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GDS and TDS are the two ratios a Canadian lender checks first: how much of your gross income goes to housing, and how much goes to housing plus every other debt. Enter your numbers below.
Published: 2026-08-08 · Verified: 2026-08-08 · Author: usecos.app Research & Engineering
Direct answer
Direct answer: GDS is housing costs (mortgage payment, property tax, heating, 50% of condo fees) divided by gross income; TDS adds every other debt payment on top. CMHC's published maximum for insured mortgages is 39% GDS and 44% TDS. A household earning $120,000 with a $2,200 mortgage payment, $400/mo property tax and $150/mo heating sits at 27.5% GDS — well within guideline.
Jump to the calculator ↓Select a Canadian homebuyer scenario or customize your exact numbers.
All applicants combined, before tax.
Principal and interest only.
Car loans, credit cards, student loans, support payments.
50% counts in GDS/TDS.
GDS Ratio
0.0%
Within guideline
CMHC Max Benchmark: 39%
TDS Ratio
0.0%
Within guideline
CMHC Max Benchmark: 44%
Eligible for CMHC / OSFI Insured Mortgage Qualification
Both your housing costs (27.5% GDS) and total debt obligations (31.5% TDS) satisfy federal guideline B-20 limits (39% / 44%).
Gross Monthly
$10,000/mo
Income ÷ 12
Housing (GDS)
$2,750/mo
Mortgage + tax + heat
Total (TDS)
$3,150/mo
Housing + debts
Follow OSFI B-20 approval guidelines and simulate debt payoff strategies to expand your mortgage borrowing power.
Essential debt-service verification steps for prime Canadian lenders.
Federally regulated lenders qualify your GDS/TDS at the higher of your contract rate + 2.00% or 5.25% floor. Ensure your budget accounts for stress-test headroom.
Every $300/month in revolving minimum debt payments reduces your maximum mortgage borrowing capacity by ~$55,000. Pay down revolving debt before pre-approval.
A $650/month car payment counts directly against your 44% TDS limit, reducing mortgage approval by up to $115,000. Delay financing a vehicle until after mortgage closing.
Under CMHC and OSFI rules, exactly 50% of monthly condo maintenance fees are added directly to your housing costs when calculating GDS and TDS.
If your TDS exceeds 44%, adding an immediate family co-signer pools gross verifiable household income to satisfy standard tier-1 bank debt-servicing limits.
Under OSFI rules, every $100/month of non-mortgage debt (auto loans, lines of credit, student loans) shrinks your mortgage pre-approval by approximately $17,500.
Current TDS Ratio
31.5%
Max limit: 44.0%
New TDS After Paydown
27.5%
Reduced by -4.0%
Purchasing Power Expansion
+$70,000.00
Extra qualified home price
Move from monthly payment estimate to real qualification and cost breakdown.
Test your income against OSFI GDS (39%) & TDS (44%) stress-test benchmark.
See the 5-year and 10-year net-worth breakeven for this property value.
Calculate provincial Land Transfer Tax, legal fees, and CMHC insurance premium.
| Scenario | Inputs | Result | Interpretation |
|---|---|---|---|
| $120,000 income, $2,200 payment | $400/mo tax, $150 heat, no condo, $400 other debt | 27.5% GDS / 31.5% TDS | Well within guideline on both ratios. |
| $96,000 income, $1,800 payment, condo | $0 tax, $0 heat, $600 condo fees, $0 other debt | 26.25% GDS / 26.25% TDS | Only 50% of condo fees ($300) count toward the ratio. |
| $85,000 income, $2,300 payment | $350/mo tax, $175 heat, no condo, $650 other debt | 38.7% GDS / 47.7% TDS | GDS is at the limit; TDS is over the 44% guideline — other debt is the problem, not the mortgage. |
GDS = (payment + property tax + heating + 50% condo fees) ÷ gross income
TDS = (GDS costs + other debt payments) ÷ gross income
Both ratios use the same monthly gross income denominator — all applicants' income, combined, before tax. TDS is never lower than GDS, because it includes everything GDS includes plus more.
