The answer

The answer: how to calculate swap

Swap and overnight financing cost starts from one base rule: multiply the daily swap rate by your size (lots or quantity) and the number of charged nights. In a fictional example where you receive +¥150 per 1.0 lot each night and hold for 14 days, with two triple-days along the way, normal nights and triple-days combine into 14 charged nights and a cumulative of about +¥2,100. From there you layer on the triple-day schedule, weekend and holiday adjustments, trade direction (long or short) and instrument-specific rules to approach the real holding cost.

This is not one universal equation, though. Forex is usually quoted as swap points or an amount per lot, whereas index and single-stock CFDs commonly accrue “notional value x annual rate / day-count basis” per day, which changes the shape of the maths. After sorting out that difference, this guide checks a day-by-day timeline of normal and triple-day nights, totals from daily out to 365 days, scenarios where swap shrinks or reverses, and the days needed to recover transaction cost — all with one consistent fictional educational dataset. For where swap sits within total trading cost, see the complete trading cost calculation guide.

Definitions

Definitions: four types of swap and funding

“Swap,” “overnight financing” and “funding” are used interchangeably, but the way they are quoted and calculated splits into a few distinct forms. Confuse them and you end up applying the same equation to all, so it helps to sort out four types first. Across every type, what you receive or pay depends on direction and can reverse sign over time.

• Swap-point type (FX): quoted as “X points” or “X per lot” and estimated as daily rate x quantity x charged nights. The amount and the sign differ between long and short.
• Currency-amount type: quoted as an amount per night in the account currency. No conversion is needed if the rate is already in your account currency, but if the profit-and-loss currency differs, a separate conversion applies.
• Annualized / benchmark-linked type: derived by adding a spread to a policy or reference rate, then accruing it daily, so the nightly rate moves when interest rates move.
• CFD notional x annual rate / day-count type: common for index and stock CFDs, where one day is “notional x annual rate / 360 (or 365).” The long side can be a cost and the short side a credit, so the sign varies by instrument.

Unless noted otherwise, the prose, figures and tools in this article use the swap-point type (a daily rate per lot), and the annualized type is handled as a separate mode in the estimator later. Keep in mind that long and short swap usually differ, and in many cases one side leans positive while the other leans negative. Entry-side costs such as spread and commission are a separate topic: for converting pips to money see how much the forex spread costs, and for one-way and round-trip fees see the trading commission calculator.

General equation

A unit-aware general equation

First, write the cumulative swap for the swap-point type with units made explicit. Received amounts are positive; paid amounts are negative.

Substitute the fictional example: a daily rate of +¥150 / lot / night, a quantity of 1.0 lot, and a 14-day hold made up of 8 normal charged nights (x1), 2 triple-day nights (x3) and 4 non-charged weekend nights (x0). That gives the following.

The key point is that the two weekend nights are usually not charged separately at most forex brokers; the triple-day bundles them into a single crediting or charging event. So across a full week, “charged-equivalent nights” tends to converge on “calendar days held.” For the annualized (CFD) type the equation changes: use “one day (¥) = notional (¥) x annual rate / day-count basis (days)” and multiply by the holding days. The day-count basis is 360, 365 or another value depending on the instrument, so always verify the specification for your instrument.

Day by day

A 14-day timeline: normal nights and triple-days

The cumulative total does not rise by the same amount every day. The chart below plots each day’s charge (bars) alongside the running total (line) for the fictional example of 1.0 lot held for 14 days at +¥150 / night. Normal nights are x1, triple-days are x3 and weekends are x0, distinguished by label and value as well as color. Every figure is fictional educational data.

Laid out numerically, the way the total builds becomes clear. The table below shows the same fictional example as the chart (1.0 lot, +¥150 / night) day by day.

The total is 14 charged-equivalent nights for +¥2,100. Shift the triple-day placement, or hold for a span that does not divide into whole weeks, and the same number of days can land the cumulative higher or lower. That is exactly why the triple-day weekday and holiday adjustments must be verified per instrument on your broker’s official calendar.

Across periods

Daily to weekly to 30/90/365-day totals

If the nightly rate is assumed constant, the total compounds as the hold lengthens. The step chart below shows +¥150 / night building up over 30 days, jumping on triple-days and going flat over weekends. The longer the horizon, the more the fact that “the rate itself moves” outweighs these steps.

Summarized by period, the figures are as follows. All assume +¥150 / night stays constant and that a full-week average converges on days x rate.

This table is strictly a “if the rate does not change” view. In reality, as the next section shows, received swap moves day to day, and over a longer hold that variation increasingly drives the total. The same is true for the annualized CFD type: if the reference rate moves, the daily cost moves. For how required move and turnover relate to holding style, see the comparison of cost drag by trading style.

Read the range

Rate-change scenarios: shrink, zero and sign reversal

Received swap is not fixed. The rate can shrink with rate differentials, supply and demand, or broker adjustments, fall to zero, and at times reverse into a negative (paid) carry. The fan chart below applies -10%, -25%, -50%, zero and sign reversal to the base +¥150 / night and shows how far the 90-day cumulative spreads — a fictional sensitivity example. Read it as a tool for grasping a range, not as a forecast.

Numerically, the lower the rate and the longer the hold, the wider the gap in the total. If the sign reverses, what was a received holding benefit becomes a payment of the same magnitude.

