South Korean won (KRW) exchange rate API

Korea is a large exporter of semiconductors, cars and ships, and the won is one of the more actively traded Asian currencies. Because of that, it often reacts quickly to global risk sentiment and to news from the Korean peninsula. For developers the won shares a trait with the yen: no decimals, and four-digit rates against the dollar. The fxapi KRW exchange rate API returns full-precision rates either way and leaves rounding to you.

KRW facts for developers

• Where it’s used: South Korea. (North Korea uses its own won, KPW.)
• Symbol and formatting: ₩ before the amount, comma thousands separator, no decimals: ₩1,250,000. In Korean text 원 usually follows the number.
• Minor unit: 0 decimals. The jeon is not used.
• Central bank: the Bank of Korea.
• Regime: free float since December 1997, with occasional smoothing operations. Much offshore trading in the won happens through non-deliverable forwards.
• Events in the historical data: the won weakened sharply against the dollar during the 2008 financial crisis. On the evening of 3 December 2024 (Korean time) a brief martial-law declaration sent the won sharply lower overnight; compare end-of-day values for 2 and 4 December 2024 – the sample date on this page.

Get KRW rates with the fxapi API

/v1/historical and /v1/latest work on every plan. This PHP snippet compares USD/KRW across that December 2024 episode and converts a dollar price into whole won:

<?php
function usdKrw(string $date): float
{
    $ch = curl_init('https://api.fxapi.com/v1/historical?' . http_build_query([
        'date'       => $date,
        'currencies' => 'KRW',
    ]));
    curl_setopt_array($ch, [
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_HTTPHEADER     => ['apikey: ' . getenv('FXAPI_KEY')],
        CURLOPT_TIMEOUT        => 10,
    ]);
    $body   = curl_exec($ch);
    $status = curl_getinfo($ch, CURLINFO_HTTP_CODE);
    curl_close($ch);
    if ($status !== 200) {
        throw new RuntimeException("fxapi returned HTTP $status for $date");
    }
    return json_decode($body, true)['data']['KRW']['value'];
}

$before = usdKrw('2024-12-02');
$after  = usdKrw('2024-12-04');
printf("USD/KRW %.2f -> %.2f (%+.2f%%)\n", $before, $after, ($after / $before - 1) * 100);

// KRW has no minor unit: round converted prices to whole won
$priceUsd = 49.99;
printf("$%.2f ≈ ₩%s\n", $priceUsd, number_format(round($priceUsd * $after)));

More on rounding in currency rounding and precision; the PHP guide covers caching. For the full period move in one call use the free fluctuation endpoint, and for any other date the historical exchange rates API. The Japanese yen is the other major zero-decimal currency.

Things to watch

• Never send fractional won to payment providers – round to whole won before charging.
• Tiny inverse rates. KRW-based values (USD per 1 won) need many significant digits; don’t truncate them to 4 decimals.
• Asian trading hours. Big moves can happen outside European and US hours; end-of-day values are in UTC.

Popular KRW pairs

Request any of these pairs – or any other combination of the 190+ supported currencies – with base_currency=KRW:

Monthly averages and fluctuation for KRW

# Monthly average KRW rates for 2025 (IAS 21 / ASC 830)
curl -G "https://api.fxapi.com/v1/average" \
  -d date_from=2025-01-01 -d date_to=2025-12-31 -d period=month \
  -d base_currency=KRW -d currencies=USD,JPY,CNY \
  -H "apikey: $FXAPI_KEY"

# How did KRW move over the last year?
curl -G "https://api.fxapi.com/v1/fluctuation" \
  -d date_from=2025-10-01 -d date_to=2026-10-01 \
  -d base_currency=KRW -d currencies=USD,JPY,CNY \
  -H "apikey: $FXAPI_KEY"

See the historical exchange rates API, average rates API and documentation for every parameter.

KRW is one of 190+ currencies in fxapi, the foreign exchange rates API for developers – live rates, daily history since 1999 and monthly averages with one API key.

Frequently asked questions