Methodology: the calculator converts your annual income and property tax to monthly figures, adds heating and 50% of condo fees to the mortgage payment for the GDS numerator, adds other monthly debt for the TDS numerator, then divides each by monthly gross income. It follows CMHC's published GDS/TDS formula.
| Ratio | CMHC maximum | Covers |
|---|---|---|
| GDS | 39% | Mortgage payment, property tax, heating, 50% of condo fees |
| TDS | 44% | Everything in GDS, plus car loans, credit cards, student loans and other debt |
39%/44% is CMHC's published maximum for insured mortgages. Individual lenders can apply stricter internal limits — confirm the number that applies to your file with your lender or broker before relying on this result.
If your ratios exceed OSFI B-20 (39% GDS / 44% TDS) limits, here is how Canadian mortgage brokers legally restructure deals for approval:
| Stumbling Block | Underwriting Impact | Approval Rescue Strategy | Borrowing Capacity Restored |
|---|---|---|---|
| High Car Loan / Lease ($650/mo) | Pushes TDS over 44% while GDS passes cleanly | Pay off balance with non-registered savings or re-amortize vehicle over longer term prior to application. | Restores ~$115,000 in mortgage pre-approval |
| High Condominium Fees ($500/mo) | 50% ($250/mo) added directly to both GDS and TDS numerators | Shift search to freehold townhouses or properties with modest reserve fund contributions. | Restores ~$45,000 in purchasing power |
| Self-Employed / Declining Net Income | Big 5 banks require 2-year average T4/NOA Line 15000 | Utilize Alternative / Credit Union B-Lender BFS (Business-for-Self) programs permitting higher 42% GDS / 47% TDS ratios. | Enables approval with 10%–15% gross add-backs |
| Sole Applicant Income Gap | Single income ($85k) cannot qualify at stress rate (contract + 2%) | Add immediate parent or partner as non-occupant guarantor / co-signer on title. | Combines household income, dropping TDS below 36% |
Lenders generally want GDS at or below 39% and TDS at or below 44% — the maximum ratios CMHC publishes for insured mortgages. Lower is safer: a ratio close to the maximum leaves little room for a rate increase, an income drop or an unexpected expense.
GDS (Gross Debt Service) covers housing costs only: mortgage payment, property tax, heating, and 50% of condo fees. TDS (Total Debt Service) adds every other debt payment — car loans, credit cards, student loans, support payments — on top of those same housing costs. TDS is always equal to or higher than GDS.
CMHC's guidance treats half of monthly condominium fees as a housing cost for GDS/TDS purposes, on the basis that a portion typically covers reserve funds and building costs rather than day-to-day carrying cost. Non-condo properties skip this line entirely.
Enter your real monthly heating bill if you know it — from a past bill or the seller's disclosure. If you don't have a figure yet, CMHC directs lenders to use a reasonable estimate based on the property's size, location and heating type; this calculator does not generate that estimate for you.
39%/44% is CMHC's published maximum for insured mortgages. Individual lenders can apply stricter internal limits depending on credit score, mortgage type, and whether the mortgage is insured or conventional. Confirm the specific limit that applies to you with your lender or broker.
Interest rates shown on UseCOS tools come from Bank of Canada data and carry the date the Bank published them. Tax figures follow the Canada Revenue Agency's published rules for the tax year shown. Other benchmarks are drawn from OSFI and provincial regulators. Always confirm current figures at the official source.
UseCOS provides transparent educational estimates and math comparisons for personal planning. Tools do not guarantee lender approval, tax compliance, or specific mortgage terms.
For binding mortgage rate commitments, loan contracts, or official tax filings, please consult a licensed Canadian mortgage broker, CPA, or official lender representative.