Quick Answer: The header's “24h Change” compares the current BTC price with a reference roughly 24 hours earlier. The percentage beside a selected weekly candle compares that candle's current price with its weekly open. The two clocks start at different times, so their percentages can differ even on the same market screen. Confirm the exchange's exact reference-price method before trying to reproduce the header figure.
What does the 24-hour number measure?
A 24-hour change describes movement across a recent one-day window. A standard simple-return calculation is:
(current price ÷ 24-hour reference price − 1) × 100
Some interfaces use the price exactly 24 hours ago; others use a rolling ticker or a specific reference-price convention. The label alone does not identify every implementation detail. Check the market's data definition and timestamp before attempting an exact reconciliation.
The user-supplied Phemex BTC/USDT screenshot, captured at 11:30:50 UTC+8 on November 6, displays $75,965 and “24h Change” of −5.87%. Those are dated observations. They are not current market values when this article is read.
What does the weekly candle measure?
A candlestick records an open, high, low, and close for its selected interval. For a weekly candle that is still forming, the displayed close is normally the latest price used by the chart, not a final weekly close. Its change from open can be estimated as:
(current candle price ÷ weekly open − 1) × 100
In the same screenshot, the weekly candle's open is $78,354 and the displayed close is $75,965. Those values reproduce the chart's −3.05% label when put into the formula above. The candle's high and low are extremes within the week, not the starting price for that percentage. The header's −5.87% uses a different starting price. There is no arithmetic conflict.
Eligible readers can use the Phemex spot screen to inspect the current BTC/USDT quote, switch chart intervals and review order details. The article's November 6 percentages are historical examples; do not use them as today's entry levels. Spot trading still carries price and execution risk.
Why can the difference become large?
The weekly open may be several days old, while the 24-hour reference moves forward continuously. Bitcoin could rise early in a week, then fall sharply during the last day. In that case, the 24-hour decline can be greater than the current week's decline. The reverse can also happen.
Changing the chart from weekly to daily or hourly changes the candle's open and thus its displayed percentage. It does not change the definition of the header's 24-hour figure. Different venues and trading pairs may also have different prices, so compare like with like.
Reproduce the weekly figure before interpreting the market
The screenshot provides everything needed for the weekly calculation: the selected interval is W, the current candle shows an open of $78,354 and a displayed close of $75,965. Subtracting the open from the displayed close gives −$2,389; dividing by $78,354 gives roughly −3.05%. This is a weekly open-to-current move. It does not say what Bitcoin did during the last 24 hours alone.
To verify another screenshot, first read the selected chart interval and the candle's OHLC line. Make sure the highlighted candle is the current one; hovering an older candle will show that older candle's numbers while the page header may still describe the live market. Next calculate (C/O - 1) × 100. If the result differs slightly from the label, inspect rounding and whether the chart's current price updated between your observations.
The header's 24-hour figure needs a different starting price. If the current price is $75,965 and the reported change is −5.87%, an approximate reference price can be recovered as 75,965 ÷ (1 - 0.0587), or about $80,704. That is an arithmetic back-calculation, not an independently verified Phemex reference quote. The exact market-data method and display rounding may cause a small difference. The important point is that $80,704 is far from the week's $78,354 open.
How do daily candles differ from a rolling 24-hour change?
A daily candle starts at the chart provider's chosen day boundary, often stated in UTC. A rolling 24-hour comparison starts relative to the current observation time. At 11:30 UTC+8, a rolling window reaches back to around 11:30 UTC+8 on the previous day; a daily candle may have opened at a fixed midnight boundary. Both can cover roughly one day, but their start and end points differ. If price moved sharply near the boundary, the displayed percentages can be materially different.
Weekly candles have another wrinkle: the current week has not finished. Its close, high, low and percentage can continue changing. A previous completed week's candle is fixed, subject to any later data-vendor correction, while the live header remains rolling. State whether you are discussing a completed candle or one still forming.
Which figure should a reader use?
Use the 24-hour change when the question is “How much has this market moved since roughly this time yesterday?” Use the current weekly candle when the question is “How far is price from this week's open?” Neither is a substitute for a trade plan. A large negative 24-hour figure can coexist with a smaller negative weekly figure without indicating an error or an imminent reversal. Check the exact market pair, timing and order-book conditions before interpreting either number.
One final check matters when comparing screenshots from different sites: make sure both pages refer to the same product. BTC/USDT spot, BTC/USDT perpetual futures and an index-derived Bitcoin quote can have different prices at the same second. A futures chart may also show mark price or last traded price, while the spot screen shows executed spot trades. If the starting and ending prices come from different products, even a correctly applied percentage formula answers the wrong question. Record the pair, venue, chart interval and observation time alongside any percentage you share.
FAQ
Is the weekly candle's percentage final before the week ends?
No. The latest candle changes as new trades arrive until the interval closes.
Does a 24-hour change mean the last daily candle's change?
Usually not. A rolling 24-hour period and a calendar-day candle can start at different times. Check the platform's own market-data definition for the exact clock.
