IMF World Economic Outlook October 2026: World Growth Is 3.1 or 2.5 Percent

The International Monetary Fund published the IMF World Economic Outlook, October 2026 on Tuesday, October 13, 2026, projecting world growth of 3.1 percent in 2026, down from 3.5 percent in 2025, and 3.4 percent in 2027. That 3.1 percent adds up world output with purchasing-power-parity weights; a few rows lower in the same Table 1.1, world growth based on market exchange rates is 2.5 percent for 2026. Anyone setting the IMF figure beside a U.S. number, a Federal Reserve projection or a dollar-based forecast now has to match the weights, the calendar and the revision baseline first.

The report carries two weightings and three calendars. Its U.S. forecast of 2.3 percent for 2026 is an annual average, while the Fed's 2.3 percent median of September 16, 2026 runs fourth quarter over fourth quarter. And its 0.2 point upgrade to 2027 world growth sits beside a 0.2 point cut to that year's fourth-quarter growth, both measured against April.

Two World Growth Rates in One Table

Table 1.1 of the IMF World Economic Outlook October 2026, Chapter 1, titled Overview of the World Economic Outlook Baseline, runs across pages 10 and 11. Its World Output row reads 3.5 for 2025, 3.1 for 2026 and 3.4 for 2027. A row named World Growth Based on Market Exchange Rates reads 2.9, 2.5 and 2.8. The gap is 0.6 percentage point in each year. Table 1.2 on page 12, at market exchange rate weights, repeats 2.9, 2.5 and 2.8 in its World Output row.

The chapter's headline sentence uses the first row: “Global growth is projected to decelerate from 3.5 percent in 2025 to 3.1 percent in 2026 before recovering to 3.4 percent in 2027, unchanged from that in April for 2026 and revised upward by 0.2 percentage point for 2027 (Tables 1.1 and 1.2).” Its numbers come from the PPP row, and its unchanged-from-April label for 2026 holds only for that row; on market-rate weights, the 2026 forecast is lower than in April.

The choice matters when the world figure meets a single-country forecast. The IMF's U.S. figure of 2.3 percent for 2026 trails the PPP-weighted world by 0.8 point and the market-rate world by 0.2 point. In 2027 the gaps are 1.1 and 0.5. A claim that the U.S. economy trails the world is strong on one row and marginal on the other.

What Each Weight Measures

The IMF World Economic Outlook October 2026 Database Appendix assigns weights by type of data. For financial variables the weight is dollar GDP: “Country group composites for exchange rates, interest rates, and growth rates of monetary aggregates are weighted by GDP converted to US dollars at market exchange rates (averaged over the preceding three years) as a share of group GDP.” For the real economy it switches: “Composites for other data relating to the domestic economy, whether growth rates or ratios, are weighted by GDP valued at purchasing power parity as a share of total world or group GDP.”

Table 1.2's note applies the dollar method to the growth rows: “The aggregate growth rates are calculated as a weighted average, in which a moving average of nominal GDP in US dollars for the preceding three years is used as the weight.” Table 1.1's ninth footnote, quoted further below, measures its quarterly coverage of world output at PPP weights.

The two world rows therefore average the same country growth rates with different weights. Since the PPP average is higher by the same 0.6 point in every year, the PPP weights lean toward faster-growing economies compared with dollar weights. The appendix's revision history dates the current PPP weights to October 2024, when they were updated after the World Bank Group's 2021 International Comparison Program survey.

Which row fits depends on the question. For world output volume, the PPP row is the IMF's headline. For anything earned or spent in dollars, such as export demand or dollar revenue, the market-rate row is the closer match. The appendix itself aggregates fiscal data, external sector statistics and trade on a dollar basis. A similar valuation question runs through the IMF's reserve data, covered in the faultlinesweekly reading of the COFER dollar share.

Raised, Unchanged or Slower: Three Baselines for One 3.1

The 2026 figure of 3.1 percent reads as an upgrade, as no change, or as a slowdown, depending on the baseline:

• Against 2025: 0.4 point below the 3.5 percent shown for 2025. That is slower growth, not a revision.
• Against the July 2026 WEO Update: the difference column shows +0.1, so July's figure was 3.0. That is the upgrade.
• Against the April 2026 WEO: the difference column shows 0.0. The chapter's sentence takes this baseline.

Footnote 1 governs every difference column: “Difference based on rounded figures for the current, July 2026 WEO Update, and April 2026 WEO forecasts.” A +0.1 can reflect a much smaller unrounded change, and a 0.0 can conceal one just under 0.1.

The market-rate row differs for 2026: +0.1 against July but −0.1 against April, when its forecast was 2.6. On PPP weights, October restored April's forecast; on market-rate weights, it stays below it. For 2027 both rows show +0.2 against April and 0.0 against July.

