Methodology & sources
Every rate table, window, formula, and limit of the peak-surcharge calculator, in the open. Found an error? support@whetstonetools.com.
Last updated August 31, 2026 · 2026-27 season schedules, verified 2026-08-31
1 · Scope
The tool computes the cost of published all-shipper peak/demand surcharges — the temporary per-package and per-incident fees UPS, FedEx, and USPS add during the holiday season — for a shipper's weekly volume, ship-date range, service tier, and residential mix. It compares the three carriers per package per week and names the cheapest. It does not model base rates, fuel surcharges, DAS/EDAS, year-round residential or handling fees, DIM weight, or negotiated discounts: the output is the peak-surcharge delta only.
2 · Formulas
Dates are inclusive; rate resolution is per day; weeks are Sunday–Saturday.
rate(component, date) = rates[window containing date], else 0
daily_vol = weekly_volume / 7 (simple model; no ship-days-per-week input in v1)
perPkg(carrier, d) = demandRate(carrier, service_tier, d) × resMult(carrier, service_tier)
+ pct_addl_handling/100 × ahsRate(carrier, d)
+ pct_large_pkg/100 × largePackageRate(carrier, d)
+ pct_over_max/100 × overMaxRate(carrier, d)
resMult = pct_residential/100 if the component is residential-only, else 1 — UPS Ground and
FedEx Ground/Home Delivery demand surcharges are residential-only; UPS Ground Saver, FedEx Ground Economy,
and all USPS services are inherently residential-priced (multiplier 1); UPS Air and FedEx Express demand
applies regardless of residential per the embedded flag (see the UPS confidence note below).
USPS: perPkg(usps, d) = matrix[service|category|zone|weight] if d in window, else 0 — USPS
has no peak handling fees (year-round nonstandard fees are out of scope), so the handling terms are 0.
Over-maximum maps to FedEx's "Ground Unauthorized Package" charge.
weekPerPkg(c, w) = average of perPkg(c, d) over ship days d in week w — per-day averaging
handles weeks that straddle a window boundary automatically (e.g., the week of Oct 26, when UPS's demand
window has started but FedEx's hasn't).
weekTotal(c, w) = weekPerPkg × weekly_volume × (ship days in w) / 7
seasonTotal(c) = Σ over weeks of weekTotal(c, w)
Enterprise mode (optional, off by default, only for shippers billing >20,000 packages/week):
UPS: demandRate ← tierRate(peaking_factor, window kind) — the tier rate replaces the
base demand rate. FedEx: demandRate += residentialDeliveryTier(peaking_factor) for residential
packages, Oct 26 – Jan 17 — the tier charge is added on top of the published demand surcharge.
Enterprise outputs are labeled "estimate — UPS locks tiers season-long once qualified; FedEx re-rates
weekly."
3 · UPS 2026-27 confidence: cross-verified secondary + official-PDF corroboration
Confidence: SECONDARY (cross-verified, corroborated). Standard table: 2 independent secondaries agree cell-for-cell (refundretriever.com + reveelgroup.com, 21/21 cells, 2026-08-30; adversarially verified). High-volume matrix: 2 independent secondaries cell-for-cell (Intelligent Audit pub. 2026-08-28 + TransImpact PDF, 42/42 cells, 2026-08-31) plus Google-index snippet corroboration of the official UPS PDF ("August 26, 2026 Update") for ground-band values. Official UPS PDF at assets.ups.com still bot-blocked from atlas — cite for next-cycle verification.