Once you want to compare this range across several conditions at once, or switch it by holding period, a single one-off calculation stops keeping up. The CTA below is the entry point, but the natural start is to enter your own base rate and size for free and get a first read on the sensitivity.

Recover and offset

Recovery days and offsetting an adverse move

Received swap has two “catch-up” readings. One is the recovery days for the received swap to earn back the transaction cost (spread and commission) you paid on entry. The other is the offset days for received swap to fill an unrealized loss from an adverse price move. The intersection chart below shows how many days it takes for the +¥150 / night cumulative to catch up with a round-trip cost of ¥3,000 and an assumed adverse move of ¥9,000 (about 9 pips).

What must not be overlooked is that offset days rest on the strong assumption that “price does not move any further.” In the fictional example of about ¥1,000 / pip on 1 lot, a ¥9,000 adverse move is only about 9 pips, and even so it takes about 60 nights to fill with received swap. If price keeps moving against you during that time the offset cannot keep up, and if swap falls to zero or reverses, the offset stops altogether. High swap is not collateral against price risk. For reading break-even, cost ratio and the friction score, see the break-even and cost ratio guide.

Mini learning aid

Holding-cost and swap estimator

The mini calculator below takes a daily rate, size, charged nights, triple-days, transaction cost and an assumed adverse move, then shows cumulative swap, recovery days, offset days and the -25% / -50% / zero scenarios. It does not judge pass or fail, or “favorable versus adverse.” All calculation stays in your browser, and inputs are neither sent nor stored anywhere. The annualized (CFD) type is a separate mode that requires a day-count basis. First, so the page reads even with JavaScript disabled, here is a static worked table at the default values.

This calculation is a simplified learning aid based on the real trade cost calculator. The swap-point type assumes non-charged weekends and counts charged-equivalent nights as “normal nights + triple-day nights x multiplier,” while the annualized type estimates “notional x annual rate / day-count x holding days.” It does not include spread, commission, tax, execution slippage, currency conversion, dividend adjustments or rollover. If the profit-and-loss currency differs from your account currency, a separate conversion applies. For the full set of inputs including contract specifications, check SG Group’s free trade cost calculator.

Check it free

The free-calculator workflow, and where Pro and Premium fit

Once you have a rough read on swap, the next step is to turn it into numbers for your own account conditions. The free trade cost calculator covers one-way and round-trip transaction cost, a break-even estimate including spread, commission and swap, break-even pips and price, profit or loss per pip or point, cost ratio, friction score, and a daily-to-annual swap credit or debit check (including a triple-day estimate) plus recovery days — all from your inputs. Results also support amount-hidden sharing and add-to-home-screen. Because prices and specifications can change, they are not fixed in the body text; check the current scope on the plans page.

If all you need is to check a “one-off swap credit or debit” as covered here, Free is enough. When you want to line up the same trade under several conditions, view holding-day cost or break-even ladders, or drill into the sensitivity of swap-rate scenarios, adverse-move offset and recovery days, Pro’s in-session analysis comes into view. And when you need to audit swap and funding changes, dividend adjustments, rollover and currency conversion in an ongoing ledger, that is where Premium’s audit features and the ongoing cost audit and ledger guide apply. Differences in funding specifications by instrument are covered in the asset-class trading costs guide. Feature names, scope and pricing can change, so confirm the latest on the current service and plan pages before use.

Avoid these

Common mistakes and how to avoid them

Swap mistakes tend to fall into a few patterns. If any of these sound familiar, that is where to start reviewing.

• Forgetting to count triple-days: estimating the total from normal nights only and leaving out the triple-day that covers the weekend, so the figure drifts from reality.
• Assuming the triple-day weekday is fixed: deciding it is Wednesday and not confirming that it varies by broker, instrument and holiday.
• Treating received swap as fixed income: ignoring daily variation, zeroing and sign reversal, and assuming a guaranteed long-term credit.
• Using the same rate for long and short: estimating both directions from one number when the amount and sign differ by direction.
• Thinking swap can fill a price loss: overlooking that offset days are long, that price can keep moving, and that swap can stop.
• Calculating FX and CFDs with the same formula: confusing the swap-point type with the annualized type, and getting the day-count basis or notional wrong.
• Lumping in dividend adjustments and rollover: counting index-CFD dividend adjustments, futures rollover or crypto funding together with swap.

Summary

Summary: the main answer and your next step

Swap cost is fundamentally “daily rate x quantity x charged nights,” with the triple-day schedule, holidays, direction and instrument specifications layered on top. In the fictional example, +¥150 / night on 1.0 lot held for 14 days gave a cumulative +¥2,100, rising to +¥4,500 at 30 days, +¥13,500 at 90 days and +¥54,750 at 365 days. But received swap moves daily, and the total shifts sharply at -25%, -50%, zero and sign reversal. Recovering a ¥3,000 round-trip cost takes about 20 nights and offsetting a ¥9,000 adverse move about 60 nights — and that offset assumes price does not move any further. The FX swap-point type and the CFD annualized type use different formulas, and dividend adjustments and rollover are counted separately.

In practice: (1) confirm the rate, sign and triple-day weekday for your instrument on the official calendar, (2) estimate the cumulative by holding period, (3) read it as a range of scenarios, (4) treat recovery and offset days as figures that assume the rate persists, and (5) turn your own conditions into numbers in the free calculator. Work through that order and you will not be far off.

Related articles

Related reading

To check position size first, see the lot size calculation guide, and browse more English articles from the article library.