The IMF's 2.3 and the Fed's 2.3 Run on Different Clocks

The chapter's U.S. sentence reads: “In the United States, growth is projected at 2.3 percent in 2026 and in 2027, unchanged from April for 2026 and an upward revision of 0.2 percentage point for 2027.” Table 1.1 shows 2.3 for 2025 as well: three identical annual figures.

The continuation of Table 1.1 on page 11 has a section headed Q4 over Q4, where the United States reads 2.0 for 2025, 2.5 for 2026 and 2.1 for 2027. An annual average compares a year's average output level with the previous year's average; a Q4-over-Q4 rate compares the last quarter of each year. One projected path gives a flat 2.3 on the first clock and an acceleration followed by a slowdown on the second.

The Federal Reserve Summary of Economic Projections, September 16, 2026 puts its median change in real GDP at 2.3 percent for 2026 and 2.4 percent for 2027, up from June medians of 2.2 and 2.3. Its Table 1 note sets the clock: “Projections of change in real gross domestic product (GDP) and projections for both measures of inflation are percent changes from the fourth quarter of the previous year to the fourth quarter of the year indicated.”

On matching clocks the two part ways. For 2026, the IMF's 2.5 is 0.2 point above the Fed median and above the Fed's central tendency of 2.2 to 2.4, though inside its range of 2.1 to 2.6. For 2027, the IMF's 2.1 is 0.3 point below the Fed's 2.4, below the central tendency of 2.2 to 2.6, and inside the range of 2.0 to 2.9. The apparent agreement at 2.3 for 2026 pairs an annual average with a fourth-quarter rate.

A third clock sits in the source data. The BEA GDP third estimate for the second quarter of 2026, released September 30, 2026, opens: “Real gross domestic product (GDP) increased at an annual rate of 2.2 percent in the second quarter of 2026 (April, May, and June), according to the third estimate released today by the U.S. Bureau of Economic Analysis (BEA).” First-quarter growth was revised to 2.5 percent. BEA's note fixes the unit: “Percent changes in quarterly seasonally adjusted series are displayed at annual rates, unless otherwise specified.” A 2.2 percent quarter is one quarter's change compounded to a yearly pace. The release also carries the 2026 annual update of the national accounts and schedules the third-quarter advance estimate for October 29, 2026.

A 2027 Upgrade That May Have Been Built in 2026

The Q4-over-Q4 difference columns move differently from the annual ones. Against the April 2026 WEO:

• World, annual: 0.0 for 2026 and +0.2 for 2027.
• World, Q4 over Q4: +0.2 for 2026 and −0.2 for 2027.
• United States, annual: 0.0 for 2026 and +0.2 for 2027.
• United States, Q4 over Q4: +0.3 for 2026 and 0.0 for 2027.

Both 2027 headline upgrades are 0.2 point. On the fourth-quarter clock, U.S. growth within 2027 is unchanged and world growth within 2027 was cut by 0.2. The upward revisions sit instead on 2026's fourth-quarter clock: 0.3 for the United States and 0.2 for the world.

This article's own reading links them. Raise the output level at the end of 2026 and the average level of 2027 rises with it, lifting 2027's annual growth even if growth within 2027 is unchanged. The same mechanism leaves the 2026 annual figure almost untouched, since a stronger year-end lifts only the last part of the 2026 average. Against July the pattern repeats: world Q4-over-Q4 growth up 0.2 for 2026 and down 0.1 for 2027, and U.S. growth up 0.2 for 2026 and unchanged for 2027.

The world quarterly row is also a slightly different aggregate. Footnote 9 reads: “For world output, the quarterly estimates and projections account for approximately 90 percent of annual world output at purchasing-power-parity weights.” About a tenth of world output by PPP weight sits outside the quarterly figures, so the 3.1 percent Q4-over-Q4 rate for 2026 and the 3.1 percent annual rate rest on different country coverage.

Two Footnotes That Change the Unit

Two more footnotes in Table 1.1 change a familiar label. Footnote 6 defines the oil price as a “Simple average of prices of UK Brent, Dubai Fateh, and West Texas Intermediate crude oil.” It adds: “The average price of oil in US dollars a barrel was $67.74 in 2025; the assumed price, based on futures markets, is $95.74 in 2026 and $87.39 in 2027.” The 2026 assumption is 41.3 percent above the 2025 average, and the 2027 assumption is 8.7 percent below 2026. Matching it to a Brent quote compares one crude with an average of three. For a U.S. energy price that also shifts between series, see how a gasoline rise grew between two measures in the September CPI.

India's row runs on another calendar: “For India, data and projections are presented on a fiscal year (FY) basis, with FY 2025/26 (starting in April 2025) shown in the 2025 column.” The footnote adds: “India’s growth projections are 7.4 percent for 2026 and 7.0 percent for 2027 on a calendar year basis.” For India, the column headed 2025 holds a year that ends in March 2026.