| Window | Dates |
|---|---|
| W1 | Sep 27 – Oct 24, 2026 (handling-type fees only; demand = $0) |
| W2 | Oct 25 – Nov 21, 2026 (first demand shoulder) |
| W3 (peak) | Nov 22 – Dec 26, 2026 |
| W4 | Dec 27, 2026 – Jan 16, 2027 (post-peak shoulder) |
| Component | Applies to | Residential only | W1 | W2 | W3 | W4 |
|---|---|---|---|---|---|---|
| Demand — Ground Residential | ground | yes | $0 | $0.50 | $0.75 | $0.50 |
| Demand — Ground Saver (fka SurePost) | economy | no (inherently residential) | $0 | $0.50 | $0.75 | $0.50 |
| Demand — Air (NDA + 2DA/2DA AM/3DS)* | express | no* | $0 | $1.35 | $2.50 | $1.35 |
| Demand — Additional Handling | all | no | $8.75 | $8.75 | $11.90 | $8.75 |
| Demand — Large Package | all | no | $96.25 | $96.25 | $117.50 | $96.25 |
| Demand — Over Maximum Limits | all | no | $530 | $530 | $590 | $530 |
*UPS applies air demand surcharges to both residential and commercial air packages (Next Day Air + 2DA/2DA AM/3DS). Enterprise table confirms: Air Commercial stays at the flat window base at every band — it does not escalate. Source: Intelligent Audit + Reveel narrative, 2026-08-31.
UPS enterprise (high-volume) demand tiers
Applies only to customers billed >20,000 combined eligible packages in any week since Oct 2025; once qualified, applies all season (unlike FedEx). Peaking factor = current-week volume ÷ May 31 – Jun 27, 2026 average weekly baseline. Off-peak = W2 & W4; peak = W3. Only the 0–105% base row varies by window — the >105% tiers are constant across all windows (shoulder and peak identical); Air Commercial pays the flat window base at every band.
| Peaking factor | Grd Saver / Grd Res, off-peak | same, peak | Air Res, off-peak | Air Res, peak | Air Comm, off-peak | Air Comm, peak |
|---|---|---|---|---|---|---|
| 0–105% | $0.50 | $0.75 | $1.35 | $2.50 | $1.35 | $2.50 |
| >105–125% | $1.75 | $1.75 | $3.00 | $3.00 | $1.35 | $2.50 |
| >125–150% | $2.35 | $2.35 | $3.70 | $3.70 | $1.35 | $2.50 |
| >150–200% | $2.65 | $2.65 | $4.00 | $4.00 | $1.35 | $2.50 |
| >200–300% | $3.35 | $3.35 | $4.60 | $4.60 | $1.35 | $2.50 |
| >300–400% | $5.65 | $5.65 | $6.90 | $6.90 | $1.35 | $2.50 |
| >400% | $8.00 | $8.00 | $9.35 | $9.35 | $1.35 | $2.50 |
4 · FedEx 2026-27 confidence: primary source
Confidence: PRIMARY. Extracted verbatim from the fedex.com demand-surcharges HTML (July 22, 2026 update accordion), adversarially verified cell-for-cell by independent Python extraction — 21/21 rate cells and 48/48 calc/app schedule date values clean. See FEDEX_2026_EXTRACT.md (ops/research/peak-surcharge-2627/).
| Window | Dates |
|---|---|
| F1 | Sep 28 – Oct 25, 2026 (handling-type fees only) |
| F2 | Oct 26 – Nov 22, 2026 |
| F3 (peak) | Nov 23 – Dec 27, 2026 |
| F4 | Dec 28, 2026 – Jan 17, 2027 |
| Component | Applies to | Residential only | F1 | F2 | F3 | F4 |
|---|---|---|---|---|---|---|
| Demand — Express Overnight (FO/FPO/FSO)† | express | no | $0 | $1.30 | $2.55 | $1.30 |
| Demand — Ground Residential (Ground + Home Delivery) | ground | yes | $0 | $0.50 | $0.80 | $0.50 |
| Demand — Ground Economy (contract-only) | economy | no (inherently residential) | $0 | $2.55 | $4.05 | $2.55 |
| Demand — Additional Handling | all | no | $8.80 | $8.80 | $11.85 | $8.80 |
| Demand — Oversize | all | no | $95.75 | $95.75 | $117.25 | $95.75 |
| Demand — Ground Unauthorized Package | ground | no | $535 | $535 | $595 | $535 |
†FedEx splits express demand into two service groups: Overnight (FedEx First Overnight, Priority Overnight, Standard Overnight): $1.30/$2.55/$1.30; Day-Definite (2Day A.M., 2Day, Express Saver): $1.20/$2.35/$1.20. Engine uses the Overnight row. FedEx One Rate packages are excluded from all express demand surcharges.
