What the forex swap calculator does
When you hold a forex or CFD position past the daily rollover — 5 pm New York time, usually midnight on the broker's server — the broker credits or debits a swap. It reflects the interest-rate difference between the two currencies plus the broker's markup, and it is quoted separately for longs and shorts. On a trade held for a day it is small; on a position held for weeks it can outweigh the spread and commission together. The calculator turns your broker's swap rates into money per night and over the whole holding period, triple-swap day included.
How to use it
- Choose long or short.
- Choose how your broker quotes swap: in points (the MetaTrader default), in pips, or as an annual percentage.
- Copy the swap long and swap short values from the symbol specification. A negative value is a charge, a positive value a credit.
- Enter the lot size and the pip value per lot in your account currency (the pip value calculator gives it), or, in percentage mode, the position's value.
- Pick the day you open the trade, the number of nights you hold it and the day your broker charges the triple swap.
Nights held counts the daily rollovers the position stays open through. A trade opened on Monday morning and closed on Friday afternoon crosses four rollovers: Monday, Tuesday, Wednesday and Thursday nights.
The formula
swap in points : per night = swap × (pip value ÷ 10) × lots
swap in pips : per night = swap × pip value × lots
annual % : per night = position value × rate ÷ 100 ÷ 360
days charged = nights held + 2 × triple-swap nights
total swap = per night × days charged
Most brokers price forex with five decimals (three on yen pairs), so one pip equals ten points. Percentage swaps in MetaTrader use a 360-day bank year; a few brokers use 365.
Worked example
Long 1 lot of EUR/USD with a swap long of −7 points and a swap short of +2.5 points; the pip value is $10.
- Per night: −7 × ($10 ÷ 10) × 1 = −$7.00.
- Opened on Monday and held 5 nights (Monday to Friday), with the triple swap on Wednesday: 5 + 2 = 7 days charged.
- Total: 7 × −$7.00 = −$49.00, the equivalent of 4.9 pips.
The same position held short would earn 7 × $2.50 = +$17.50.
Opened on Thursday and held 10 nights, the trade crosses two Wednesdays and pays 14 days of swap: −$98.
In percentage mode, a $116,000 position (1 lot at 1.1600) with a −2.2% annual long rate pays 116,000 × 2.2% ÷ 360 = $7.09 per night, or $49.62 over the same 7 days.
Why Wednesday is charged three times
Spot forex settles two business days after the trade. A position rolled on Wednesday moves its value date from Friday to Monday, across the weekend, so the broker applies three days of interest that night and none on Saturday or Sunday. Some brokers charge the triple swap on Friday for indices, commodities or crypto CFDs, and some crypto CFDs are charged every calendar day — check your broker's schedule.
Where swap rates come from
The swap follows the gap between the two currencies' short-term interest rates. Buying the higher-yielding currency can earn a small credit; buying the lower-yielding one costs. Brokers subtract a markup on both sides, which is why a pair can be negative in both directions. Rates are updated regularly and can change overnight after a central-bank decision, so copy today's values rather than last month's.
Common mistakes
- Ignoring swap in backtests. A strategy that holds trades for days can look profitable before financing and lose money after it.
- Counting calendar nights. Saturday and Sunday are not rollovers: their cost is already in the triple-swap day.
- Assuming a positive swap is free money. A carry trade earns interest while carrying the full exchange-rate risk.
- Using the wrong unit. A swap of −7 in points is 0.7 pip; entered as pips it would be ten times larger.
- Overlooking account terms. Swap-free (Islamic) accounts usually replace swap with an administration fee, often after a few nights.