Concrete Framework

Six checks settle which IMF number belongs in a comparison:

1. Weight. Set 3.1 percent for 2026 against PPP-weighted world figures and 2.5 percent against dollar-weighted ones. The 2025 bases are 3.5 and 2.9.
2. Clock. Annual average (IMF 2.3 for the United States in 2026), Q4 over Q4 (IMF 2.5, Fed median 2.3), or one quarter at an annual rate (BEA 2.2 for the second quarter). Only like clocks compare.
3. Revision baseline. July or April 2026, on rounded figures. A +0.1 against July and a 0.0 against April describe one October number.
4. Coverage. The world Q4-over-Q4 rows cover approximately 90 percent of world output at PPP weights; the appendix computes group composites, unless noted otherwise, when 90 percent or more of group weights is represented.
5. Footnote units. Oil is a three-crude average; India's row is a fiscal year.
6. Vintage. Table 1.1 holds real effective exchange rates at the levels prevailing from July 31, 2026, to August 28, 2026. The Fed's projections were submitted for its September 15–16 meeting. BEA's annual update came on September 30.

The clock check yields a testable condition. On BEA's current history, with the first quarter at 2.5 percent and the second at 2.2 percent at annual rates, a Q4-over-Q4 forecast g requires a second-half average pace h, at an annual rate, from (1 + h)² = (1 + g)⁴ / (1.025 × 1.022):

• IMF path, 2.5 percent: about 2.65 percent, or 2.55 to 2.75 across the rounding band of 2.45 to 2.55.
• Fed median path, 2.3 percent: about 2.25 percent, or 2.15 to 2.35 across the band of 2.25 to 2.35.

Given a third-quarter figure, the fourth quarter each path then needs, all at annual rates:

Third quarter	Fourth quarter needed, IMF 2.5 path	Fourth quarter needed, Fed 2.3 path
2.0	3.3	2.5
2.5	2.8	2.0
3.0	2.3	1.5

The paths sit about 0.4 point apart on the second-half average, so a third quarter near 2.5 percent leaves the fourth quarter to decide between them. These are requirements on today's BEA history, not the forecasters' own quarterly paths, which neither table publishes.

What to Watch Next Week

The next fixed date in the documents collected here is BEA's advance estimate of third-quarter GDP on October 29, 2026. Four kinds of figures will circulate next week.

• Third-quarter estimates and nowcasts. These are one quarter at an annual rate. Set them against the computed second-half averages of about 2.65 percent (IMF 2.5 path) and 2.25 percent (Fed 2.3 path), not against 2.3 or 2.5.
• IMF-versus-Fed comparisons. Beside the Fed's 2.3 and 2.4 belong the IMF's 2.5 and 2.1, not its annual 2.3.
• World growth comparisons. A forecast aggregated at market exchange rates belongs beside 2.5 percent for 2026, not 3.1.
• Oil. The IMF's $95.74 is a 2026 average of three crudes; a week of moves in one benchmark tests it only loosely.

What Would Invalidate This

• Vintage of the forecasts. The second-half thresholds use BEA's history after the September 30 annual update. The Fed's projections predate it, and the IMF's U.S. path may too. If the update moved the first two quarters materially, each forecaster's own implied second half differs from the 2.65 and 2.25 computed here.
• Scope of the PPP rule. The appendix's PPP sentence covers other data relating to the domestic economy and names no single variable. The reading that World Output uses PPP weights rests on that sentence, on footnote 9 and on the separate market-rate row in Table 1.1. Box A2 of the October 2024 Statistical Appendix, which summarizes the revised PPP weights, was not opened.
• A lower end-2025 level. If the IMF lowered its estimate of output at the end of 2025, the 2026 Q4-over-Q4 rate would rise with no higher end-2026 level, and the 2027 annual upgrade would need another cause. The tables collected carry no 2025 revision column, and the chapter text collected offered no sentence on the Q4-over-Q4 revisions, so the carry-over reading is this article's arithmetic rather than the IMF's stated reason.
• Rounding. The U.S. contrast for 2026, 0.0 on the annual clock against +0.3 on the fourth-quarter clock, survives the rounding band; a lone +0.1 against July might not.
• Rows read once. The advanced-economy and emerging-market rows of both tables and Table 1.1's China row were read once and are not cited. The Fed's definitions of median, central tendency and range sit in footnotes that were not collected.

Until one of these tables is revised, the October 2026 outlook supports two world growth rates for 2026, 3.1 and 2.5 percent. The same year carries three U.S. figures: 2.3 on the annual clock, 2.5 on the fourth-quarter clock and, for the second quarter alone, BEA's 2.2.