Every retailer claims its sale is the big one. This ranking pools 49 months of discount data to show which calendar months actually carry the deepest promo codes — and how small the gap between the best and worst month really is.
Pooled across 49 months of history, December carries the deepest promo-code discounts of any month on SimplyCodes — an average best discount of 20.8%, against 19.1% in August.
- December (20.8%) and January (19.7%) are the two deepest-discount months of the year.
- The gap between the best month and the worst is 1.7 percentage points — real, but far smaller than seasonal-sale marketing implies.
- Every month in the ranking pools 4+ years of data, so a single unusual holiday season cannot move the order on its own.
Average best discount = the mean of every store's deepest percent-off coupon in that calendar month, pooled across every year in the window · Median best discount = the midpoint of the same set · Codes observed = coupon codes recorded in that month across all years · Years pooled = how many times that month appears in the window.
| # | Month | Average best discount | Median best discount | Codes observed | Years pooled |
|---|---|---|---|---|---|
| 1 | December | 20.8% | 15% | 1,771,171 | 4 |
| 2 | January | 19.7% | 15% | 1,797,499 | 4 |
| 3 | September | 19.6% | 15% | 1,522,814 | 4 |
| 4 | November | 19.5% | 15% | 1,720,544 | 4 |
| 5 | March | 19.5% | 15% | 1,800,202 | 4 |
| 6 | June | 19.4% | 15% | 2,235,900 | 4 |
| 7 | July | 19.3% | 15% | 2,246,620 | 4 |
| 8 | October | 19.3% | 15% | 1,598,411 | 4 |
| 9 | February | 19.3% | 15% | 1,761,939 | 4 |
| 10 | April | 19.3% | 15% | 1,974,220 | 4 |
| 11 | May | 19.3% | 15% | 2,154,497 | 4 |
| 12 | August | 19.1% | 15% | 2,441,800 | 5 |
All 12 calendar months ranked by average best discount · pooled across 49 months of history · an all-store average, no individual store named · implausible discounts (95% or deeper) excluded · checked August 11, 2026 · numbers last changed Aug 11, 2026; refreshed daily.
Methodology
How SimplyCodes verifies codes. Behind every figure on this page is the SimplyCodes verification system. Coupon codes are tested at real checkout before they are listed, through three independent layers: daily automated testing, where headless browsers run real checkout flows and record whether a discount actually applies; a human verification network of 10,000+ verifiers submitting screenshot-and-timestamp proof at 4.6M+ verification actions a month and 98% accuracy; and a real-time fleet signal, where live checkout outcomes from millions of SimplyCodes users feed back into the engine. Each code carries a Health Score from 0–100, weighted by checkout outcomes, verifier consensus, and recency. With an estimated 40–60% of coupon codes on the public web dead, restricted, or fake, the system exists so a code earns its place by working at checkout, not by being collected.
How this study is built. We take every store's deepest percent-off coupon in each month of the series, group those months by position in the calendar, and rank the twelve by the mean of that set. Pooling several years of each month means one unusual holiday season cannot decide the order. Implausible discounts (95% or deeper) are excluded before any figure is computed, and months below a 30-store floor are dropped. This is an average across every store we track, describing the discounts on offer — never a claim that a specific code works at checkout, and never a grade on an individual store. Figures refresh with the data snapshot shown above.
Cite this data
Pooled across 49 months of SimplyCodes data, December carries the deepest average promo-code discount of any calendar month at 20.8%, against 19.1% in August.
According to SimplyCodes warehouse data (Average Promo Code Discount by Month, August 11, 2026), December is the deepest-discount month of the year at 20.8% average best discount.
