2026-09-12 Runs in your browser By Ivo Renner

Session and index-mode clock

The same contract is priced differently at 10am New York than at 3am, and differently again on a Saturday. This clock tells you which US equity session your browser thinks it is, which price-index mode that session implies, and how long you have until the next funding settlement. It is a derived indicator, not a feed from Binance — the limits are stated plainly below.

The session to index-mode mapping

Binance's FAQ describes how the price index behaves in each state of the underlying market. This is the mapping the clock applies, and it works without JavaScript because the table is static:

The last row is the newest and the least intuitive. Introduced in mid-2026, orderbook EWMA mode derives the index from Binance's own order-book impact price with exponential smoothing instead of vendor data — the exchange pricing the contract off itself when there is nothing else to price it off. Binance's FAQ documents it for the Hong Kong lunch break, among other cases. On exit from that mode, the index transitions gradually via a weighted blend over roughly one minute, in Binance's phrasing, "to prevent sudden price jumps".

Eastern times are given rather than UTC because the boundaries are defined in Eastern and the UTC offset changes twice a year with US daylight saving. During US daylight time the regular session runs 13:30–20:00 UTC; during standard time it runs 14:30–21:00 UTC. The clock handles the conversion through your browser's time-zone database, which is one of the few things about it you can rely on.

The US market holiday calendar

The clock does not detect holidays. That is a limitation of the clock, not of the information — the US equity market holiday calendar is public, fixed by rule, and about ten dates a year. So here it is, and reading it is the manual check the clock cannot do for you.

On a holiday the cash market is closed, but the equity perpetual’s index can still move using Orderbook EWMA. Funding continues on the contract’s own schedule. A cash-market closure does not freeze the perpetual or stop it responding to news.

The UTC column shifts because the closure is defined in Eastern time and the Eastern offset is not constant. US daylight time runs to 1 November in 2026 and from 14 March to 7 November in 2027; inside that window the regular session is 13:30–20:00 UTC, outside it 14:30–21:00 UTC. All three half-days above fall in standard time, which is why 13:00 ET is 18:00 UTC on each of them.

This table is partial by construction. It covers scheduled US equity market closures and the half-days we are confident of; exchanges confirm the half-day schedule annually, and unscheduled closures (weather, a national day of mourning, a systems failure) cannot be tabulated in advance. Where we were not confident of a date, the row is absent rather than guessed. Non-US contracts keep their own calendars and are not in this table.

What to do with it

Two practical uses, and they are the same two as for a weekend.

A holiday leaves a different reference market. The perpetual can price news through its own order book while cash trading is unavailable. Reopening can still produce a sharp move as external prices return. Use the gap calculator as a hypothetical price shock, not as a prediction that all news waits until Monday.

An early close changes the regular-session boundary. On 27 November 2026 the cash session ends at 13:00 Eastern, or 18:00 UTC. This clock will not automatically detect that. An early close does not imply an immediate frozen index: extended-session and unavailable-data rules still matter. See trading outside US market hours.

The funding countdown

Funding schedules are contract-specific. Choose the interval from your contract’s current parameters: eight hours gives 00:00, 08:00 and 16:00 UTC; four hours adds 04:00, 12:00 and 20:00 UTC. Binance moved nine named contracts to four hours on 10 September 2026 in an official adjustment notice. The default here does not select a contract for you.

For the eight-hour example, 05:42:00 UTC gives a countdown of 02:18:00 to 08:00. At 16:00:01, eight hours gives 07:59:59 to 00:00; selecting four hours instead gives 03:59:59 to 20:00. All these examples assume settlement on a UTC hour boundary.

A paying position held through settlement can incur that payment. Waiting until after settlement to close does not avoid it. Timing alone is not a reason to open or close: price movement, liquidity and execution costs also matter. Use the funding calculator for the cost scenario and confirm the actual timestamp in the contract interface.

Non-US contracts run on their own clocks

The clock above models US sessions only. Hong Kong, Korean and mainland Chinese underlyings use their own local trading schedules; examples in our historical roster are not a complete current inventory.

Those markets keep their own holiday calendars, which this clock knows nothing about either. Korean, Chinese and Hong Kong equity perps covers the sessions, the holidays and the quanto mechanism that treats one Hong Kong dollar as one USDT for margin purposes.

Why the mode is worth watching

The session tells you which reference inputs may be available. It does not by itself tell you whether a stop will fill. Under Orderbook EWMA, the equity index is smoothed from order-book impact prices, while the mark uses the standard median calculation described in the current https://www.binance.com/en/support/faq/detail/fe7dcdf24f1943d98b368f5f9f744398. Index construction and mark-price construction are separate steps.

Cash-market closures can reduce external price information while the perpetual continues moving. A stop remains exposed to gaps, trigger-price differences and slippage in any session. The gap calculator models a chosen adverse move rather than a guaranteed reopening loss.

For the current mechanics, read the index and mark-price guide and the out-of-hours guide. The official FAQ states that Orderbook EWMA replaced Fixed mode for equity closures from 16 May 2026. Rules checked 11 September 2026.