FedEx enterprise — Demand — Residential Delivery Charge
Applies to shippers with >20,000 residential + Ground Economy packages/week; baseline = June 1-28, 2026; reassessed WEEKLY with a 2-week lag (the key difference vs UPS, whose qualification locks for the season). Charged per package on top of the published demand surcharges, Oct 26, 2026 – Jan 17, 2027. No charge at 0–105%.
| Peaking factor | Ground | Express |
|---|---|---|
| >105–125% | $1.70 | $3.05 |
| >125–150% | $2.40 | $3.75 |
| >150–200% | $2.70 | $4.05 |
| >200–300% | $3.35 | $4.70 |
| >300–400% | $5.60 | $6.95 |
| >400% | $8.00 | $9.35 |
5 · USPS 2026-27 confidence: PRIMARY
Confidence: PRIMARY. The full matrix below was extracted verbatim from the official USPS newsroom press release (about.usps.com, Aug 25, 2026) and confirmed cell-for-cell against PR Newswire (byte-identical). Docket CP2026-10; filed, pending favorable PRC review as of 2026-08-26. Effective midnight Central Oct 4, 2026 through midnight Central Jan 17, 2027 (modeled as inclusive ship dates Oct 4 – Jan 16, 2027). One flat window — USPS fees vary by service, zone, and weight, not by week. Gap: Parcel Select zone-neutrality stated implicitly ("all entries"); PRC filing may have zone detail. Anomaly: commercial GA Zones 5–9, 26–70 lb ($7.70) exceeds the retail value ($7.50) by $0.20 — both verbatim from the official press release; encoded independently.
Commercial rates (per package)
| Service / zones | 0–3 lb | 4–10 lb | 11–25 lb | 26–70 lb† |
|---|---|---|---|---|
| Priority Mail & Ground Advantage, Zones 1–4 | $0.40 | $0.65 | $1.05 | $3.15 |
| Parcel Select (all entries, no zone split in press release) | $0.40 | $0.50 | $0.80 | $2.35 |
| Priority Mail, Zones 5–9 | $0.85 | $1.75 | $3.85 | $9.10 |
| Ground Advantage, Zones 5–9‡ | $0.55 | $1.05 | $1.75 | $7.70 |
| Priority Mail Express, Zones 1–4 | $1.40 | $2.10 | $4.90 | $12.55 |
| Priority Mail Express, Zones 5–9 | $2.35 | $5.55 | $10.50 | $18.20 |
†26–70 lb cells include Oversized. Cubic mapping: cubic tiers 1–3 → 0–3 lb cell; PM cubic 4–5
and GA cubic 4–9 → 4–10 lb cell; GA cubic 10 → 11–25 lb cell.
‡Anomaly: commercial GA Zones 5–9, 26–70 lb ($7.70) is $0.20 higher than retail ($7.50) — verbatim from official press release; not a transcription error.
| Commercial flat rate | Surcharge |
|---|---|
| Priority Mail large flat-rate box | $1.75 |
| Priority Mail all other flat rate | $0.85 |
| Priority Mail Express flat-rate envelope | $2.35 |
Retail rates (per package)
| Service / zones | 0–3 lb | 4–10 lb | 11–25 lb | 26–70 lb† |
|---|---|---|---|---|
| Priority Mail & Ground Advantage, Zones 1–4 | $0.50 | $0.80 | $1.25 | $3.90 |
| Priority Mail, Zones 5–9 | $1.00 | $2.10 | $4.30 | $9.10 |
| Ground Advantage, Zones 5–9 | $0.75 | $1.40 | $2.75 | $7.50 |
| Priority Mail Express, Zones 1–4 | $1.40 | $2.45 | $5.05 | $12.70 |
| Priority Mail Express, Zones 5–9 | $2.35 | $6.30 | $11.70 | $20.80 |
| Retail flat rate | Surcharge |
|---|---|
| Priority Mail large flat-rate box | $2.10 |
| Priority Mail all other flat rate | $1.00 |
| Priority Mail Express flat-rate envelope | $2.35 |
USPS 2026-27 stacking caveat: USPS's separate 8% transportation-related time-limited increase (Apr 26, 2026 – Jan 17, 2027) lives in base rates — it is not a peak surcharge, it is excluded from this tool, and the 2026-27 peak surcharge stacks on top of it. USPS announcement.
6 · What the tool refuses to do
- Negotiated / contract rates. Many mid-size contracts waive or discount demand surcharges — the tool computes PUBLISHED list surcharges only.
- Invoice prediction. Excludes base rates, fuel surcharges, DAS/EDAS, year-round residential & handling fees, and DIM weight. The output is the peak-surcharge DELTA only.
- 2027-28 numbers before publication. This tool now shows the verified 2026-27 season for all three carriers. The tool never extrapolates next season's unpublished rates.
- Enterprise tiers without a user-entered peaking factor (we cannot know your baseline); enterprise outputs are labeled "estimate — UPS locks tiers season-long once qualified; FedEx re-rates weekly."
- USPS 2026-27 stacking caveat: the separate 8% transportation time-limited base-rate increase (Apr 26, 2026 – Jan 17, 2027) is excluded; the 2026-27 peak surcharge stacks on top of it.
7 · Refresh protocol (2027-28 season)
New schedules are expected mid-July to September 2027, based on recent timing: UPS published Aug 27, 2026; FedEx published Jul 22, 2026; USPS filed Aug 25, 2026 (effective early October). On refresh:
- UPS: retry the assets.ups.com PDF (still bot-blocked from atlas as of 2026-08-31); fall back to Supply Chain Dive + refundretriever.com + reveelgroup.com cross-check, requiring 2+ agreeing sources per cell. High-volume matrix: Intelligent Audit + TransImpact PDF were the 2026-27 sources; try those and Shipium + Pitney Bowes (slow to update — ~mid-Sept per 2026 cadence).
- FedEx: the HTML was accessible in 2026; retry fedex.com demand-surcharges page directly. Note the two-tier express split (Overnight vs Day-Definite) that first appeared in 2026-27.
- USPS: watch about.usps.com newsroom in early August; pull the press-release HTML for the matrix; check for post-filing revisions and the PRC docket (CP2026-10 was the 2026 docket); price tables at pe.usps.com. Note the GA Zones 5–9, 26–70 lb commercial > retail anomaly — verify whether it persists.
- Write the new season's data, bump last-verified date, and update header copy. If Sept 15 passes without all three carriers published, show per-carrier "pending" states rather than stale-as-current.
Sources
- USPS 2026-27 (PRIMARY — official newsroom press release, docket CP2026-10): about.usps.com 2026 holiday price-change release · PR Newswire mirror (byte-identical, confirmed cross-check)
- USPS 2026-27 8% base-rate caveat: about.usps.com transportation-related time-limited price change (Apr 2026)
- UPS 2026-27 standard table (cross-verified secondaries, 21/21 cells): RefundRetriever: UPS peak surcharges 2026 · Reveel: UPS 2026 peak demand surcharges
- UPS 2026-27 high-volume matrix (cross-verified, 42/42 cells): Intelligent Audit: UPS 2026 holiday surcharges · TransImpact PDF (2026-27 UPS Demand Surcharges — Final; read via pdftoppm on atlas)
- UPS 2026-27 official (bot-blocked from atlas — for refresh verification): assets.ups.com demand surcharges PDF ("August 26, 2026 Update") · ups.com peak-surcharges page
- UPS 2026-27 announcement context: Supply Chain Dive: UPS 2026 peak surcharges (Aug 27, 2026)
- FedEx 2026-27 (PRIMARY — fedex.com HTML, adversarially verified): fedex.com demand surcharges (Updated July 22, 2026) · fedex.com U.S. Export Demand Surcharges PDF (May 7, 2026)
Disclaimer: planning estimates from published list schedules only — not your negotiated rates, and not pricing, accounting, or business advice. Carrier schedules can be revised mid-season; verify against your carrier agreement before budgeting.